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Unit- 1
1.1 Public-switched telephone network (PSTN)
Public Switched Telephone Network (PSTN) is a domestic telecommunications network usually accessed by
telephones, key telephone systems, private branch exchange trunks, and data arrangements. The Public Switched
Telephone Network (PSTN), also known as Plain Old Telephone Service (POTS), is the wired phone system over
which landline telephone calls are made. The PSTN relies on circuit switching. To connect one phone to another,
the phone call is routed through numerous switches operating on a local, regional, national or international level.
The connection established between the two phones is called a circuit.
In the early days, phone calls traveled as analog signals across copper wire. Every phone call needed its own
dedicated copper wire connecting the two phones. That's why you needed operators' assistance in making calls. The
operators sat at a switchboard, literally connecting one piece of copper wire to another so that the call could travel
across town or across the country. Long-distance calls were comparatively expensive, because you were renting the
use of a very long piece of copper wire every time you made a call.
Routing calls requires multiple switching offices. The phone number itself is a coded map for routing the call. For
example, we have 10-digit phone numbers.



The first three digits are the area code or national destination code (NDC), which helps route the call to
the right regional switching station.
The next three digits are the exchange, which represents the smallest amount of circuits that can be
bundled on the same switch. In other words, when you make a call to another user in your same exchange - maybe a neighbor around the corner -- the call doesn't have to be routed onto another switch.
The last four digits of the phone number represent the subscriber number, which is tied to your specific
address and phone lines.
Within a company or larger organization, each employee or department might have its own extension. Extensions
from the main phone number are routed through something called a private branch exchange (PBX) that operates
on the premises.
To make an international call requires further instructions. The call needs to be routed through your long-distance
phone carrier to another country's long-distance phone carrier. To signal such a switch, you have to dial two separate
numbers, your country's exit code (or international access code) and the corresponding country code of the place
you're calling.
The basic digital circuit in the PSTN is a 64-kilobit-per-second channel, known as "DS0" or Digital Signal 0. DS0's
are also known as timeslots because they are multiplexed together in a time-division fashion.To carry a typical
phone call from a calling party to a called party, the audio sound is digitized at an 8 kHz sample rate using 8-bit
pulse code modulation.
Multiple DS0's can be multiplexed together on higher capacity circuits, such that 24 DS0's make a DS1 signal or T1
(the European equivalent is an E1, containing 32 64 kbit/s channels).
For more than a hundred years, the PSTN was the only bearer network available for telephony. Today, the mobile
telephone over wireless access network, which is carried through the PSTN trunking network, is becoming
increasingly popular. Other bearer networks for voice transmission include integrated service digital network
(ISDN), Digital Subscriber Line (DSL), Asynchronous Transfer Mode (ATM), frame relay and the Internet VOIP.
Today typical PSTN: Public Switched Telephone Network for voice and data communications with both wireless
and wire line access
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PSTN: Public Switched Telephone Network
The history of the PSTN is mostly the history of American Bell and AT&T. Here is a very brief timeline:



1875
o
1876
o
1878
o
o
o
Alexander Bell forms American Bell
Patent #174,465 - "IMPROVEMENT IN TELEGRAPHY" - Alexander Graham Bell's Telephone
First telephone exchange is built in New Haven, Connecticut.
First switchboard (and switchboard operator) in New Haven, CT.
The first telephone in the White House is installed.
This chapter provides a fundamental view of how the PSTN works, particularly in the areas of signaling and digital
switching.



Network Topology
PSTN Hierarchy
Access and Transmission Facilities
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Network and Data Communication
Network Timing
The Central Office
Evolving the PSTN to the Next Generation
Network Topology
The topology of a network describes the various network nodes and how they interconnect. Regulatory policies play
a major role in exactly how voice network topologies are defined in each country, but general similarities exist.
While topologies in competitive markets represent an interconnection of networks owned by different service
providers, monopolistic markets are generally an interconnection of switches owned by the same operator.
Depending on geographical region, PSTN nodes are sometimes referred to by different names. The three node types
we discuss in this chapter include:



End Office (EO)— Also called a Local Exchange. The End Office provides network access for the
subscriber. It is located at the bottom of the network hierarchy.
Tandem— Connects EOs together, providing an aggregation point for traffic between them. In some cases,
the Tandem node provides the EO access to the next hierarchical level of the network.
Transit— Provides an interface to another hierarchical network level. Transit switches are generally used
to aggregate traffic that is carried across long geographical distances.
There are two primary methods of connecting switching nodes. The first approach is a mesh topology, in which all
nodes are interconnected. This approach does not scale well when you must connect a large number of nodes. You
must connect each new node to every existing node. This approach does have its merits, however; it simplifies
routing traffic between nodes and avoids bottlenecks by involving only those switches that are in direct
communication with each other. The second approach is a hierarchical tree in which nodes are aggregated as the
hierarchy traverses from the subscriber access points to the top of the tree. PSTN networks use a combination of
these two methods, which are largely driven by cost and the traffic patterns between exchanges.
Figure 5-1 shows a generic PSTN hierarchy, in which End Offices are connected locally and through tandem
switches. Transit switches provide further aggregation points for connecting multiple tandems between different
networks. While actual network topologies vary, most follow some variation of this basic pattern.
Unit XIII: Network Layer and Internet Layer
The network layer is concerned with getting packets from the source all the way to the
destination. To achieve its goals, the network layer must know about the topology of the
communication subnet and choose appropriate paths through it. It must also take care to choose
routes to avoid overloading some of the communication lines and routers while leaving others
idle.
13.1 Network Layer and Design Issues
There are some issues that the designers of the network layer must grapple with. These
issues include the service provided to the transport layer and the internal design of the
subnet.
• Store-and-Forward Packet Switching: Store and Forward Switching refers
to a switching technique in which frames are completely processed before
being forwarded out the appropriate port. This processing includes calculating
the Cyclic Redundancy Check (CRC) and checking the destination address. In
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addition, frames must be temporarily stored until network resources are
available to forward the message.
A host with a packet to send transmits it to the nearest router, either on its own
LAN or over a point-to-point link to the carrier. The packet is stored there
until it has fully arrived so the checksum can be verified. Then it is forwarded
to the next router along the path until it reaches the destination host, where it
is delivered.
•
Services Provided to the Transport Layer:
The network layer provides services to the transport layer at the network
layer/transport layer interface. The network layer services have been designed
with the following goals in mind.
a. The services should be independent of the router technology.
b. The transport layer should be shielded from the number, type, and
topology of the routers present.
c. The network addresses made available to the transport layer should
use a uniform numbering plan, even across LANs and WANs.
Given these goals, the designers of the network layer have a lot of
freedom in writing detailed specifications of the services to be
offered to the transport layer whether the network layer should
provide connection-oriented service or connectionless service.
Connectionless Network Service performs datagram transport and
does not require a circuit to be established before data is transmitted.
Connection-oriented Network Service
requires explicit
establishment of a path or circuit between communicating transport
layer entities before transmitting data. The Internet offers
connectionless network-layer service and ATM networks offer
connection-oriented network-layer service.
•
Implementation of Connectionless Service: Does not require a session
connection between sender and receiver. The sender simply starts sending
packets (called datagrams) to the destination. This service does not have the
reliability of the connection-oriented method, but it is useful for periodic burst
transfers. Neither system must maintain state information for the systems that
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they send transmission to or receive transmission from. A connectionless
network provides minimal services. If connectionless service is offered,
packets are injected into the subnet individually and routed independently of
each other. In this context, the packets are frequently called datagrams and the
subnet is called a datagram subnet.
Routing within a datagram subnet.
•
Implementation of Connection-Oriented Service: Requires a session
connection (analogous to a phone call) be established before any data can
be sent. This method is often called a "reliable" network service. It can
guarantee that data will arrive in the same order. Connection-oriented
services set up virtual links between end systems through a network, as
shown in Figure 1. Note that the packet on the left is assigned the virtual
circuit number 01. As it moves through the network, routers quickly send
it through virtual circuit 01.
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For connection-oriented service, we need a virtual-circuit subnet. The idea
behind virtual circuits is to avoid having to choose a new route for every
packet sent. Instead,when a connection is established, a route from the
source machine to the destination machine is chosen as part of the
connection setup and stored in tables inside the routers. That route is
used for all traffic flowing over the connection, exactly the same way that
the telephone system works. When the connection is released, the virtual
circuit is also terminated. With connection-oriented service, each packet
carries an identifier telling which virtual circuit it belongs to
Routing within a virtual-circuit subnet.
13.2 Virtual Circuit and Data grams Subject
Comparison of Virtual-Circuit and Datagram Subnets
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Issue
Circuit setup
Datagram subnet
Not needed
VC subnet
Addressing
Each packet contains the full source Each packet contains a short VC
and destination address
number
State information
Subnet does not hold state
information
Each VC requires subnet table space
Routing
Each packet is routed independently
Route chosen during setup; all packets
of a VC follow this route
Effect of router
failures
None except for packets lost during
the crash
All VC's that passed through the failed
router are terminated
Quality of
service
Difficult to guarantee
Easy if enough resources can be
allocated during the setup procedure
Congestion
control
Difficult
Easy if enough buffers can be allocated
in advance for each VC
Required
Tradeoffs:


router memory space versus bandwidth
setup time versus address parsing time
13.3 Introduction of Routing
The main function of the network layer is routing packets from the source machine to the
destination machine, often requiring multiple hops. For broadcast networks routing is an
issue if source and destination are not on the same network. The routing algorithm is that
part of the network layer software responsible for deciding which output line an incoming
packet should be transmitted on. With VC's networks one speaks of session routing,
because a route remains in force for an entire user session (e.g. a login session or a file
transfer).
The following properties are desirable in a routing algorithm:

correctness and simplicity.

robustness, against software and hardware failures, traffic changes and
topology changes for very long periods.

stability, some algorithms never converge to an equilibrium.

fairness and optimality, which are conflicting goals.
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If A-A', B-B' and C-C' have enough traffic to saturate
the horizontal links, the total flow is maximized if the
X-X' traffic is shut off completely.
Several measures can be optimized, like maximizing
total network throughput or minimizing mean packet
delay. Note that these goals are in conflict, operating
any queuing system near maximal capacity implies
long queuing delays. As a compromise, many
networks attempt to minimize the number of hops a
packet must make, this tends to improve the delay and
reduces the amount of bandwidth consumed, which
tends to improve the throughput as well.
Routing algorithms can be grouped into two major classes: nonadaptive and
adaptiveNonadaptive algorithms calculate the routes from any source to any destination in
advance, off-line, and download this information to all routers when the network is booted. This
is also called static routing.
Adaptive algorithms change their routing decisions to reflect changes in topology and usually
traffic as well. They differ in where they get their information from (e.g. locally, from adjacent
routers, from all routers), when they change the routes (e.g. every n seconds, when the load or
topology changes) and what metrics used for optimization (e.g. distance, number of hops,
estimated transit time, cost for carriers).
The optimality principle
One can make a statement about
optimal routes without regard to
network topology or traffic. The
optimality principle states that if
router J is on the optimal path
from router I to router K, then the
optimal path from J to K also falls
along the same route.
As a consequence, the set of
optimal routes from all sources to
a given destination form a tree
routed at the destination. This is
shown here using as distance
metric the number of hops. Note
that other trees with the same path
length exist.
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Such a tree is called a sink tree, as it does not contain loops, each packet will be delivered in a
bounded number of hops.
13.4 Shortest path Routing Algorithm
A form of Routing which attempts to send Packets of data over a network in such a way
that the path taken from the sending computer to the recipient computer is minimized. The
path can be measured in either physical distance or in the number of HOPS. This form of
routing uses a NON-ADAPTIVE ROUTING ALGORITHM. Here the subnet is described
as an undirected graph, with each node representing a router and each arc representing a
communication link. Each arc is labeled with a length and Dijkstra's (or another) algorithm
is used to compute the path with the shortest length between any two nodes.
Several metrics of length are possible. When using the number of hops as a measure, each
arc as a length of 1, as was used in the figure above. If physical distance was taken as a
measure, M would go over L. In general the labels on the arcs can be computed as a
function of distance, bandwidth, average traffic, communication costs, mean queue length,
measured delay, etc.
Dijktstra's Algorithm:
At the end each node will be labeled (see Figure.1) with its distance from source node along the
best known path. Initially, no paths are known, so all nodes are labeled with infinity. As the
algorithm proceeds and paths are found, the labels may change reflecting better paths. Initially,
all labels are tentative. When it is discovered that a label represents the shortest possible path
from the source to that node, it is made permanent and never changed thereafter.
Look at the weighted undirected graph of Figure.1(a), where the weights represent, for example,
distance. We want to find shortest path from A to D. We start by making node A as permanent,
indicated by a filled in circle. Then we examine each of the nodes adjacent to A (the working
node), relabeling each one with the distance to A. Whenever a node is relabeled, we also label it
with the node from which the probe was made so that we can construct the final path later.
Having examined each of the nodes adjacent to A, we examine all the tentatively labeled nodes
in the whole graph and make the one with the smallest label permanent, as shown in Figure.1(b).
This one becomes new working node.
We now start at B, and examine all nodes adjacent to it. If the sum of the label on B and the
distance from B to the node being considered is less than the label on the node, we have a shorter
path, so the node is relabeled. After all the nodes adjacent to the working node have been
inspected and the tentative labels changed if possible, the entire graph is searched for the
tentatively labeled node with the smallest value. This node is made permanent and becomes the
working node for the next round. The Figure. 1 shows the first five steps of the algorithm.
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Note: Dijkstra's Algorithm is applicable only when cost of all the nodes is non-negative.
13.5 Flow Based Routing Algorithm
Flow based routing considers the flow in the network; mean consider the amount of traffic
in the network before deciding on which outgoing line to place the packet. The key here is
to be able to characterize the nature of the traffic flows over time. The basic idea behind
the algorithm, is that any given line, if the capacity and average flow are known, it is
possible to compute the mean packet delay on that line from queuing theory. The routing
problem thus reduces to finding the routing algorithm that produces the minimum average
delay for the subnet.
In flow-based routing, an initial packet or group of packets is identified to determine if they are
flowing to a common destination and if the packet is part of a larger sequence of packets, with
the latter occurring by examining packet sequence numbers and the window size negotiated
during a TCP/IP session. During this initial flow learning process, the first or first few packets
are routed. Once a flow is identified, a mechanism is used to inform all intermediate devices
between flow points of the flow so they can use switching instead of routing.
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One of the most popular methods used to identify a flow is to prefix a tag to the packet. This
technique, which is referred to as tag switching, was initially used by Cisco Systems prior to the
standardization of MPLS.
Figure 11.29 illustrates an example of the partial construction of router flow tables assuming the
use of packet tagging. In this example, assume a flow from station 1 on LAN A to station 5 on
LAN 3 was identified and assigned a tag value of 6. Router 1 would prefix each packet inbound
from port 2 that meets the flow criteria with tag number 6 and by examining its flow table switch
packets with tag 6 out port 3. At router 2, packets inbound with a tag value of 6 would be
switched out of port 3. In tag switching, each router between flow points only has to examine the
tag to determine how to switch the incoming packet, significantly enhancing the packet per
second processing rate of the switch/router. However, each router between flow points must be
capable of supporting tag switching or another type of layer 3 forwarding based upon the type of
forwarding used by the network.
Figure 11.29: Flow-Based Routing Using Packet Tagging Assuming Flow from Station 1 on
LAN A to Station 5 on LAN 3 Is Identified by Tag Number 6
Although flow-based routing can considerably enhance the packet processing rate of
switch/routers, this method of routing originally represented proprietary solutions that did not
provide interoperability between different vendor products. This situation changed with the
standardization of MPLS.
A current limitation of flow-based routing is the fact that you cannot use such network
applications as traceroute to determine the route to a destination because the use of tags or labels
results in a proprietary route development mechanism through the network. However, if you
need an extremely high packet processing capability, a flow-based layer 3 switching technique
may provide the solution to your organization's processing requirements.
13.6 Distance Vector Routing Algorithm
This algorithm, also called Bellman-Ford or Ford-Fulkerson, is a dynamic routing algorithm.
Each router maintains a table (a vector) giving the best known distance to each destination and
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which line to use to get there. These tables are updated by exchanging information with the
neighbors. It was the original ARPANET routing algorithm, also used in Internet under the name
RIP and in early versions of DECnet and Novell's IPX. Appletalk and Cisco routers use
improved versions.
A routing table in each router contains
for each router in the subnet the preferred
outgoing line for that router and an
estimate for the time or distance to that
destination. The metric might be number
of hops, queue length, time delay, etc.
Time delay can be measured by
periodically sending special ECHO
packets.
Once every T msec each router sends to
its neighbors a list of estimated time
delays to each destination. Router J then
calculates that it can go to e.g. G via A in
(8+18)=26, via I in 41, via H in 18 and
via K in 37 msec. The lowest (via H in 18
msec) is then chosen and put in the table.
In practice it has a serious drawback, it react slowly to bad news, know as the count-to-infinity
problem. Many ad-hoc solutions to this problem have been proposed. The widely used splithorizon hack (which reports the time to X on the line that packets for X are sent on as infinity)
has geometries in which it offers no improvement.
The core of the problem is that when X tells Y that it has a path somewhere, Y has no way of
knowing whether it itself is on the path.
13.7 Spanning Tree Routing
In some applications, hosts needs to send messages to many or all other hosts, like a host sending
a live radio or tv program. Sending a packet to all destinations simultaneously is called
broadcasting.
One possibility is to send a distinct packet to each destination. This wastes bandwidth and
requires that all destinations are known, but often it is the only possibility. Also flooding is a
possibility.
In multi-destination routing each packet contains a list of destinations, or a bit map indicating
the desired locations. A router receiving such a packet, checks all the destinations to determine
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the output lines that will be needed. For each of them a copy of the packet is generated with the
destinations reduced to the destinations reachable.
If the sink tree of the router originating the broadcast is known and other routers know which of
their lines belong to it, then a router receiving a packet over a sink tree line, sends it out over its
other sink tree lines. In stead of the sink tree, any other spanning tree can be used. This is a
subset of the subnet that contains all the routers but contains no loops. This method makes
excellent use of the bandwidth, generating the absolute minimum number of packets needed for
the job. A problem is that each router must have local knowledge of a global spanning tree.
With the reverse path forwarding
algorithm when a router receives a
broadcast packet, it checks whether
it arrives on the line the router uses
for sending packets to the source of
the broadcast. If so, it is likely that
the broadcast also followed that
route, and the packet is send out over all other lines of the router. Otherwise the packet is
discarded. The images show from left to right a subnet, a sink tree starting at I and the tree build
by reverse path forwarding. There after 5 hops and 24 packets the broadcast terminates,
compared to 4 hops and 14 packets had the sink tree be followed exactly. The reverse path
forwarding is both reasonable efficient and easy to implement
13.8 Congestion Control
When too many packets are present in
a subnet, performance degrades, a
situation called congestion. Buffers get
full, so packets are discarded leading to
more retransmissions and less packets
delivered to their destinations. Adding
memory might help, but then the
queues get longer leading to more
time-outs and retransmissions.
Congestion thus tends to feed upon
itself and become worse, leading to
collapse of the system.
Congestion control has to make sure that the subnet is able to carry the offered load. It is a global
issue, involving the behavior of all hosts and routers.
In contrast, flow control relates to the point-to-point traffic between a sender and a receiver,
making sure that the sender is not overloading the receiver.
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The reason congestion and flow control are often confused is that some congestion control
algorithm operate by sending messages back to various sources, telling them to "slow down".
Thus a host can get a "slow down" message either because the receiver cannot handle the load or
because the network cannot handle it.
General principles of congestion control
Two solutions to the presence of
congestion: increase the
destination
resources or decrease the load.
monitor system
explicit feedback The subnet might start using
Closed loop congestion info to action points
dial-up telephone lines to
implicit feedback
adjust system operation
temporarily increase the
bandwidth between points. Spare
routers, reserved for backups to make the system fault tolerant, could be put on-line. Decreasing
the load might include denying service to some users or degrading service to all or some users.
Open loop
prevention by good design
source
Congestion prevention policies
There are many policies on
different layers that affect
congestion
An important issue here is the
setting for timers, if they are set
too low extra retransmissions
occurs. Adaptive setting of timers
is needed.
Sliding window protocols using
selective repeat give less
retransmissions than using "go
back n". Using piggybacking for
acks reduces the number of
packets, but adds an extra timer
involving a chance of extra retransmissions. Using a smaller window size reduces the data rate
and thus help fight congestion.
When virtual circuits are used it is easy to deny new connections in case a congestion is near.
A routing algorithm can help avoid congestion by spreading traffic over all possible routes, in
stead of the best one.
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Congestion control for datagram subnets
Each router can easily monitor the utilization of its
output lines and other resources. In the old DECNET
a warning bit was set in the header of a packet send
out over a too busy line or when the router is low on
buffer space. At the destination, the transport entity
copied this bit into the next acknowledgment sent to
the source, which reacts by reducing the transmission
rate. This continues when more warning bits come in.
When no more warning bits arrive, the transmission
rate is increased slowly.
A router can also directly send a choke packet back
to the source host of a packet send out over a too
busy line. That packet is tagged so that it will not
generate more choke packets on its way. When the
source host receives the choke packet, it reduces its
rate to the specified destination by a certain fraction.
If it receives a choke packet in reaction to its new
rate, it reduces again by that fraction.
For high speeds or long distances, the reaction is too
slow. With hop-by-hop choke packets each
intermediate router also reacts on a choke packet by
reducing its sending rate. For that it needs sufficient buffers to store the packets which still come
in at a too high rate.
13.9 Traffic Shaping and Leaky Bucket Algorithm
Quality of Service
Requirements
QoS is determined by four primary parameters:
reliability, delay, jitter and bandwidth. The table
shows how stringent these requirements are for
various applications.
ATM networks classify flows into 4 broad
categories with respect to their QoS demands, a
division which is also useful for other networks:
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1. Constant bit rate (e.g. telephony), attempts to simulate a wire, providing uniform
bandwidth and delay.
2. Variable bit rate (e.g. compressed videoconferencing),images must arrive in time
independent on how much they could be compressed.
3. Non-real-time variable bit rate (e.g. watching a movie over internet), a lot of buffering at
the receiver is allowed.
4. Available bit rate (e.g. file transfer), applications that are not sensitive to jitter or delay.
Techniques for achieving good QoS
Overprovisioning means to provide so much router capacity, buffer space and bandwidth that
all the packets just fly through easily. The problem with this is that it is expensive. But as time
goes on and design and technology improves, it sometimes even becomes practical. The
telephone system is an example, it is
rare to pick up a telephone and not
get a dial tone instantly.
Buffering. Flows can be buffered on
the receiving size before being
delivered to a monitor or speaker. It
does not affect the reliability or
bandwidth, it increases the delay, but
it smoothes out the jitter. For audio
and video on demand, jitter is a main
problem, so it helps here. Commercial web sites that contain streaming audio or video all use
players that buffer for about 10 seconds before starting to play. If the bandwidth is low, much
more must be buffered, or the whole play must be first stored on a local disk.
One of the main causes of congestion is that traffic is often bursty. If hosts could be made to
transmit in a more uniform rate, congestion would be less common. Traffic shaping is about
regulating the average rate and burstiness of data transmission, it is widely used in ATM.
The leaky bucket algorithm
to regulate the maximum
number of packets (or bytes)
per time unit. When the
bucket is full, packets are
discarded.
When the packets are all the
same size (as in ATM), the
algorithm can be used as
described. When variablesized packets are used it is
often better to allow for a
fixed number of bytes per tick.
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The token bucket algorithm
allows the output rate to speed
up to a certain maximum
when a large burst arrives
from the host computer.
Tokens are used to accumulate
rights to send packets or bytes.
Packets are less likely to be
discarded.
Sometimes a token bucket is
followed by a leaky bucket.
Unit XIII: Network Layer and Internet Layer
The network layer is concerned with getting packets from the source all the way to the
destination. To achieve its goals, the network layer must know about the topology of the
communication subnet and choose appropriate paths through it. It must also take care to choose
routes to avoid overloading some of thecommunication lines and routers while leaving others
idle.
13.10 Network Layer and Design Issues
There are some issues that the designers of the network layer must grapple with. These
issues include the service provided to the transport layer and the internal design of the
subnet.
• Store-and-Forward Packet Switching :Store and Forward Switching refers
to a switching technique in which frames are completely processed before
being forwarded out the appropriate port. This processing includes calculating
the Cyclic Redundancy Check (CRC) and checking the destination address. In
addition, frames must be temporarily stored until network resources are
available to forward the message.
A host with a packet to send transmits it to the nearest router, either on its own
LAN or over a point-to-point link to the carrier. The packet is stored there
until it has fully arrived so the checksum can be verified. Then it is forwarded
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to the next router along the path until it reaches the destination host, where it
is delivered.
•
Services Provided to the Transport Layer:
The network layer provides services to the transport layer at the network
layer/transport layer interface. The network layer services have been designed
with the following goals in mind.
d.The services should be independent of the router technology.
e. The transport layer should be shielded from the number, type, and
topology of the routers present.
f. The network addresses made available to the transport layer should
use a uniform numbering plan, even across LANs and WANs.
Given these goals, the designers of the network layer have a lot of
freedom in writing detailed specifications of the services to be
offered to the transport layer whether the network layer should
provide connection-oriented service or connectionless service.
Connectionless Network Service performs datagram transport and
does not require a circuit to be established before data is transmitted.
Connection-oriented Network Service
requires explicit
establishment of a path or circuit between communicating transport
layer entities before transmitting data. The Internet offers
connectionless network-layer service and ATM networks offer
connection-oriented network-layer service.
•
Implementation of Connectionless Service: Does not require a session
connection between sender and receiver. The sender simply starts sending
packets (called datagrams) to the destination. This service does not have the
reliability of the connection-oriented method, but it is useful for periodic burst
transfers. Neither system must maintain state information for the systems that
they send transmission to or receive transmission from. A connectionless
network provides minimal services.If connectionless service is offered,
packets are injected into the subnet individually and routed independently of
each other. In this context, the packets are frequently called datagrams and the
subnet is called a datagram subnet.
Routing within a datagram subnet.
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Implementation of Connection-Oriented Service:Requires a session
connection (analogous to a phone call) be established before any data can
be sent. This method is often called a "reliable" network service. It can
guarantee that data will arrive in the same order. Connection-oriented
services set up virtual links between end systems through a network, as
shown in Figure 1. Note that the packet on the left is assigned the virtual
circuit number 01. As it moves through the network, routers quickly send
it through virtual circuit 01.
For connection-oriented service, we need a virtual-circuit subnet. The idea
behind virtual circuits is to avoid having to choose a new route for every
packet sent. Instead,when a connection is established, a route from the
source machine to the destination machine is chosen as part of the
connection setup and stored in tables inside the routers. That route is
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used for all traffic flowing over the connection, exactly the same way that
the telephone system works. When the connection is released, the virtual
circuit is also terminated. With connection-oriented service, each packet
carries an identifier telling which virtual circuit it belongs to
Routing within a virtual-circuit subnet.
13.11 Virtual Circuit and Data grams Subject
Comparison of Virtual-Circuit and Datagram Subnets
Issue
Circuit setup
Datagram subnet
Not needed
Addressing
Each packet contains the full source Each packet contains a short VC
and destination address
number
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State information
Subnet does not hold state
information
Each VC requires subnet table space
Routing
Each packet is routed independently
Route chosen during setup; all packets
of a VC follow this route
Effect of router
failures
None except for packets lost during
the crash
All VC's that passed through the failed
router are terminated
Quality of
service
Difficult to guarantee
Easy if enough resources can be
allocated during the setup procedure
Congestion
control
Difficult
Easy if enough buffers can be allocated
in advance for each VC
Tradeoffs:


router memory space versus bandwidth
setup time versus address parsing time
13.12 Introduction of Routing
The main function of the network layer is routing packets from the source machine to the
destination machine, often requiring multiple hops. For broadcast networks routing is an
issue if source and destination are not on the same network. The routing algorithm is that
part of the network layer software responsible for deciding which output line an incoming
packet should be transmitted on. With VC's networks one speaks of session routing,
because a route remains in force for an entire user session (e.g. a login session or a file
transfer).
The following properties are desirable in a routing algorithm:

correctness and simplicity.

robustness, against software and hardware failures, traffic changes and
topology changes for very long periods.

stability, some algorithms never converge to an equilibrium.

fairness and optimality, which are conflicting goals.
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If A-A', B-B' and C-C' have enough traffic to saturate
the horizontal links, the total flow is maximized if the
X-X' traffic is shut off completely.
Several measures can be optimized, like maximizing
total network throughput or minimizing mean packet
delay. Note that these goals are in conflict, operating
any queuing system near maximal capacity implies
long queuing delays. As a compromise, many
networks attempt to minimize the number of hops a
packet must make, this tends to improve the delay and
reduces the amount of bandwidth consumed, which
tends to improve the throughput as well.
Routing algorithms can be grouped into two major classes: nonadaptive and
adaptiveNonadaptive algorithms calculate the routes from any source to any destination in
advance, off-line, and download this information to all routers when the network is booted. This
is also called static routing.
Adaptive algorithms change their routing decisions to reflect changes in topology and usually
traffic as well. They differ in where they get their information from (e.g. locally, from adjacent
routers, from all routers), when they change the routes (e.g. every n seconds, when the load or
topology changes) and what metrics used for optimization (e.g. distance, number of hops,
estimated transit time, cost for carriers).
The optimality principle
One can make a statement about
optimal routes without regard to
network topology or traffic. The
optimality principle states that if
router J is on the optimal path
from router I to router K, then the
optimal path from J to K also falls
along the same route.
As a consequence, the set of
optimal routes from all sources to
a given destination form a tree
routed at the destination. This is
shown here using as distance
metric the number of hops. Note
that other trees with the same path
length exist.
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Such a tree is called a sink tree, as it does not contain loops, each packet will be delivered in a
bounded number of hops.
13.13 Shortest path Routing Algorithm
A form of Routing which attempts to send Packets of data over a network in such a way
that the path taken from the sending computer to the recipient computer is minimized. The
path can be measured in either physical distance or in the number of HOPS. This form of
routing uses a NON-ADAPTIVE ROUTING ALGORITHM. Here the subnet is described
as an undirected graph, with each node representing a router and each arc representing a
communication link. Each arc is labeled with a length and Dijkstra's (or another) algorithm
is used to compute the path with the shortest length between any two nodes.
Several metrics of length are possible. When using the number of hops as a measure, each
arc as a length of 1, as was used in the figure above. If physical distance was taken as a
measure, M would go over L. In general the labels on the arcs can be computed as a
function of distance, bandwidth, average traffic, communication costs, mean queue length,
measured delay, etc.
Dijktstra's Algorithm:
At the end each node will be labeled (see Figure.1) with its distance from source node along the
best known path. Initially, no paths are known, so all nodes are labeled with infinity. As the
algorithm proceeds and paths are found, the labels may change reflecting better paths. Initially,
all labels are tentative. When it is discovered that a label represents the shortest possible path
from the source to that node, it is made permanent and never changed thereafter.
Look at the weighted undirected graph of Figure.1(a), where the weights represent, for example,
distance. We want to find shortest path from A to D. We start by making node A as permanent,
indicated by a filled in circle. Then we examine each of the nodes adjacent to A (the working
node), relabeling each one with the distance to A. Whenever a node is relabeled, we also label it
with the node from which the probe was made so that we can construct the final path later.
Having examined each of the nodes adjacent to A, we examine all the tentatively labeled nodes
in the whole graph and make the one with the smallest label permanent, as shown in Figure.1(b).
This one becomes new working node.
We now start at B, and examine all nodes adjacent to it. If the sum of the label on B and the
distance from B to the node being considered is less than the label on the node, we have a shorter
path, so the node is relabeled. After all the nodes adjacent to the working node have been
inspected and the tentative labels changed if possible, the entire graph is searched for the
tentatively labeled node with the smallest value. This node is made permanent and becomes the
working node for the next round. The Figure. 1 shows the first five steps of the algorithm.
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Note: Dijkstra's Algorithm is applicable only when cost of all the nodes is non-negative.
13.14 Flow Based Routing Algorithm
Flow based routing considers the flow in the network; mean consider the amount of traffic
in the network before deciding on which outgoing line to place the packet. The key here is
to be able to characterize the nature of the traffic flows over time. The basic idea behind
the algorithm, is that any given line, if the capacity and average flow are known, it is
possible to compute the mean packet delay on that line from queuing theory. The routing
problem thus reduces to finding the routing algorithm that produces the minimum average
delay for the subnet.
In flow-based routing, an initial packet or group of packets is identified to determine if they are
flowing to a common destination and if the packet is part of a larger sequence of packets, with
the latter occurring by examining packet sequence numbers and the window size negotiated
during a TCP/IP session. During this initial flow learning process, the first or first few packets
are routed. Once a flow is identified, a mechanism is used to inform all intermediate devices
between flow points of the flow so they can use switching instead of routing.
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One of the most popular methods used to identify a flow is to prefix a tag to the packet. This
technique, which is referred to as tag switching, was initially used by Cisco Systems prior to the
standardization of MPLS.
Figure 11.29 illustrates an example of the partial construction of router flow tables assuming the
use of packet tagging. In this example, assume a flow from station 1 on LAN A to station 5 on
LAN 3 was identified and assigned a tag value of 6. Router 1 would prefix each packet inbound
from port 2 that meets the flow criteria with tag number 6 and by examining its flow table switch
packets with tag 6 out port 3. At router 2, packets inbound with a tag value of 6 would be
switched out of port 3. In tag switching, each router between flow points only has to examine the
tag to determine how to switch the incoming packet, significantly enhancing the packet per
second processing rate of the switch/router. However, each router between flow points must be
capable of supporting tag switching or another type of layer 3 forwarding based upon the type of
forwarding used by the network.
Figure 11.29: Flow-Based Routing Using Packet Tagging Assuming Flow from Station 1 on
LAN A to Station 5 on LAN 3 Is Identified by Tag Number 6
Although flow-based routing can considerably enhance the packet processing rate of
switch/routers, this method of routing originally represented proprietary solutions that did not
provide interoperability between different vendor products. This situation changed with the
standardization of MPLS.
A current limitation of flow-based routing is the fact that you cannot use such network
applications as traceroute to determine the route to a destination because the use of tags or labels
results in a proprietary route development mechanism through the network. However, if you
need an extremely high packet processing capability, a flow-based layer 3 switching technique
may provide the solution to your organization's processing requirements.
13.15 Distance Vector Routing Algorithm
This algorithm, also called Bellman-Ford or Ford-Fulkerson, is a dynamic routing algorithm.
Each router maintains a table (a vector) giving the best known distance to each destination and
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which line to use to get there. These tables are updated by exchanging information with the
neighbors. It was the original ARPANET routing algorithm, also used in Internet under the name
RIP and in early versions of DECnet and Novell's IPX. Appletalk and Cisco routers use
improved versions.
A routing table in each router contains
for each router in the subnet the preferred
outgoing line for that router and an
estimate for the time or distance to that
destination. The metric might be number
of hops, queue length, time delay, etc.
Time delay can be measured by
periodically sending special ECHO
packets.
Once every T msec each router sends to
its neighbors a list of estimated time
delays to each destination. Router J then
calculates that it can go to e.g. G via A in
(8+18)=26, via I in 41, via H in 18 and
via K in 37 msec. The lowest (via H in 18
msec) is then chosen and put in the table.
In practice it has a serious drawback, it react slowly to bad news, know as the count-to-infinity
problem. Many ad-hoc solutions to this problem have been proposed. The widely used splithorizon hack (which reports the time to X on the line that packets for X are sent on as infinity)
has geometries in which it offers no improvement.
The core of the problem is that when X tells Y that it has a path somewhere, Y has no way of
knowing whether it itself is on the path.
13.16 Spanning Tree Routing
In some applications, hosts needs to send messages to many or all other hosts, like a host sending
a live radio or tv program. Sending a packet to all destinations simultaneously is called
broadcasting.
One possibility is to send a distinct packet to each destination. This wastes bandwidth and
requires that all destinations are known, but often it is the only possibility. Also flooding is a
possibility.
In multi-destination routing each packet contains a list of destinations, or a bit map indicating
the desired locations. A router receiving such a packet, checks all the destinations to determine
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the output lines that will be needed. For each of them a copy of the packet is generated with the
destinations reduced to the destinations reachable.
If the sink tree of the router originating the broadcast is known and other routers know which of
their lines belong to it, then a router receiving a packet over a sink tree line, sends it out over its
other sink tree lines. In stead of the sink tree, any other spanning tree can be used. This is a
subset of the subnet that contains all the routers but contains no loops. This method makes
excellent use of the bandwidth, generating the absolute minimum number of packets needed for
the job. A problem is that each router must have local knowledge of a global spanning tree.
With the reverse path forwarding
algorithm when a router receives a
broadcast packet, it checks whether
it arrives on the line the router uses
for sending packets to the source of
the broadcast. If so, it is likely that
the broadcast also followed that
route, and the packet is send out over all other lines of the router. Otherwise the packet is
discarded. The images show from left to right a subnet, a sink tree starting at I and the tree build
by reverse path forwarding. There after 5 hops and 24 packets the broadcast terminates,
compared to 4 hops and 14 packets had the sink tree be followed exactly. The reverse path
forwarding is both reasonable efficient and easy to implement
13.17 Congestion Control
When too many packets are present in
a subnet, performance degrades, a
situation called congestion. Buffers get
full, so packets are discarded leading to
more retransmissions and less packets
delivered to their destinations. Adding
memory might help, but then the
queues get longer leading to more
time-outs and retransmissions.
Congestion thus tends to feed upon
itself and become worse, leading to
collapse of the system.
Congestion control has to make sure that the subnet is able to carry the offered load. It is a global
issue, involving the behavior of all hosts and routers.
In contrast, flow control relates to the point-to-point traffic between a sender and a receiver,
making sure that the sender is not overloading the receiver.
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The reason congestion and flow control are often confused is that some congestion control
algorithm operate by sending messages back to various sources, telling them to "slow down".
Thus a host can get a "slow down" message either because the receiver cannot handle the load or
because the network cannot handle it.
General principles of congestion control
Two solutions to the presence of
congestion: increase the
destination
resources or decrease the load.
monitor system
explicit feedback The subnet might start using
Closed loop congestion info to action points
dial-up telephone lines to
implicit feedback
adjust system operation
temporarily increase the
bandwidth between points. Spare
routers, reserved for backups to make the system fault tolerant, could be put on-line. Decreasing
the load might include denying service to some users or degrading service to all or some users.
Open loop
prevention by good design
source
Congestion prevention policies
There are many policies on
different layers that affect
congestion
An important issue here is the
setting for timers, if they are set
too low extra retransmissions
occurs. Adaptive setting of timers
is needed.
Sliding window protocols using
selective repeat give less
retransmissions than using "go
back n". Using piggybacking for
acks reduces the number of
packets, but adds an extra timer
involving a chance of extra retransmissions. Using a smaller window size reduces the data rate
and thus help fight congestion.
When virtual circuits are used it is easy to deny new connections in case a congestion is near.
A routing algorithm can help avoid congestion by spreading traffic over all possible routes, in
stead of the best one.
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Congestion control for datagram subnets
Each router can easily monitor the utilization of its
output lines and other resources. In the old DECNET
a warning bit was set in the header of a packet send
out over a too busy line or when the router is low on
buffer space. At the destination, the transport entity
copied this bit into the next acknowledgment sent to
the source, which reacts by reducing the transmission
rate. This continues when more warning bits come in.
When no more warning bits arrive, the transmission
rate is increased slowly.
A router can also directly send a choke packet back
to the source host of a packet send out over a too
busy line. That packet is tagged so that it will not
generate more choke packets on its way. When the
source host receives the choke packet, it reduces its
rate to the specified destination by a certain fraction.
If it receives a choke packet in reaction to its new
rate, it reduces again by that fraction.
For high speeds or long distances, the reaction is too
slow. With hop-by-hop choke packets each
intermediate router also reacts on a choke packet by
reducing its sending rate. For that it needs sufficient buffers to store the packets which still come
in at a too high rate.
13.18 Traffic Shaping and Leaky Bucket Algorithm
Quality of Service
Requirements
QoS is determined by four primary parameters:
reliability, delay, jitter and bandwidth. The table
shows how stringent these requirements are for
various applications.
ATM networks classify flows into 4 broad
categories with respect to their QoS demands, a
division which is also useful for other networks:
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5. Constant bit rate (e.g. telephony), attempts to simulate a wire, providing uniform
bandwidth and delay.
6. Variable bit rate (e.g. compressed videoconferencing),images must arrive in time
independent on how much they could be compressed.
7. Non-real-time variable bit rate (e.g. watching a movie over internet), a lot of buffering at
the receiver is allowed.
8. Available bit rate (e.g. file transfer), applications that are not sensitive to jitter or delay.
Techniques for achieving good QoS
Overprovisioning means to provide so much router capacity, buffer space and bandwidth that
all the packets just fly through easily. The problem with this is that it is expensive. But as time
goes on and design and technology improves, it sometimes even becomes practical. The
telephone system is an example, it is
rare to pick up a telephone and not
get a dial tone instantly.
Buffering. Flows can be buffered on
the receiving size before being
delivered to a monitor or speaker. It
does not affect the reliability or
bandwidth, it increases the delay, but
it smoothes out the jitter. For audio
and video on demand, jitter is a main
problem, so it helps here. Commercial web sites that contain streaming audio or video all use
players that buffer for about 10 seconds before starting to play. If the bandwidth is low, much
more must be buffered, or the whole play must be first stored on a local disk.
One of the main causes of congestion is that traffic is often bursty. If hosts could be made to
transmit in a more uniform rate, congestion would be less common. Traffic shaping is about
regulating the average rate and burstiness of data transmission, it is widely used in ATM.
The leaky bucket algorithm
to regulate the maximum
number of packets (or bytes)
per time unit. When the
bucket is full, packets are
discarded.
When the packets are all the
same size (as in ATM), the
algorithm can be used as
described. When variablesized packets are used it is
often better to allow for a
fixed number of bytes per tick.
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The token bucket algorithm
allows the output rate to speed
up to a certain maximum
when a large burst arrives
from the host computer.
Tokens are used to accumulate
rights to send packets or bytes.
Packets are less likely to be
discarded.
Sometimes a token bucket is
followed by a leaky bucket.
Unit XV: Network Management and Security
15.1 Introduction to Network management:
Network Management in general is a set of activities where a variety of tools, applications,
and devices are utilized by IT personnel to monitor and maintain information technology
networks. Network management means different things to different people.
The majority of network management architectures have the same fundamental structure
and set of relationships. End-user devices or stations, such as desk-top computers and
other network devices, either run software that enables them to send alerts when problems
are recognized or are periodically polled/queried to determine their health
Network management tools provide a variety of information to network operators and
engineers through monitoring and measuring a variety of performance metrics. The most
common metrics in the networking arena are availability, throughput, bandwidth
utilization, and latency (or delay).
Types of Monitoring/Management Tools: Network management systems vary from
simple one device applications to complex hierarchical and distributed system. A variety
of monitoring techniques are utilized by these systems. The ISO network management
model consists of five conceptual areas. performance management , configuration ,
accounting ,fault management ,security management
15.2 Internet Network-Management framework (SMI & HIB) & SNMP protocol
Simple Network Management Protocol (SNMP) is an "Internet-standard protocol for
managing devices on IP networks. Devices that typically support SNMP include routers,
switches, servers, workstations, printers, modem racks, and more." It is used mostly in
network management systems to monitor network-attached devices for conditions that
warrant administrative attention.
SNMP uses, one or more administrative computers called managers have the task of
monitoring or managing a group of hosts or devices on a computer network. Each
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managed system executes, at all times, a software component called an agent which
reports information via SNMP to the manager.
SNMP agents expose management data on the managed systems as variables. The protocol
also permits active management tasks, such as modifying and applying a new
configuration through remote modification of these variables. An SNMP-managed
network consists of three key components:



Managed device
Agent — software which runs on managed devices
Network management system (NMS) — software which runs
on the manager
A managed device is a network node that implements an SNMP interface that allows
unidirectional (read-only) or bidirectional access to node-specific information. Managed devices
exchange node-specific information with the NMSs. Sometimes called network elements, the
managed devices can be any type of device, including, but not limited to, routers, access servers,
switches, bridges, hubs, IP telephones, IP video cameras, computer hosts, and printers.
An agent is a network-management software module that resides on a managed device. An agent
has local knowledge of management information and translates that information to or from an
SNMP specific form.
A network management system (NMS) executes applications that monitor and control managed
devices. NMSs provide the bulk of the processing and memory resources required for network
management. One or more NMSs may exist on any managed network.
15.3 Data encryption, Data Encryption Standard(DES)
Data encryption refers to mathematical calculations and algorithmic schemes that
transform plaintext into cyphertext, a form that is non-readable to unauthorized parties.
The recipient of an encrypted message uses a key which triggers the algorithm mechanism
to decrypt the data, transforming it to the original plaintext version.
Before the internet, data encryption was seldom used by the public as it was more of a
military security tool. With the prevalence of online shopping, banking and other services,
even basic home users are now aware of data encryption.
Today's web browsers automatically encrypt text when making a connection to a secure
server. This prevents intruders from listening in on private communications. Even if they
are able to capture the message, encryption allows them to only view scrambled text or
what many call unreadable gibberish. Upon arrival, the data is decrypted, allowing the
intended recipient to view the message in its original form.
The Data Encryption Standard (DES), is the name of the Federal Information Processing
Standard (FIPS) 46-3, which describes the data encryption algorithm (DEA). The DEA is
also defined in the ANSI standard X3.92. DEA is an improvement of the algorithm Lucifer
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developed by IBM in the early 1970s. IBM, the National Security Agency (NSA) and the
National Bureau of Standards (NBS now National Institute of Standards and Technology
NIST) developed the algorithm. The DES has been extensively studied since its
publication and is the most widely used symmetric algorithm in the world.
In the beginning, 64-bit encryption was thought to be strong, but was proven wrong with
the introduction of 128-bit solutions. AES (Advanced Encryption Standard) is the new
standard and permits a maximum of 256-bits. In general, the stronger the computer, the
better chance it has at breaking a data encryption scheme.
Data encryption schemes generally fall in two categories: symmetric and asymmetric.
AES, DES and Blowfish use symmetric key algorithms. Each system uses a key which is
shared among the sender and the recipient. This key has the ability to encrypt and decrypt
the data. With asymmetric encryption such as Diffie-Hellman and RSA, a pair of keys is
created and assigned: a private key and a public key. The public key can be known by
anyone and used to encrypt data that will be sent to the owner. Once the message is
encrypted, it can only be decrypted by the owner of the private key.
Strong encryption like SSL (Secure Sockets Layer) and TLS (Transport Layer Security)
will keep data private, but cannot always ensure security. Websites using this type of data
encryption can be verified by checking the digital signature on their certificate, which
should be validated by an approved CA (Certificate Authority).
15.4 Principles of Cryptography (Symmetric Key & public key Encryption)
Cryptographic means the message is called plaintext or cleartext. Encoding the contents of the
message in such a way that hides its contents from outsiders is called encryption. The encrypted
message is called the ciphertext. The process of retrieving the plaintext from the ciphertext is
called decryption. Encryption and decryption usually make use of a key, and the coding method
is such that decryption can be performed only by knowing the proper key.
Cryptography is the art or science of keeping messages secret. Cryptanalysis is the art of
breaking ciphers, i.e. retrieving the plaintext without knowing the proper key. People who do
cryptography are cryptographers, and practitioners of cryptanalysis are cryptanalysts.
Cryptography deals with all aspects of secure messaging, authentication, digital signatures,
electronic money, and other applications. Cryptology is the branch of mathematics that studies
the mathematical foundations of cryptographic methods.
A method of encryption and decryption is called a cipher. Some cryptographic methods rely on
the secrecy of the algorithms; such algorithms are only of historical interest and are not adequate
for real-world needs. All modern algorithms use a key to control encryption and decryption; a
message can be decrypted only if the key matches the encryption key.
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There are two classes of key-based encryption algorithms, symmetric (or secret-key) and
asymmetric (or public-key) algorithms. The difference is that symmetric algorithms use the
same key for encryption and decryption (or the decryption key is easily derived from the
encryption key), whereas asymmetric algorithms use a different key for encryption and
decryption, and the decryption key cannot be derived from the encryption key.
Symmetric algorithms can be divided into stream ciphers and block ciphers. Stream ciphers
can encrypt a single bit of plaintext at a time, whereas block ciphers take a number of bits
(typically 64 bits in modern ciphers), and encrypt them as a single unit.
Asymmetric ciphers (also called public-key algorithms or generally public-key cryptography)
permit the encryption key to be public (it can even be published in a newspaper), allowing
anyone to encrypt with the key, whereas only the proper recipient (who knows the decryption
key) can decrypt the message. The encryption key is also called the public key and the
decryption key the private key or secret key.
15.5 Integrity & firewalls
In the network system integrity provides the assurance that information can only be accessed or
modified by those authorized to do so. Measures taken to ensure integrity include controlling the
physical environment of networked terminals and servers, restricting access to data, and
maintaining rigorous authentication practices. Data integrity can also be threatened by
environmental hazards, such as heat, dust, and electrical surges.
Practices followed to protect data integrity in the physical environment include: making servers
accessible only to network administrators, keeping transmission media (such as cables and
connectors) covered and protected to ensure that they cannot be tapped, and protecting hardware
and storage media from power surges, electrostatic discharges, and magnetism.
Network administration measures to ensure data integrity include: maintaining current
authorization levels for all users, documenting system administration procedures, parameters,
and maintenance activities, and creating disaster recovery plans for occurrences such as power
outages, server failure, and virus attacks.
Fire wall :
The term "fire wall" mean fireproof wall intended to prevent the spread of fire from one room or
area of a building to another. The Internet is a volatile and unsafe environment when viewed
from a computer-security perspective, therefore "firewall" is an excellent metaphor for network
security.
The most important aspect of a firewall is that it is at the entry point of the networked system it
protects. The logic is simple: a firewall must be positioned to control all incoming and
outgoing traffic.
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All Internet traffic travels in the form of packets. A packet is a quantity of data of limited size,
kept small for easy handling. When larger amounts of continuous data must be sent, it is broken
up into numbered packets for transmission and reassembled at the receiving end. All your file
downloads, Web page retrievals, emails -- all these Internet communications always occur in
packets.
A packet is a series of digital numbers basically, which conveys these things:
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The data, acknowledgment, request or command from the originating system
The source IP address and port
The destination IP address and port
Information about the protocol (set of rules) by which the packet is to be handled
Error checking information
In packet filtering, only the protocol and the address information of each packet is examined.
Filtering consists of examining incoming or outgoing packets and allowing or disallowing their
transmission or acceptance on the basis of a set of configurable rules, called policies.
Packet filtering policies may be based upon any of the following:
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Allowing or disallowing packets on the basis of the source IP address
Allowing or disallowing packets on the basis of their destination port
Allowing or disallowing packets according to protocol.
Unit XVI: Information Communication Technology and Cyber
Law
16.1 Social Impact of the ICT
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Information technology is the technology used to store, manipulate, distribute or create
information. The type of information or data is not important to this definition. The
technology is any mechanism capable of processing this data. Society can be defined as “a
community, nation, or broad grouping of people having common traditions, institutions,
and collective activities and interests.
Development of ICT : The identification of significant developments begins
chronologically in 1969.
1969:The Arpanet is introduced, funded by the department of defense.)
1970:The first automatic teller machine is introduced.
1971:The first single chip central processing unit was introduced, the Intel 4004.
1978:Ron Rivest, Adi Shamir and Leonard Adelman introduce the RSA cipher as a public
key cryptosystem.
1981:IBM introduces its first personal computer with an operating system developed by
Microsoft.
1983:The switchover to the TCP\IP protocol marks the beginning of the global Internet.
1985: Microsoft releases the Windows operating system.
1989: developed www
Late 1990’s:The emergence of electronic commerce.
Impact of ICT:
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The Workplace : The patterns of activities which employees undertake are also being
affected, in such areas as: organisational processes; work-patterns and skills; and
organisational structures.
Community Impacts : Beyond the workplace, communities are functioning differently
because of I.T. Some of the more important impacts are in the following areas: changes
within existing communities; the emergence of electronic communities.
Social Impacts : Society as a whole, and individuals within society, are being
significantly affected by IT. Some of the more important impacts are in the following
areas: equity of access to information; pricing; regulation; consumer rights; privacy; and
electronic freedoms.
Economic Impact : At a more general level, IT is affecting aspects of the national
economy, in particular in the following areas: employment levels; the distribution of
income; and access to education and training.
Legal Considerations :The law establishes the framework within which people's rights
and responsibilities exist, and can be enforced. IT is having an impact on some aspects of
the law, including: evidentiary questions; intellectual property, especially copyright; and
unintended contingent liabilities.
Cultural and National Sovereignty Issues :At a more abstract level still, IT is having an
impact on the larger communities to which people belong. Relevant topics in this area
include: cultural integrity; national sovereignty; and integrity of the currency.
Information Technology has already been blamed, among other things for:
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creating unemployment
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deskilling jobs
reducing the ability of governments to control their economies
invading privacy
increasing delinquency in children
manipulation of the 'truth'
pornography
16.1.1 Digital Divide
The world has benefited and affected enormously from the developments in Information
and Communications Technology (ICT). Not only it has enhanced business productivity, it
also permeates the social and political field in ways that have never been possible in the
past. Development of the information society and the wide-spread diffusion of ICT
give rise to new digital skills and competences that are necessary for employment,
education and training, self-development and participation in society.
Digital divide refers to the gap between people with effective access to digital and
information technology and those with very limited or no access at all .
The term digital divide refers to the increasing access gap between those who have and
those who do not have:
 access to information and communication technologies;
 access to content that benefits them socially and economically;
 skills to take advantage of ICT services;
 the ability to afford to pay for digital services.
Digital divides exist on local, national, and global levels.
16.2 Computer Ethics
Ethics is a set of moral principles that govern the behavior of a group or individual. Therefore,
computer ethics is set of moral principles that regulate the use of computers. Some common
issues of computer ethics include intellectual property rights (such as copyrighted electronic
content), privacy concerns, and how computers affect society.
For example, while it is easy to duplicate copyrighted electronic content, computer ethics would
suggest that it is wrong to do so without the author's approval. And while it may be possible to
access someone's personal information on a computer system, computer ethics would advise that
such an action is unethical.
As technology advances, computers continue to have a greater impact on society. Therefore,
computer ethics promotes the discussion of how much influence computers should have in areas
such as artificial intelligence and human communication. As the world of computers evolves,
computer ethics continues to create ethical standards that address new issues raised by new
technologies.
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Computer Ethics is a branch of practical philosophy which deals with how computing
professionals should make decisions regarding professional and social conduct.
The Ten Commandments of Computer Ethics from The Computer Ethics Institute
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not use a computer to harm other people.
not interfere with other people's computer work.
not snoop around in other people's computer files.
not use a computer to steal.
use a computer to bear false witness.
not copy or use proprietary software for which you have not paid.
not use other people's computer resources without authorization or proper compensation.
not appropriate other people's intellectual output.
think about the social consequences of the program you are writing or the system you are
designing.
always use a computer in ways that insure consideration and respect for your fellow
humans.
16.3 Intellectual Properties Right
Intellectual property (IP) refers to creations of the mind: inventions, literary and artistic works,
and symbols, names, images, and designs used in commerce. IP is divided into two categories:
Industrial property, which includes inventions (patents), trademarks, industrial designs, and
geographic indications of source; and Copyright, which includes literary and artistic works such
as novels, poems and plays, films, musical works, artistic works such as drawings, paintings,
photographs and sculptures, and architectural designs. Rights related to copyright include those
of performing artists in their performances, producers of phonograms in their recordings, and
those of broadcasters in their radio and television programs.
A patent is an exclusive right granted for an invention, which is a product or a process that
provides, in general, a new way of doing something, or offers a new technical solution to a
problem. In order to be patentable, the invention must fulfill certain conditions. A patent
provides protection for the invention to the owner of the patent. The protection is granted for a
limited period, generally 20 years. Patent protection means that the invention cannot be
commercially made, used, distributed or sold without the patent owner's consent. These
patent rights are usually enforced in a court, which, in most systems, holds the authority to stop
patent infringement. Conversely, a court can also declare a patent invalid upon a successful
challenge by a third party.
A trademark is a distinctive sign which identifies certain goods or services as those produced or
provided by a specific person or enterprise. Its origin dates back to ancient times, when
craftsmen reproduced their signatures, or "marks" on their artistic or utilitarian products. Over
the years these marks evolved into today's system of trademark registration and protection. The
system helps consumers identify and purchase a product or service because its nature and
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quality, indicated by its unique trademark, meets their needs. A trademark provides protection
to the owner of the mark by ensuring the exclusive right to use it to identify goods or services,
or to authorize another to use it in return for payment. Trademarks may be one or a combination
of words, letters, and numerals. They may consist of drawings, symbols, three- dimensional signs
such as the shape and packaging of goods, audible signs such as music or vocal sounds,
fragrances, or colors used as distinguishing features.
Copyright is a legal term describing rights given to creators for their literary and artistic works.
The kinds of works covered by copyright include: literary works such as novels, poems, plays,
reference works, newspapers and computer programs; databases; films, musical compositions,
and choreography; artistic works such as paintings, drawings, photographs and sculpture;
architecture; and advertisements, maps and technical drawings.
16.4 Privacy, Anonymity
Anonymity is derived from the Greek word ἀνωνυμία, anonymia, meaning "without a
name" or "namelessness". In colloquial use, anonymity typically refers to the state of an
individual's personal identity, or personally identifiable information, being publicly
unknown.
The problem of determining whether or not the identity of a communication partner is the
same as one previously encountered is the problem of authentication.
There are many reasons to hide your real identity when you use the Internet. You might
want to protect yourself against an oppressive government, or post personal messages to a
Usenet newsgroup without identifying yourself to the whole world as the poster. The
anonymity covers instructions and explanations on how to be anonymous on the Net.
Although everyone takes privacy in normal life for granted, trying to get the same level of
privacy on the Internet (or even on your own computer) is a little less accepted, and
sometimes a bit more complicated. While the general attitude his hard to change, many
ways exist to enhance your privacy online. The Privacy index lists programs such as PGP
and Securedrive to keep the contents of files secure. It also discusses other aspects of
electronic privacy.
16.5 Computer Crime
Cybercrime is criminal activity done using computers and the Internet. This includes anything
from downloading illegal music files to stealing millions of dollars from online bank accounts.
Cybercrime also includes non-monetary offenses, such as creating and distributing viruses on
other computers or posting confidential business information on the Internet.
Cybercrime is defined as crimes committed on the internet using the computer as either a tool or
a targeted victim. For example, hacking involves attacking the computer’s information and other
resources. It is important to take note that overlapping occurs in many cases and it is impossible
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to have a perfect classification system.
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Computer as a tool: When the individual is the main target of Cybercrime, the computer
can be considered as the tool rather than the target. These crimes generally involve less
technical expertise as the damage done manifests itself in the real world. Human
weaknesses are generally exploited. The damage dealt is largely psychological and
intangible, making legal action against the variants more difficult. These are the crimes
which have existed for centuries in the offline. Scams, theft, and the likes have existed
even before the development in high-tech equipment. The same criminal has simply been
given a tool which increases his potential pool of victims and makes him all the harder to
trace and apprehend.
Computer as a target: These crimes are committed by a selected group of criminals.
Unlike crimes using he computer as a tool, these crimes requires the technical
knowledge of the perpetrators. These crimes are relatively new, having been in existence
for only as long as computers have - which explains how unprepared society and the
world in general is towards combating these crimes. There are numerous crimes of this
nature committed daily on the internet. But it is worth knowing that Africans and indeed
Nigerians are yet to develop their technical knowledge to accommodate and perpetrate
this kind of crime.
“Any criminal activity that uses a computer either as an instrumentality, target or a means for
perpetuating further crimes comes within the ambit of cyber crime”
The following are the category of cyber criminals
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Unauthorized access to computer systems or networks / Hacking- This kind of offence is
normally referred as hacking in the generic sense.
Theft of information contained in electronic form-This includes information stored in
computer hard disks, removable storage media etc. Theft may be either by appropriating
the data physically or by tampering them through the virtual medium.
Email bombing- This kind of activity refers to sending large numbers of mail to the
victim, which may be an individual or a company or even mail servers there by ultimately
resulting into crashing.
Data diddling- This kind of an attack involves altering raw data just before a computer
processes it and then changing it back after the processing is completed. The electricity
board faced similar problem of data diddling while the department was being
computerised.
Salami attacks- This kind of crime is normally prevalent in the financial institutions or
for the purpose of committing financial crimes. An important feature of this type of
offence is that the alteration is so small that it would normally go unnoticed.
Denial of Service attack- The computer of the victim is flooded with more requests than
it can handle which cause it to crash. Distributed Denial of Service (DDoS) attack is also
a type of denial of service attack, in which the offenders are wide in number and
widespread. E.g. Amazon, Yahoo.
Virus / worm attacks- Viruses are programs that attach themselves to a computer or a file
and then circulate themselves to other files and to other computers on a network. They
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usually affect the data on a computer, either by altering or deleting it. Worms, unlike
viruses do not need the host to attach themselves to.
Logic bombs- These are event dependent programs. This implies that these programs are
created to do something only when a certain event (known as a trigger event) occurs.
Trojan attacks- This term has its origin in the word ‘Trojan horse’. In software field this
means an unauthorized programme, which passively gains control over another’s system
by representing itself as an authorised programme.
Internet time thefts- Normally in these kinds of thefts the Internet surfing hours of the
victim are used up by another person. This is done by gaining access to the login ID and
the password.
Web jacking-This term is derived from the term hi jacking. In these kinds of offences the
hacker gains access and control over the web site of another. He may even mutilate or
change the information on the site. This may be done for fulfilling political objectives or
for money.
The following are the crimes, which can be committed against the followings group
Against Individuals: –
i. Harassment via e-mails.
ii. Cyber-stalking.
iii. Dissemination of obscene material.
iv. Defamation.
v. Unauthorized control/access over computer system.
vi. Indecent exposure
vii. Email spoofing
viii. Cheating & Fraud
Against Individual Property: i. Computer vandalism.
ii. Transmitting virus.
iii. Netrespass
iv. Unauthorized control/access over computer system.
v. Intellectual Property crimes
vi. Internet time thefts
Against Organization: i. Unauthorized control/access over computer system
ii. Possession of unauthorized information.
iii. Cyber terrorism against the government organization.
iv. Distribution of pirated software etc.
16.6 Concept of Cyber Law:
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Cyber Law is the law governing computers and the Internet.In today's highly digitalized world,
almost everyone is affected by cyber law. Let us take a few examples: Almost all transactions in
shares are in demat form. Almost all companies extensively depend upon their computer
networks and keep their valuable data in electronic form. Government forms including income
tax returns, company law forms etc are now filled in electronic form. Consumers are
increasingly using credit cards for shopping. Most people are using email, cell phones and
SMS messages for communication.
Cyber crime cases such as online banking frauds, online share trading fraud, source code theft,
credit card fraud, tax evasion, virus attacks, cyber sabotage, phishing attacks, email hijacking,
denial of service, hacking, pornography etc are becoming common. Digital signatures and econtracts are fast replacing conventional methods of transacting business.
The area of law dealing with the use of computers and the Internet and the exchange of
communications and information thereon, including related issues concerning such
communications and information as the protection of intellectual property rights, freedom of
speech, and public access to information.
16.7 Area of Cyber Law
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16.8 Cyber Law in Nepal
Cyber Ethics and Cyber Crime
Background
In today's highly digitalized world, almost everyone is affected by cyber activities. Let us take a
few examples: Almost all transactions in shares are in demat form. Almost all companies
extensively depend upon their computer networks and keep their valuable data in electronic
form. Government forms including income tax returns, company law forms etc are now filled in
electronic form. Consumers are increasingly using credit cards for shopping. Most people are
using E-mail, Cell phones and SMS messages for communication. Even in "non-cyber crime"
cases, important evidence is found in computers/cell phones e.g. in cases of divorce, murder,
kidnapping, tax evasion, organized crime, terrorist operations, counterfeit currency etc.
Cyber crime cases such as online banking frauds, online share trading fraud, source code theft,
credit card fraud, tax evasion, virus attacks, cyber sabotage, phishing attacks, E-mail hijacking,
denial of service, hacking, pornography etc are becoming common. Digital signatures and econtracts are fast replacing conventional methods of transacting business. Information
technology in business presents major security challenges, poses serious ethical questions, and
affects society in significant ways. Business professionals have a responsibility to promote
ethical uses of information technology in the workplace. So it would be better to follow the
ethical guidelines in an organization. Here are some points mentioned as guidelines.
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Ethical Guidelines
a. Acting with integrity.
b. Increasing professional competence.
c. Setting high standards of personal performance.
d. Accepting responsibility for one.s own work.
e. Advancing the health, privacy, and general welfare of the public.
Cyber Ethics
Ethics are the principles of right and wrong individuals, acting as free moral agents, use
to make choices to guide their behavior. Information systems raise new ethical questions
for both individuals and societies because they create opportunities for intense social
change.
Ethics in an Information Society
Ethical decisions draw on the concepts of:
Ì Responsibility: Accepting the potential costs, duties, and obligations of one's decisions.
Ì Accountability: A feature of systems and social institutions, accountability means that
mechanisms are in place to determine who took responsible action and who is responsible
for an action.
Ì Liability: Refers to the existence of laws that permit individuals to recover the damages
done to them by other actors, systems, or organizations.
Ì Due process: Requires that laws are known and understood by all, and that individuals
can appeal to higher authorities to ensure laws were properly applied.
Cyber/Computer Crime
Cyber/Computer crime (the commission of illegal acts through the use of a computer against a
computer system) and computer abuse (the commission of acts involving a computer that may
not be illegal but are considered unethical) primarily committed by people inside the
organization is known as computer crime or cyber crime. For example, spam is unrequested junk
E-mail sent to thousands of Internet users. There are other ways to define cyber crime which are
given in bulleted format here.
a) The unauthorized use, access, modification and destruction of hardware, software,
data or network resources is a cyber crime.
b) The unauthorized copying of software and release of information is cyber crime.
c) Denying an end user access to his or her own hardware, software, data or network
resources.
Spam for Everyone
Spam E-mail massages hawking many kinds of products and services, including scams,
clog inboxes of employees in many industries.
What is being offered..... .... and to whom
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Why are People Drawn To Cyber Crime
a. First motivation factor is money.
b. To challenge the resources which are responsible to protect and maintain the information
and system security.
c. To acquire social recognition anyhow.
Why Is Internet a Popular Means to Commit Crime?
Ì Time convenience
Ì Location convenientce
Ì Difficult to locate the offenders
Type of Computer Crimes and Criminals
Ì Hacker: An outsides who has penetrated a computer system, usually with no criminal
intent.
Ì Cracker: A malicious hacker.
Social engineering: Getting around security systems by tricking computer users into
revealing sensitive information or gaining unauthorized access privileges.
Ì Cybercrimes: Illegal activities executed on the Internet.
Ì Identify theft: A criminal (the identity thief) poses as someone else.
Ì Cyberwar: War in which a country.s information systems could be paralyzed from
a massive attack by destructive software.
Ì Virus: Software that can attach itself to (.infect..) other computer programs without
the owner of the program being aware of the infection.
Hacking
Definition
Ì The obsessive use of computers, or the unauthorized access and use of networked
computer systems
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Common Hacking Tactics
Ì Denial of Service (DOS ): hammering a Website.s equipment with too many requests
for information, effectively clogging the system, slowing performance or even crashing
the site
Ì Scans: widespread probes of the Internet to determine types of computers, services,
and connections
Ì Sniffer: programs that covertly search individual packets of data as they pass through
the Internet, capturing passwords or entire contents
Ì Spoofing: faking an E-mail address or Web page to trick users into passing along
critical information like passwords or credit card numbers
Ì Trojan horse: a program that, unknown to the user, contains instructions that exploit
a known vulnerability in some software
Ì War dialing: programs that automatically dial thousands of telephone numbers in
search of a way in through a modem connection
Ì Password crackers: software that can guess passwords
Cyber law
Cyber law is generally known as the law of Internet including computers, computer networks,
data and software. The cyber law governs the legal issue of cyber space. Cyber law is
necessary due to following reasons:
i. To take advantage of globalization due in context of IT development.
ii. To reduce cyber crime.
iii. To maintain a norm.
iv. To solve the problems related to e-business transactions.
Different countries have given different names to cyber laws. The government of Nepal
has brought out an Electronic Transaction Act in 2061 BS which is known as Cyber Law
of Nepal. The government of Nepal has formed a High Level Commission for Information
Technology (HLCIT) to plan and publish the policy related to cyber law which consists
of Electronic Transaction Act, digital signature acts and many more.
Cyber Space
The cyber space refers to the virtual environment created by the Internet, computers,
computer communication and network and data of any organization.
Safe Internet for Children
Guide for Parents and Teachers
Internet provides access to enormous amount of information and many new forms of
communication to a large audience instantly. It reflects our physical world, containing all
the best and worst of what exists on the planet, and therefore, is also a place where children can
be seriously harmed. As in physical life, children need to be protected from harm and guided to
use the Internet. Yet often children know much more about computers and Internet then their
parents or teachers. You must realize that you have to teach your children to be safe.
What are the Risks?
1. Exposure to Inappropriate Materials
As children explore the Internet, they can come across images and information not appropriate
for them, like (extreme) pornography, (extreme) violence, racism, etc. They find these materials
by accident or seek them out deliberately. These materials are easily available and just one
mouse click away from children surfing the net. Involuntary exposure to pornography also
occurs through spam, popup, deception and luring practices of porno
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sites, or typing of innocent keywords on search engines. Also, Nepali children who have
never been online are known to have been exposed to pornographic materials downloaded
on to memory sticks and distributed through mobile phones.
There are also cases reported when they are confronted with popup windows that come up
every now and then to show pornographic links.
2. Exposure to Inappropriate and Potentially Dangerous Contact
Adults, who want to engage children in sexual acts or talk to them for sexual gratification,
will try to befriend vulnerable children and teens by pretending to be children themselves
or posing as a trusted adult. They will use manipulation to build a trust relationship or play
on teen.s desire for romance and adventure, slowly getting more intimate, including
confronting a child with use of sexually explicit images and use of Webcams. They often
use blackmail and guilt as methods to meet with the child in person.
3. Cyber Bullying
New technologies like Internet and mobile phones are increasingly used by bullies (most
of them children and young people themselves) to torment their victims by harassing, and
intimidating them, ranging from name-calling and physical threats to spreading rumors or
sending out inappropriate images of their victims. The victims of cyber bullying can feel
embarrassed, upset, depressed, or afraid, and as a result, their psychological wellbeing and
self-esteem can be seriously damaged.
4. Invasion of Privacy and Online Fraud
Children may (innocently) share personal information (like phone number, address, etc.)
or photographs of themselves or their family on social networking sites, when chatting or
playing games or by filling registration forms. Giving out this information can put children
and their family members at risk from child predators or Internet thieves.
5. File Sharing Abuse
Downloading and sharing files (e.g. music or videos) online can be risky. Especially, the
use of file sharing networks (peer to peer) might expose children to pornography and other
inappropriate content or put your computer at risk of spy ware and viruses, because they
are the least regulated part of the Internet. Also, downloading and uploading of copyrighted
materials is illegal. There are also sites that permit downloading and sharing of files legally
and risks are significantly lower.
How to Protect and Support Children Online
1. Talk to your children about what they do online and teach them about the Internet
applications like E-mails, online games, chat, messenger and social networks (e.g. Hi5
or Facebook). Your children will trust you and come to you for help once they feel
that you have at least a basic knowledge of these tools. Spend more time with your
children; encourage them to use the Internet in a positive way and talk with them about
the online risks and how they can protect themselves. Above all, teach them to trust
their instincts and make sure they inform you if they feel disturbed or scared of
something they experience online.
2. Keep the computer in your living room or other open area where you can easily
supervise your children.s online activity, not in the child.s private bedroom. Limit the
time your child spends online, because it can lead to addiction.
3. Install filtering/monitoring software in your family computer to prevent your children
from being exposed to unwanted content. Parental control tools can help to block
access to known pornography sites, filter unsuitable content, limit the time your children
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can stay online or allow you to keep track of the sites your children have visited. They
also can block newsgroups and chat areas which are inappropriate for children. You
can also prevent offensive pop-ups by using the pop-up blocker that is built in to
Internet Explorer. Keep in mind that no filtering software is 100% effective and cannot
replace your involvement in your children.s Internet use. Also check with your ISP
(Internet Service Provider), if they provide filtered content or safe connection packages.
4. Help your children to understand that some people lie online, and make them agree
to never meet alone with online friends in person, because they may not be who they
say they are, or may have bad intentions.
5. Help them to understand that they should never give out personal details like address,
phone number, passwords or messenger ID to online friends or send/publish pictures
of themselves, their friends or family, because anyone can abuse the information.
6. Encourage your children to chat only in monitored chat rooms and to never leave the
public area of that chat room. Insist they never go private.
7. Teach them to treat others as they want to be treated and to ignore bullies, block further
contact and report the bullying to the Webmaster, schools or other appropriate authorities.
8. Agree with them to never open attachments or files received from strangers or click on
links in E-mails or instant messaging. They might contain a virus or inappropriate
material.
9. Teach them not to believe everything they see or read online to be true. Encourage
them to be skeptical.
10. Explain to your kids that making illegal copies of music, games and other programs
is the same as stealing from a store.
The Electronic Transactions Act, 2063 (2008)
Date of Authentication and Publication
22 Mansir 2063 (December 8, 2006)
Act number 27 of the year 2063
An Act promulgated for Electronic Transactions
Preamble:
WHEREAS, it is expedient to make legal provisions for authentication and regularization
of the recognition, validity, integrity and reliability of generation, production, processing,
storage, communication and transmission system of electronic records by making the
transactions to be carried out by means of electronic data exchange or by any other means
of electronic communications, reliable and secured; and whereas, for controlling the acts
of unauthorized use of electronic records or of making alteration in such records through
the illegal manner, now, therefore, be it enacted by the House of Representatives in the
First Year of the issuance of the Proclamation of the House of Representatives, 2063 (2007).
Chapter - 1
Preliminary
1. Short Title, Extension and Commencement:
a. This Act may be called "The Electronic Transactions Act, 2063 (2008)."
b. This Act shall be deemed to have been commenced from 24 Bhadra 2063 (Sep.2,
2006).
c. This Act shall extend throughout Nepal and shall also apply to any person residing
anywhere by committing an offence in contravention to this Act.
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2. Definitions: Unless the subject or context otherwise requires, in this Acta. "Asymmetric Crypto System" means a system that creates a secured key-pair
consisting of a private key creating a digital signature and a public key to verify
the digital signature.
b. "License" means a license obtained pursuant to Sub-section (3) of Section 18.
c. "Originator" means a person who generates, stores or transmits electronic records,
and this term also includes a person who causes any other person to carry out
such functions:
Provided that it shall not include an intermediary.
d. "Computer" means an electro-magnetic, optical or other high-speed data processing
device or system, which performs logical, arithmetic and memory functions by manipulating
electro-magnetic or optical impulses, and also includes all acts of input, output, processing,
storage and computer software or communication facilities which are connected or related to the
computer in any computer system or computer network.
e. "Computer Database" means an information, knowledge and concept or presentation
of instructions, which are being prepared or have already been prepared in word,
image, voice or audio visual form in a formalized manner or which have been
produced by a computer, computer system or computer network, with a view to
use in a computer, computer system or computer network.
f. "Computer Network" means an interrelationship between two or more than two
computers having interconnection with each other or in contact or communication.
g. "Computer System" means a device or a group of devices, containing all computer
programmes including input and output support devices, electronic instructions,
input and output data that performs logical, arithmetic, data storage and retrieval,
communication including controlling functions.
h. "Computer Resource" means a computer, computer system, computer network,
data, computer database or software.
i. "Subscriber" means a person who has obtained a certificate under Subsection (3)
of Section 31.
j. "Key Pair" means a private key in an asymmetric crypto system and a pair of
public key, interconnected in a mathematics form with the private key which has
a code to verify digital signature by the public key to be created from the private
key.
k. "Data" means the presentation of information, knowledge, fact and concept or
instructions in any form, which are kept in a formalized manner in a computer
system or computer network and is intended for processing the same, or processed
or stored in a computer memory.
l. "Tribunal" means the Information Technology Tribunal formed pursuant to section
60.
m. "Private Key" means a key of any key pair used to create a digital signature.
Provisions Relating to Electronic Record and Digital Signature
3. Authencity of Electronic Record:
1. Any subscriber may, subject to the provisions of this section, authenticate to any
electronic record by his/her personal digital signature.
2. While authenticating the electronic record pursuant to Subsection (1), an act of
transforming such electronic record to other electronic record shall be effected
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by the use of asymmetric crypto system and hash function.
4. Legal Recognition of Electronic Record:
Where the prevailing law requires any information, documents, records or any other
matters to be kept in written or printed typewritten form, then, if such information,
document, record or the matter is maintained in an electronic form by fulfilling the
procedures as stipulated in this Act or the Rules made hereunder, such electronic record
shall also have legal validity.
5. Legal Recognition of Digital Signature:
Where the prevailing law requires any information, document, record or any other
matters to be certified by affixing signature or any document to be signed by any
person; then, if such information, documents, records or matters are certified by the
digital signature after fulfilling the procedures as stipulated in this Act or the Rules
made hereunder, such digital signature shall also have legal validity.
6. Electronic Records to be Kept Safely:
Where the prevailing law requires any information, document or record to be kept
safely for any specific period of time and if such information, document or record are
kept safely in an electronic form, by fulfilling the following condition, such information,
document or record shall have legal validity if that is,- (a) kept in an accessible condition
making available for a subsequent reference,
For details, see Electronic Transaction Act 2063.
1. Give the full forms of the following.
a. HLCIT b. E-business c. DOS d. IT
2. Answer the following questions.
a. What is cyber ethics?
b. Give the importance of cyber ethics.
c. Define computer crime. Why is it increasing day by day?
d. Define hacking with some hacking techniques?
e. When was cyber law of Nepal introduced? Why is it essential?
3. Give the technical terms.
a. The virtual environment created by the Internet, computers, computer networks.
b. The body that sets policy and procedures related to Electronic Transaction Act
of Nepal is called.
c. The moral principle related to cyber space.
d. Faked E-mail is also called......................................
e. A person directly or indirectly involved in hacking Web sites or information in
the cyber world.
4. Select the best option:
a. Cyber law of Nepal was introduced in:
i. 2061 BS
ii. 2063 BS
iii. Both (i) and (ii)
iv. Non of them
b. Cyber crime is:
i. Illegal access to a system
ii. Hacking
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iii. Denial of services
iv. All of above
c. Cyber ethics menas:
i. Principle of doing right
ii. Norms
iii. Both (i) and (ii)
iv. None of them
d. Malicious hacker is:
i. Cracker
ii. Hacker
iii. Both (i) and (ii)
iv. Non of them
E-learning Telemedicine (compatibility Mode)
Definitions
 E-learning
Usually a holistic term for learning via technology, “covering... Web based learning,
computer-based learning, virtual classrooms, and digital collaboration" (Erskine 2003).
 Learning Technology
Hardware or Software facilitating education, the “black box” view (Atherton 1999).
 VLE (Virtual Learning Environment)
Typically Web based synthesis of communication, collaboration and content dissemination
features.
 Online Learning
Study via the medium of the Web, or the Internet generally.
 Blended Learning (Distributed Learning)
Study context facilitated both by learning technology and traditional teaching methods.
 Ubiquitous Learning
The computer is an essential tool that must be available on demand and wherever we expect
to support learners." (Skill and Young 2002).
 Mobile Learning
Use of hand-held Portable Digital Assistants, Pagers, Laptops and other devices in the
context of WiLAN (Wireless Local Area Network) or Internet - via WAP (Wireless Access
Protocol) or GPRS (General Packet Radio Service).
e-learning Who and How
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Why E-learning?
Eliminating Learning divide:

Solving learning divide

Improving knowledge and learning content access

Effective teacher and student support

Implementing learning environment
Types of e-learning system:
a) Asynchronous E-Learning (student-centered approach to learning)
•
Self-paced virtual training
•
Computer-based Training (CBTs)
•
Wikis
•
Discussion boards
•
Blog sites
•
Frequently asked question pages
b) Synchronous Learning : (instructor-led online learning because it involves an interaction
between a student and an instructor )
Telemedicine
Telemedicine is a rapidly developing application of clinical medicine where medical
information is transferred through the phone or the Internet and sometimes other networks for the
purpose of consulting, and sometimes remote medical procedures or examinations.
Telemedicine may be as simple as two health professionals discussing a case over the telephone,
or as complex as using satellite technology and video-conferencing equipment to conduct a realMr. Ganesh chand
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time consultation between medical specialists in two different countries. Telemedicine generally
refers to the use of communications and information technologies for the delivery of clinical
care.
The terms e-health and telehealth are at times wrongly interchanged with telemedicine. Like the
terms "medicine" and "health care", telemedicine often refers only to the provision of clinical
services while the term telehealth can refer to clinical and non-clinical services such as medical
education, administration, and research. The term e-health is often, particularly in the UK and
Europe, used as an umbrella term that includes telehealth, electronic medical records, and other
components of health IT.
Telemedicine can be broken into two main categories: store-and-forward and interactive
services.
Store-and-forward telemedicine involves acquiring medical data (like medical images, biosignals
etc) and then transmitting this data to a doctor or medical specialist at a convenient time for
assessment offline. It does not require the presence of both parties at the same time. Dermatology
(cf: teledermatology), radiology, and pathology are common specialties that are conducive to
asynchronous telemedicine. A properly structured Medical Record preferably in electronic form
should be a component of this transfer. A key difference between traditional in-person patient
meetings and telemedicine encounters is the omission of an actual physical examination and
history. The store-and-forward process requires the clinician to rely on a history report and
audio/video information in lieu of a physical examination.
Interactive telemedicine services provide real-time interactions between patient and provider, to
include phone conversations, online communication and home visits. Many activities such as
history review, physical examination, psychiatric evaluations and ophthalmology assessments
can be conducted comparably to those done in traditional face-to-face visits. In addition,
“clinician-interactive” telemedicine services may be less costly than in-person clinical visits.
Intellectual Property
What is Intellectual Property?
Intellectual property refers to creations of the mind: inventions; literary and artistic works; and
symbols, names and images used in commerce. Intellectual property is divided into two
categories: Industrial Property includes patents for inventions, trademarks, industrial designs
and geographical indications.
Copyright covers literary works (such as novels, poems and plays), films, music, artistic works
(e.g., drawings, paintings, photographs and sculptures) and architectural design. Rights related to
copyright include those of performing artists in their performances, producers of phonograms in
their recordings, and broadcasters in their radio and television programs.
What are intellectual property rights?
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Intellectual property rights are like any other property right. They allow creators, or owners, of
patents, trademarks or copyrighted works to benefit from their own work or investment in a
creation.
These rights are outlined in Article 27 of the Universal Declaration of Human Rights, which
provides for the right to benefit from the protection of moral and material interests resulting from
authorship of scientific, literary or artistic productions. The importance of intellectual property
was first recognized in the Paris Convention for the Protection of Industrial Property (1883) and
the Berne Convention for the Protection of Literary and Artistic Works (1886). Both treaties are
administered by the World Intellectual Property Organization (WIPO).
Why promote and protect intellectual property?
There are several compelling reasons. First, the progress and well-being of humanity rest on its
capacity to create and invent new works in the areas of technology and culture. Second, the legal
protection of new creations encourages the commitment of additional resources for further
innovation. Third, the promotion and protection of intellectual property spurs economic growth,
creates new jobs and industries, and enhances the quality and enjoyment of life.
An efficient and equitable intellectual property system can help all countries to realize
intellectual property’s potential as a catalyst for economic development and social and cultural
well-being. The intellectual property system helps strike a balance between the interests of
innovators and the public interest, providing an environment in which creativity and invention
can flourish, for the benefit of all.
What is a Patent?
A patent is an exclusive right granted for an invention –a product or process that provides a new
way of doing something, or that offers a new technical solution to a problem. A patent provides
patent owners with protection for their inventions. Protection is granted for a limited period,
generally 20 years.
Why are patents necessary?
Patents provide incentives to individuals by recognizing their creativity and offering the
possibility of material reward for their marketable inventions. These incentives encourage
innovation, which in turn enhances the quality of human life.
What is a trademark?
A trademark is a distinctive sign that identifies certain goods or services produced or provided by
an individual or a company. Its origin dates back to ancient times when craftsmen reproduced
their signatures, or “marks”, on their artistic works or products of a functional or practical nature.
Over the years, these marks have evolved into today’s system of trademark registration and
protection. The system helps consumers to identify and purchase a product or service based on
whether its specific characteristics and quality – as indicated by its unique trademark– meet their
needs.
What do trademarks do?
Trademark protection ensures that the owners of marks have the exclusive right to use them to
identify goods or services, or to authorize others to use them in return for payment. The period of
protection varies, but a trademark can be renewed indefinitely upon payment of the
corresponding fees. Trademark protection is legally enforced by courts that, in most systems,
have the authority to stop trademark infringement. In a larger sense, trademarks promote
initiative and enterprise worldwide by rewarding their owners with recognition and financial
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profit. Trademark protection also hinders the efforts of unfair competitors, such as counterfeiters,
to use similar distinctive signs to market inferior or different products or services. The system
enables people with skill and enterprise to produce and market goods and services in the fairest
possible conditions, thereby facilitating international trade.
What are Copyright and Related Rights?
Copyright laws grant authors, artists and other creators protection for their literary and artistic
creations, generally referred to as “works”. A closely associated field is “related rights” or rights
related to copyright that encompass rights similar or identical to those of copyright, although
sometimes more limited and of shorter
duration. The beneficiaries of related rights are:
 performers (such as actors and musicians) in their performances;
 producers of phonograms (for example, compact discs) in their sound recordings;
 and broadcasting organizations in their radio and television programs.
Works covered by copyright include, but are not limited to: novels, poems, plays, reference
works, newspapers, advertisements, computer programs, databases, films, musical compositions,
choreography, paintings, drawings, photographs, sculpture, architecture, maps and technical
drawings.
What rights do copyright and related rights provide?
The creators of works protected by copyright, and their heirs and successors (generally referred
to as “right holders”), have certain basic rights under copyright law. They hold the exclusive
right to use or authorize others to use the work on agreed terms. The right holder(s) of a work
can authorize or prohibit: its reproduction in all forms, including print form and sound recording;
its public performance and communication to the public; its broadcasting; its translation into
other languages; and its adaptation, such as from a novel to a screenplay for a film. Similar rights
of, among others, fixation (recording) and reproduction are granted under related rights.
Many types of works protected under the laws of copyright and related rights require mass
distribution, communication and financial investment for their successful dissemination (for
example, publications, sound recordings and films). Hence, creators often transfer these rights to
companies better able to develop and market the works, in return for compensation in the form of
payments and/or royalties (compensation based on a percentage of revenues generated by the
work).
The economic rights relating to copyright are of limited duration – WIPO treaties – beginning
with the creation and fixation of the work, and lasting for not less than 5 years after the creator’s
death. National laws may establish longer terms of protection. This term of protection enables
both creators and their heirs and successors to benefit financially for a reasonable period of time.
Related rights enjoy shorter terms, normally 50 years after the performance; recording or
broadcast has taken place. Copyright and the protection of performers also include moral rights,
meaning the right to claim authorship of a work, and the right to oppose changes to the work that
could harm the creator’s reputation. Rights provided for under copyright and related rights laws
can be enforced by right holders through a variety of methods and fora, including civil action
suits, administrative remedies and criminal prosecution. Injunctions, orders requiring destruction
of infringing items, inspection orders, among others, are used to enforce these rights.
What are the benefits of protecting copyright and related rights?
Copyright and related rights protection is an essential component in fostering human creativity
and innovation. Giving authors, artists and creators incentives in the form of recognition and fair
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economic reward increases their activity and output and can also enhance the results. By
ensuring the existence and enforceability of rights, individuals and companies can more easily
invest in the creation, development and global dissemination of their works. This, in turn, helps
to increase access to and enhance the enjoyment of culture, knowledge and entertainment the
world over, and also stimulates economic and social development.
Multimedia and Its Application
Background
With the development of new technologies it has become possible to use a large screen projector
for lectures. The educators can use a multimedia performance as a new and powerful tool for
the presentation of educational information instead of a monotonous chalk talk. To adopt this
multimedia learning environment it is necessary to solve two main problems: the creation of a
specialized multimedia lecture room and equipping it with appropriate hardware and software for
designing and delivering lectures. The aim of multimedia is not only used in education. It is used
in almost all the fields such as film industries, animations etc.
Understanding Multimedia
Amedium is a way of communicating information such as speech or text. Multimedia is the use
of more than one unique medium at a time. The term new media is used to describe the
combination of multimedia programming and communication technologies that enable
multimedia to be distributed in different ways such as disk, via the Internet or over television.
Therefore multimedia is defined as a media that uses multiple forms of information content
and information processing (e.g. text, audio, graphics, animation, video, interactivity) to
inform or entertain the user/audience. Multimedia also refers to the use of (but not limited
to) electronic media to store and experience multimedia content. In summary, multiple
media is multimedia.
Hypermedia
The term multimedia has been coined to describe the environment that allows users to click
on one type of media to navigate to the same or other type of media. You have probably
encountered various type of hypermedia tools while visiting Web sites and different animated
pop up windows and e-advertsing etc.
Applications of Multimedia
As such multimedia programs are used in a variety of ways. Some of the applications are
discussed below.
a) Multimedia is commonly used in schools where students use CD-ROM or DVD based
reference materials and tutorials and use the Internet to collaborate with students at
other locations.
b) In the workplace companies use multimedia programs to train the employees.
These training programs are called Computer Based Training (CBT).
c) Multimedia is used in cartoon animation and film industries.
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d) Multimedia is frequently used at home whether on a PC, television or the Internet. Home
users consume a wide variet of multimedia products for entertainment and learning. Such
feature of entertaining and learning is sometime called edutainment.
Advantages of Multimedia
So far we discussed about multimedia, its scope and applications. In this section, we will
highlight about the advantages of multimedia.
a) Simulation of air combat, space shuttle flight are the use of Multimedia.
b) Multimedia enhances the teaching learning process by making it more interactive.
c) Multimedia assists in teaching thorough animation so that students can understand
d) easily.
e) Now, it is possible to get virtual classes at your home as a part of distance learning.
f) Multimedia is used in film industry to make a presentation realistie.
Technologies that Support New Media
a) A wide range of new technologies have been created to support multimedia on CDROM, DVD, and Internet. These technologies enable developers to create sophisticated
contents using almost any type of medium and allow the end user to play the contents.
b) The real audio and real video formats are the current standards for streaming audio
and video played over an Internet connection.
c) The MPEG (Motion Picture Expert Group), AVI , and QuickTime formats are new
technologies that allow full-motion video files to be compressed and played back the on
PC whether from CD or Internet.
d) Animation are developed using micromedia flash and 3 .D animation such as MAYA.
e) Distributing Media Contents, Currently, multimedia content is typically delivered to users
by one of three means: CD-ROM or DVD-ROM or Internet or some sort of network
connection or television. Of course, each delivery method has its own set of unique
strengths and weaknesses. Each delivery method affects the product.s ability to use
certain technologies.
Careers in Multimedia
Careers in multimedia are as varied and as numerous as multimedia products. Multimedia
work is usually done by teams. List of some professions are given below.
a) Art director: S/he directs the creation of all art for the project. This work involves a variety
of original media, which are changed to digital from for manipulation on the modern artist.s
canvas, the computer.
b) Animator: Animators use their finished work by photographing models and sculptures or
hand-drawn and painted pictures. 2-D and 3-D softwares are used specially for animation.
c) Graphic Designer: S/he designs and creates the products using graphics software such as
Photoshop.
d) Videographer: S/he creates the video footage that interfaces with the interactive technology
of the product. Video is often the most complex, time consuming and resource demanding
medium to create.
e) Technical lead: S/he ensures that the technologies and the process of a project works and
that it accommodates all project components and media.
Electronic Conferencing Tools
Data Conferencing
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

Also called .white boarding..
Share diagrams or documents and revise them in real time while connected over the
Internet or an intranet.
Voice Conferencing
 In the past voice conferencing place over speak erphones and other telephone setups.
 Extensions are available for web browsers.
 Internet telephone software.
 Can be combined with data conferencing for more effective collaboration.
 Real time interactive audio and video capabilities.
 Networked PCs over the Internet.
 Closed circuit television.
 Most economic and effective method of video conferencing is desktop video
conferencing.
 Saves money and travel time, and is an excellent tool for meetings.
Desktop Video Conference
An enterprise collaboration tool that enables realtime video/audio conferences among (1)
networked PCs, known as desktop video conference or (2) networked conference rooms
or auditoriums in different locations called tele conferences.
Discussion Forums
 Post messages and respond to the messages of others
 Encourage participation and share the contribution of everyone
Chat Systems
 Carry on a text-based conversation, usually in real time
 Can be recorded and reviewed at a later time
 Give participants a degree of anonymity and encourage participation
Electronic Meeting Systems
 Facilitates decision-making in meetings
 Example: voting.
 Makes group communications easier
 Protects the anonymity of participants
 Provides a recording of group discussions
Virtual Reality
Virtual reality is an artificial environment that is created with software and presented to
the user in such a way that the user suspends disbelief and accepts it as a real environment. On a
computer, virtual reality is primarily experienced through two of the five senses: sight and sound.
The simplest form of virtual reality is a 3-D image that can be explored interactively at a
personal computer, usually by manipulating keys or the mouse so that the content of the image
moves in some direction or zooms in or out. More sophisticated efforts involve such approaches
as wrap-around display screens, actual rooms augmented with wearable computers, and haptics
devices that let you feel the display of images.
Virtual reality can be divided into:
 The simulation of a real environment for training and education.
 The development of an imagined environment for a game or interactive story.
Popular products for creating virtual reality effects on personal computers include Bryce,
Extreme 3D, Ray Dream Studio, TrueSpace, 3D Studio MAX, and Visual Reality. The
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Virtual Reality Modelling Language allows the creator to specify images and the rules for
their display and interaction using textual language statements.
Computer-based virtual reality has been a common part of modern popular culture and
technology for decades now. It is used both as a tool and also for entertainment purposes. The
technology has many applications, although its importance may occasionally need some
clarification.
Virtual Reality Basics
1. The basic concept of virtual reality is sensual immersion in a computer generated
environment. This may include sight, sound, touch, and smell. This is basically a kind
of controllable reality simulation.
Virtual Architecture
2. Architectural visualization is one of the applied uses of virtual reality today. A virtual
walk-through of a building design, prior to its construction, can actually help architects
and their clients better understand what the building will actually be like to inhabit
once built.
Pilot Training
3. The training of pilots for the aviation industry is another popular use of virtual reality
today. This is especially beneficial to airline pilots flying simulated commercial jetliners,
as it offers the ability to practice something that is relatively risky and costly with an
actual plane. Train conductors in Japan also train with virtual reality simulators.
1. Fill in the blanks.
a. MPGE stands for ..............................
b. The practice of using more than one medium at a time is called..............................
c. The............................. file format is commonly used for full motion video files.
d. ............................. uses multimedia technologies to enable students to take class
room.
e. CBT stands for..............................
f. The technologies that deliver the contents of multimedia are CD-ROM, DVD
ROM and ..............................
2. Multiple choice.
a. The additional software required to play multimedia elements on a Webpage are
called ?
i. Browser ii. Compiler iii. Plug-ins iv. Media player
b. In education, multimedia is used to produce CBTs. CBT stands for.
i. Computer Based Training ii. Computer Based Teaching
iii. Training by computer iv. All of the above
c. Find the odd one out
i. Text ii. Animation iii. Sound iv. Mail merge
d. Multimedia includes which of the following facilities.
i. Audio ii. Video iii. Audio, Video and Animation. iv. Both a. and b.
e. 3D titles in games and movies are made using this technique.
i. MS-Word ii. MS-Excel iii. Internet iv. Multimedia
3. Answer the following questions.
a. What benefits can interactive multimedia bring to education?
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b. What is multimedia? Give its importance.
c. List any four application areas of multimedia.
d. What are the three key hardware components in a multimedia capable computer?
4. Write the full form of.
MPEG
GIF
JPEG
VRML
BMP
AVI
CDROM
PDA
DVD
CBT
Definitions
 E-learning
Usually a holistic term for learning via technology, “covering... Web based learning,
computer-based learning, virtual classrooms, and digital collaboration" (Erskine 2003).
 Learning Technology
Hardware or Software facilitating education, the “black box” view (Atherton 1999).
 VLE (Virtual Learning Environment)
Typically Web based synthesis of communication, collaboration and content dissemination
features.
 Online Learning
Study via the medium of the Web, or the Internet generally.
 Blended Learning (Distributed Learning)
Study context facilitated both by learning technology and traditional teaching methods.
 Ubiquitous Learning
The computer is an essential tool that must be available on demand and wherever we expect
to support learners." (Skill and Young 2002).
 Mobile Learning
Use of hand-held Portable Digital Assistants, Pagers, Laptops and other devices in the
context of WiLAN (Wireless Local Area Network) or Internet - via WAP (Wireless Access
Protocol) or GPRS (General Packet Radio Service).
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e-learning Who and How
Why E-learning?
Eliminating Learning divide:

Solving learning divide

Improving knowledge and learning content access

Effective teacher and student support

Implementing learning environment
Types of e-learning system:
c) Asynchronous E-Learning (student-centered approach to learning)
•
Self-paced virtual training
•
Computer-based Training (CBTs)
•
Wikis
•
Discussion boards
•
Blog sites
•
Frequently asked question pages
d) Synchronous Learning : (instructor-led online learning because it involves an interaction
between a student and an instructor )
Telemedicine
Telemedicine is a rapidly developing application of clinical medicine where medical
information is transferred through the phone or the Internet and sometimes other networks for the
purpose of consulting, and sometimes remote medical procedures or examinations.
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Telemedicine may be as simple as two health professionals discussing a case over the telephone,
or as complex as using satellite technology and video-conferencing equipment to conduct a realtime consultation between medical specialists in two different countries. Telemedicine generally
refers to the use of communications and information technologies for the delivery of clinical
care.
The terms e-health and telehealth are at times wrongly interchanged with telemedicine. Like the
terms "medicine" and "health care", telemedicine often refers only to the provision of clinical
services while the term telehealth can refer to clinical and non-clinical services such as medical
education, administration, and research. The term e-health is often, particularly in the UK and
Europe, used as an umbrella term that includes telehealth, electronic medical records, and other
components of health IT.
Telemedicine can be broken into two main categories: store-and-forward and interactive
services.
Store-and-forward telemedicine involves acquiring medical data (like medical images, biosignals
etc) and then transmitting this data to a doctor or medical specialist at a convenient time for
assessment offline. It does not require the presence of both parties at the same time. Dermatology
(cf: teledermatology), radiology, and pathology are common specialties that are conducive to
asynchronous telemedicine. A properly structured Medical Record preferably in electronic form
should be a component of this transfer. A key difference between traditional in-person patient
meetings and telemedicine encounters is the omission of an actual physical examination and
history. The store-and-forward process requires the clinician to rely on a history report and
audio/video information in lieu of a physical examination.
Interactive telemedicine services provide real-time interactions between patient and provider, to
include phone conversations, online communication and home visits. Many activities such as
history review, physical examination, psychiatric evaluations and ophthalmology assessments
can be conducted comparably to those done in traditional face-to-face visits. In addition,
“clinician-interactive” telemedicine services may be less costly than in-person clinical visits.
Intellectual Property
What is Intellectual Property?
Intellectual property refers to creations of the mind: inventions; literary and artistic works; and
symbols, names and images used in commerce. Intellectual property is divided into two
categories: Industrial Property includes patents for inventions, trademarks, industrial designs
and geographical indications.
Copyright covers literary works (such as novels, poems and plays), films, music, artistic works
(e.g., drawings, paintings, photographs and sculptures) and architectural design. Rights related to
copyright include those of performing artists in their performances, producers of phonograms in
their recordings, and broadcasters in their radio and television programs.
What are intellectual property rights?
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Intellectual property rights are like any other property right. They allow creators, or owners, of
patents, trademarks or copyrighted works to benefit from their own work or investment in a
creation.
These rights are outlined in Article 27 of the Universal Declaration of Human Rights, which
provides for the right to benefit from the protection of moral and material interests resulting from
authorship of scientific, literary or artistic productions. The importance of intellectual property
was first recognized in the Paris Convention for the Protection of Industrial Property (1883) and
the Berne Convention for the Protection of Literary and Artistic Works (1886). Both treaties are
administered by the World Intellectual Property Organization (WIPO).
Why promote and protect intellectual property?
There are several compelling reasons. First, the progress and well-being of humanity rest on its
capacity to create and invent new works in the areas of technology and culture. Second, the legal
protection of new creations encourages the commitment of additional resources for further
innovation. Third, the promotion and protection of intellectual property spurs economic growth,
creates new jobs and industries, and enhances the quality and enjoyment of life.
An efficient and equitable intellectual property system can help all countries to realize
intellectual property’s potential as a catalyst for economic development and social and cultural
well-being. The intellectual property system helps strike a balance between the interests of
innovators and the public interest, providing an environment in which creativity and invention
can flourish, for the benefit of all.
What is a Patent?
A patent is an exclusive right granted for an invention –a product or process that provides a new
way of doing something, or that offers a new technical solution to a problem. A patent provides
patent owners with protection for their inventions. Protection is granted for a limited period,
generally 20 years.
Why are patents necessary?
Patents provide incentives to individuals by recognizing their creativity and offering the
possibility of material reward for their marketable inventions. These incentives encourage
innovation, which in turn enhances the quality of human life.
What is a trademark?
A trademark is a distinctive sign that identifies certain goods or services produced or provided by
an individual or a company. Its origin dates back to ancient times when craftsmen reproduced
their signatures, or “marks”, on their artistic works or products of a functional or practical nature.
Over the years, these marks have evolved into today’s system of trademark registration and
protection. The system helps consumers to identify and purchase a product or service based on
whether its specific characteristics and quality – as indicated by its unique trademark– meet their
needs.
What do trademarks do?
Trademark protection ensures that the owners of marks have the exclusive right to use them to
identify goods or services, or to authorize others to use them in return for payment. The period of
protection varies, but a trademark can be renewed indefinitely upon payment of the
corresponding fees. Trademark protection is legally enforced by courts that, in most systems,
have the authority to stop trademark infringement. In a larger sense, trademarks promote
initiative and enterprise worldwide by rewarding their owners with recognition and financial
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profit. Trademark protection also hinders the efforts of unfair competitors, such as counterfeiters,
to use similar distinctive signs to market inferior or different products or services. The system
enables people with skill and enterprise to produce and market goods and services in the fairest
possible conditions, thereby facilitating international trade.
What are Copyright and Related Rights?
Copyright laws grant authors, artists and other creators protection for their literary and artistic
creations, generally referred to as “works”. A closely associated field is “related rights” or rights
related to copyright that encompass rights similar or identical to those of copyright, although
sometimes more limited and of shorter
duration. The beneficiaries of related rights are:
 performers (such as actors and musicians) in their performances;
 producers of phonograms (for example, compact discs) in their sound recordings;
 and broadcasting organizations in their radio and television programs.
Works covered by copyright include, but are not limited to: novels, poems, plays, reference
works, newspapers, advertisements, computer programs, databases, films, musical compositions,
choreography, paintings, drawings, photographs, sculpture, architecture, maps and technical
drawings.
What rights do copyright and related rights provide?
The creators of works protected by copyright, and their heirs and successors (generally referred
to as “right holders”), have certain basic rights under copyright law. They hold the exclusive
right to use or authorize others to use the work on agreed terms. The right holder(s) of a work
can authorize or prohibit: its reproduction in all forms, including print form and sound recording;
its public performance and communication to the public; its broadcasting; its translation into
other languages; and its adaptation, such as from a novel to a screenplay for a film. Similar rights
of, among others, fixation (recording) and reproduction are granted under related rights.
Many types of works protected under the laws of copyright and related rights require mass
distribution, communication and financial investment for their successful dissemination (for
example, publications, sound recordings and films). Hence, creators often transfer these rights to
companies better able to develop and market the works, in return for compensation in the form of
payments and/or royalties (compensation based on a percentage of revenues generated by the
work).
The economic rights relating to copyright are of limited duration – WIPO treaties – beginning
with the creation and fixation of the work, and lasting for not less than 5 years after the creator’s
death. National laws may establish longer terms of protection. This term of protection enables
both creators and their heirs and successors to benefit financially for a reasonable period of time.
Related rights enjoy shorter terms, normally 50 years after the performance; recording or
broadcast has taken place. Copyright and the protection of performers also include moral rights,
meaning the right to claim authorship of a work, and the right to oppose changes to the work that
could harm the creator’s reputation. Rights provided for under copyright and related rights laws
can be enforced by right holders through a variety of methods and fora, including civil action
suits, administrative remedies and criminal prosecution. Injunctions, orders requiring destruction
of infringing items, inspection orders, among others, are used to enforce these rights.
What are the benefits of protecting copyright and related rights?
Copyright and related rights protection is an essential component in fostering human creativity
and innovation. Giving authors, artists and creators incentives in the form of recognition and fair
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economic reward increases their activity and output and can also enhance the results. By
ensuring the existence and enforceability of rights, individuals and companies can more easily
invest in the creation, development and global dissemination of their works. This, in turn, helps
to increase access to and enhance the enjoyment of culture, knowledge and entertainment the
world over, and also stimulates economic and social development.
E-BUSINES
and
E-Commerce
Electronic Commerce - Overview
The elements of Commerce
n When you get down to the actual elements of commerce and commercial transactions, we need following
list of elements of for typical commerce activities. In this case, the activity is the sale if some product by a
retailor to a consumer.
n If you would like to sell something to a consumer, at the very core of the matter is the something itself. You
must have a product or service to offer.
n You must also have a place from which to sell your product. For example telephone no can be a place.
n You need to figure out a way to get people to come to your place. This process is known as “Marketing”.
n
n
n
We must have the following elements to conduct e-commerce:
A product
A place to sell the product- in e-commerce, a web site displays the products in some way and acts as the
place.
n A way to get people to come to your web sites
n A way to accept orders-normally on on-line form of some sort
n A way to accept money- normally a merchant account handling credit card payments. This piece requires a
secure ordering page and a connection to a bank. Or you may use traditional billing techniques either online
or through the mail
We must have the following elements to conduct e-commerce:
n A fulfillment facility to ship products to customers(often outsource-able). In the case of Software and
Information, however, fulfillment can occur over the web through a file download mechanism.
n A way to accept returns
n A way to handle warranty claims if necessary
n A way to provide customer service (often through email, on-line forms, on-line knowledge bases and FAQs
Etc)
n In addition, there is often a strong desire to integrate other business functions or practices into the ecommerce offering. An extremely simple example –you might want to be able to show the customer the
exact status of an order.
n The Lure of e-commerce
n
The following list summarizes what might be called the “The lure of e-commerce”
n
Lower transaction costs- if an e-commerce site is implemented well, the web can significantly lower both
order-taking costs up front and customer services cost after the sale by automating process.
n
Large purchase per transaction – Amazon offers a feature that no normal store offers. When you read the
description of a book, you also can see “ what other people who order this book also purchased”. That is,
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you can see the related books that people are actually buying. Because of the feature like these it is
common for people to buy more books that might buy at a normal bookstore.
n
Integration into business cycle: A web site that is well integrated into the business cycle can offer customer
more information that previously available. For example, if Dell tracks each computer through the
manufacturing and shipping process, customer can see exactly where their order is at any time.
What is Electronic Commerce?
n EC defined from these perspectives
 Communications
 Business process
 Service
 Online
 Collaborations
 Community
n Electronic commerce encompasses the entire online process of developing, marketing, selling, delivering,
servicing, and paying for products and services transacted on internetworked, global marketplaces of
customers, with the support of a worldwide network of business partners.
n Electronic Commerce (EC) from communication perspective: e-commerce is a delivery of information,
products/services, or payments via telephone line, computer network or any other means.
n E-commerce from business process: E-Commerce is the application of technology towards automation of
business transaction and workflows.
n E-Commerce from service perspective: E-Commerce is a tool that addresses the desire of firms, consumers,
and management to cut services costs while improving the quality of goods and increasing the speed of
service delivery.
n From online perspective, e-commerce provides the capability of buying and selling products and
information on the Internet and other services.
What E-commerce offers?
People can shop in different ways: Traditional mail order companies introduced the concept of shopping from home
in your pajamas, and e-commerce offers this same luxury. New feature that web site offers includes:
n The ability to build an order in several days
n
The ability to configure products and see actual price
n
The ability to compare prices between multiple vendors easily
n
The ability to easily build complicated custom orders
n
The ability to search large catalogs easily
Improved customer interactions: with automated tools it is possible to interact with customer in richer ways at
virtually no cost. For example, the customer might get an e-mail when the order is confirmed, when the order is
shipped and after the order arrives.
What is Electronic Business?
n E-business is a broader definition of EC that includes not just the buying and selling of goods and services,
but also
 Servicing customers
 Collaborating with business partners
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 Conducting electronic transactions within an organization
n
E-Business = E-Commerce + CRM + SCM
n
CRM = Customer Relationship Management
n
SCM = Supply Chain Management
Classification of EC by the Nature of the Transaction
n Business-to-business (B2B) : EC model in which all of the participants are businesses or other
organizations
n
Business-to-consumer (B2C): EC model in which businesses sell to individual shoppers
n
Business-to-business-to-consumer (B2B2C): EC model in which a business provides some product or
service to a client business; the client business maintains its own customers, to whom the product or service
is provided
Classification of EC by the Nature of the Transaction (cont.)
n Consumer-to-business(C2B): individuals who use the Internet to sell products or services to organizations
and /or seek sellers to bid on products or services they need
n
Consumer-to-consumer (C2C) : consumers sell directly to other consumers
n
Consumer-to-business(C2B): individuals who use the Internet to sell products or services to organizations
and /or seek sellers to bid on products or services they need
n
Consumer-to-consumer (C2C) : consumers sell directly to other consumers
Regulatory status of e-commerce in Nepal
Electronic Transaction Act 2061 BS(2004 AD)
Regulatory status of e-commerce in Nepal
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Network and Data Communication
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Mobile Commerce
Some definition
Definition:
“E-commerce over mobile devices” – (Robinson-Humphreys)
“The use of mobile handheld devices to communicate, interact via an always –on high speed connection to the
internet” – (Forrester)
n Examples of M-commerce
 Purchasing movie Tickets
 Purchasing airlines Tickets
 Hotel Booking and reservation
 Restaurant booking and reservation
 Searching for goods and services
 Information customers for payback schedules and pay amount
 Agenda of meeting
M-commerce services
n Information –Based services
 Instant messaging
 E-mail
 Searching for movies using cell phone or handheld PDAs.

n
Eg. Google in AirTel, Euddy Etc.
Transaction-based services
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 Purchasing stocks, concert tickets, music or games
 Searching for best prices for an item using a cell phone and buying it in a physical store or on the
web.
n
Personalized services
 Services that anticipate what a customer wants based on that person’s location or data profiles,
such as update airlines flight information.
M-Commerce Vs E-commerce
Technology
E-commerce
M-commerce
Device
PC
Smart phone’s, PDAs
OS
Ms-Windows, Linux, Unitx
Symbian(EPOC), PlamOS,
Pocket PC
Presentation Standards
HTML
HTML, WML, i-mode
Browser
IE, Netscape, Opera
Phone.com, Nokia browser,
MS-Mobile Explorer and Micro
browsers
Bearer Networks
TCP/IP, Fixed Wire line
Internet
GSM, GPRS, CDMA,
CDPD(Cellular digital Pocket
data)
Application Areas
n
Finance services
n
Mobile banking
n
Wireless e-payment system
n
Micropayment
n
Wireless bill payment
M-commerce Challenges, Obstacles, Limitations and issues
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Data transfer speed of cellular networks is comparatively slow, resulting in higher cost to customer.
Cellular phones have limited memory and power suppliers. More web sites need to be designed specially for small
wireless devices in account of its small screen and keyboard awkward to use. In case of payment through mobile is
still unsecured.
M-commerce obstacles
n Complex standardization process
n
Multitude of network technologies
n
Infrastructure investment
n
Demand and uncertainty
n
Slow than anticipated WAP adoption
The Benefits of EC
n Benefits to Organizations
 Expands the marketplace to national and international markets
 Decreases the cost of creating, processing, distributing, storing and retrieving paper-based
information
 Allows reduced inventories and overhead by facilitating pull-type supply chain management
The pull-type processing allows for customization of products and services which provides
competitive advantage to its implementers
n
Benefits to Organizations
 Reduces the time between the outlay of capital and the receipt of products and services
 Supports business processes reengineering (BPR) efforts
 Lowers telecommunications cost - the Internet is much cheaper than value added networks
(VANs)
Benefits of EC (cont.)
n Benefits to consumers
 Enables consumers to shop or do other transactions 24 hours a day, all year round from almost any
location( 7× 24) (52 × 24) (365 × 24)
 Provides consumers with more choices
 Provides consumers with less expensive products and services by allowing them to shop in many
places and conduct quick comparisons
 Allows quick delivery of products and services (in some cases) especially with digitized products
n
Benefits to consumers
 Consumers can receive relevant and detailed information in seconds, rather than in days or weeks
 Makes it possible to participate in virtual auctions
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 Allows consumers to interact with other consumers in electronic communities and exchange ideas
as well as compare experiences
 Facilitates competition, which results in substantial discounts
n
Benefits to society
 Enables more individuals to work at home, and to do less traveling for shopping, resulting in less
traffic on the roads, and lower air pollution
 Allows some merchandise to be sold at lower prices, benefiting less affluent people
 Enables people in Third World countries and rural areas to enjoy products and services which
otherwise are not available to them
 Facilitates delivery of public services at a reduced cost, increases effectiveness, and/or improves
quality
The Limitations of EC
n Technical limitations
 There is a lack of universally accepted standards for quality, security, and reliability
 The telecommunications bandwidth is insufficient
 Software development tools are still evolving
 There are difficulties in integrating the Internet and EC software with some existing (especially
legacy) applications and databases.
 Special Web servers in addition to the network servers are needed (added cost).
 Internet accessibility is still expensive and/or inconvenient
Multimedia and Its Application
Background
With the development of new technologies it has become possible to use a large screen projector for lectures. The
educators can use a multimedia performance as a new and powerful tool for the presentation of educational
information instead of a monotonous chalk talk. To adopt this multimedia learning environment it is necessary to
solve two main problems: the creation of a specialized multimedia lecture room and equipping it with appropriate
hardware and software for designing and delivering lectures. The aim of multimedia is not only used in education. It
is used in almost all the fields such as film industries, animations etc.
Understanding Multimedia
Amedium is a way of communicating information such as speech or text. Multimedia is the use of more than one
unique medium at a time. The term new media is used to describe the combination of multimedia programming and
communication technologies that enable
multimedia to be distributed in different ways such as disk, via the Internet or over television.
Therefore multimedia is defined as a media that uses multiple forms of information content
and information processing (e.g. text, audio, graphics, animation, video, interactivity) to
inform or entertain the user/audience. Multimedia also refers to the use of (but not limited
to) electronic media to store and experience multimedia content. In summary, multiple
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media is multimedia.
Hypermedia
The term multimedia has been coined to describe the environment that allows users to click
on one type of media to navigate to the same or other type of media. You have probably
encountered various type of hypermedia tools while visiting Web sites and different animated
pop up windows and e-advertsing etc.
Applications of Multimedia
As such multimedia programs are used in a variety of ways. Some of the applications are
discussed below.
b) Multimedia is commonly used in schools where students use CD-ROM or DVD based reference materials
and tutorials and use the Internet to collaborate with students at
other locations.
b) In the workplace companies use multimedia programs to train the employees. These training
programs are called Computer Based Training (CBT).
c) Multimedia is used in cartoon animation and film industries.
d) Multimedia is frequently used at home whether on a PC, television or the Internet. Home users consume a
wide variet of multimedia products for entertainment and learning. Such feature of entertaining and
learning is sometime called edutainment.
Advantages of Multimedia
So far we discussed about multimedia, its scope and applications. In this section, we will
highlight about the advantages of multimedia.
g) Simulation of air combat, space shuttle flight are the use of Multimedia.
h) Multimedia enhances the teaching learning process by making it more interactive.
i) Multimedia assists in teaching thorough animation so that students can understand
j) easily.
k) Now, it is possible to get virtual classes at your home as a part of distance learning.
l) Multimedia is used in film industry to make a presentation realistie.
Technologies that Support New Media
f) A wide range of new technologies have been created to support multimedia on CDROM, DVD, and Internet. These technologies enable developers to create sophisticated contents using
almost any type of medium and allow the end user to play the contents.
g) The real audio and real video formats are the current standards for streaming audio
and video played over an Internet connection.
h) The MPEG (Motion Picture Expert Group), AVI , and QuickTime formats are new technologies that allow
full-motion video files to be compressed and played back the on PC whether from CD or Internet.
i) Animation are developed using micromedia flash and 3 .D animation such as MAYA.
j) Distributing Media Contents, Currently, multimedia content is typically delivered to users by one of three
means: CD-ROM or DVD-ROM or Internet or some sort of network connection or television. Of course,
each delivery method has its own set of unique strengths and weaknesses. Each delivery method affects the
product.s ability to use certain technologies.
Careers in Multimedia
Careers in multimedia are as varied and as numerous as multimedia products. Multimedia
work is usually done by teams. List of some professions are given below.
f) Art director: S/he directs the creation of all art for the project. This work involves a variety of original media,
which are changed to digital from for manipulation on the modern artist.s canvas, the computer.
g) Animator: Animators use their finished work by photographing models and sculptures or hand-drawn and
painted pictures. 2-D and 3-D softwares are used specially for animation.
h) Graphic Designer: S/he designs and creates the products using graphics software such as Photoshop.
i) Videographer: S/he creates the video footage that interfaces with the interactive technology of the product.
Video is often the most complex, time consuming and resource demanding medium to create.
j) Technical lead: S/he ensures that the technologies and the process of a project works and that it accommodates
all project components and media.
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Electronic Conferencing Tools
Data Conferencing
 Also called .white boarding..
 Share diagrams or documents and revise them in real time while connected over the Internet or an intranet.
Voice Conferencing
 In the past voice conferencing place over speak erphones and other telephone setups.
 Extensions are available for web browsers.
 Internet telephone software.
 Can be combined with data conferencing for more effective collaboration.
 Real time interactive audio and video capabilities.
 Networked PCs over the Internet.
 Closed circuit television.

Most economic and effective method of video conferencing is desktop video conferencing.
 Saves money and travel time, and is an excellent tool for meetings.
Desktop Video Conference
An enterprise collaboration tool that enables realtime video/audio conferences among (1)
networked PCs, known as desktop video conference or (2) networked conference rooms
or auditoriums in different locations called tele conferences.
Discussion Forums
 Post messages and respond to the messages of others
 Encourage participation and share the contribution of everyone
Chat Systems
 Carry on a text-based conversation, usually in real time
 Can be recorded and reviewed at a later time
 Give participants a degree of anonymity and encourage participation
Electronic Meeting Systems
 Facilitates decision-making in meetings
 Example: voting.
 Makes group communications easier
 Protects the anonymity of participants
 Provides a recording of group discussions
Virtual Reality
Virtual reality is an artificial environment that is created with software and presented to
the user in such a way that the user suspends disbelief and accepts it as a real environment. On a computer, virtual
reality is primarily experienced through two of the five senses: sight and sound. The simplest form of virtual reality
is a 3-D image that can be explored interactively at a personal computer, usually by manipulating keys or the mouse
so that the content of the image moves in some direction or zooms in or out. More sophisticated efforts involve such
approaches as wrap-around display screens, actual rooms augmented with wearable computers, and haptics devices
that let you feel the display of images.
Virtual reality can be divided into:
 The simulation of a real environment for training and education.
 The development of an imagined environment for a game or interactive story.
Popular products for creating virtual reality effects on personal computers include Bryce,
Extreme 3D, Ray Dream Studio, TrueSpace, 3D Studio MAX, and Visual Reality. The
Virtual Reality Modelling Language allows the creator to specify images and the rules for
their display and interaction using textual language statements.
Computer-based virtual reality has been a common part of modern popular culture and technology for decades now.
It is used both as a tool and also for entertainment purposes. The technology has many applications, although its
importance may occasionally need some clarification.
Virtual Reality Basics
1. The basic concept of virtual reality is sensual immersion in a computer generated
environment. This may include sight, sound, touch, and smell. This is basically a kind
of controllable reality simulation.
Mr. Ganesh chand
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Sanothimi Campus, Bkt.
Network and Data Communication
Virtual Architecture
2. Architectural visualization is one of the applied uses of virtual reality today. A virtual
walk-through of a building design, prior to its construction, can actually help architects
and their clients better understand what the building will actually be like to inhabit
once built.
Pilot Training
3. The training of pilots for the aviation industry is another popular use of virtual reality
today. This is especially beneficial to airline pilots flying simulated commercial jetliners,
as it offers the ability to practice something that is relatively risky and costly with an
actual plane. Train conductors in Japan also train with virtual reality simulators.
1. Fill in the blanks.
a. MPGE stands for ..............................
b. The practice of using more than one medium at a time is called..............................
c. The............................. file format is commonly used for full motion video files.
d. ............................. uses multimedia technologies to enable students to take class
room.
e. CBT stands for..............................
f. The technologies that deliver the contents of multimedia are CD-ROM, DVD
ROM and ..............................
2. Multiple choice.
a. The additional software required to play multimedia elements on a Webpage are
called ?
i. Browser ii. Compiler iii. Plug-ins iv. Media player
b. In education, multimedia is used to produce CBTs. CBT stands for.
i. Computer Based Training ii. Computer Based Teaching
iii. Training by computer iv. All of the above
c. Find the odd one out
i. Text ii. Animation iii. Sound iv. Mail merge
d. Multimedia includes which of the following facilities.
i. Audio ii. Video iii. Audio, Video and Animation. iv. Both a. and b.
e. 3D titles in games and movies are made using this technique.
i. MS-Word ii. MS-Excel iii. Internet iv. Multimedia
3. Answer the following questions.
a. What benefits can interactive multimedia bring to education?
b. What is multimedia? Give its importance.
c. List any four application areas of multimedia.
d. What are the three key hardware components in a multimedia capable computer?
4. Write the full form of.
MPEG GIF
BMP
JPEG
VRML
AVI
CDROM
PDA
DVD
CBT
16.9 IT Policy in Nepal
Mr. Ganesh chand
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