Introduction to Network
• A network is a set of devices (nodes) connected by communication links. A node can be a
computer, printer, or any other device capable of sending and/or receiving data generated by other
nodes on the network
• Data communications are the exchange of data between two devices via some form of transmission
media such as a wire cable or wireless.
1.
Delivery → Correct destination
2.
Accuracy → Accurate data
3.
Timelines → Real-time transmission
4.
Jitter
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→
Uneven delay
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Types of connections

Point to point
 A dedicated link is provided
between two devices

Multipoint
 More than two specific
devices share a single link
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Impact of networks on daily lives
What is the impact of the internet on students?
Studies conducted on the students show that internet addiction has been accompanied by major problems such as
the educational drop, reduced the curriculum study, anxiety, reduced interpersonal relationships, reduced
physical activities, irregularity, and nutritional diseases
The basic requirements of a reliable network :
Networks are comprised of four basic elements: hardware, software, protocols, and the connection medium. All
data networks are comprised of these elements, and cannot function without them.
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Employment opportunities in the networking field
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Common Network Attacks
There are two main types of network attacks:
1. passive and 2. Active.
In passive network attacks, malicious parties gain unauthorized access to networks, monitor, and steal
private data without making any alterations.
Active network attacks involve modifying, encrypting, or damaging data
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Ref:https://blog.totalprosource.com/6-common-types-of-cyber-attacks
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latest trends in Networking
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Network Communication
• Network communication, or internetworking, defines a set of protocols (that is, rules and
standards) that allow application programs to talk with each other without regard to the hardware
and operating systems where they are run.
Different Types of Communication Networks
1.
Local Area Network(LAN)
2.
Metropolitan Area Network(MAN)
3.
Wide Area Network(WAN)
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Ref: http://aboutnetworking.weebly.com/types-of-computer-networks-advantages-and-disadvantages-ofnetworks.html
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Transmission Medium
The transmission medium can be defined as a pathway that can transmit information from a
sender to a receiver. Transmission media are located below the physical layer and are controlled by
the physical layer. Transmission media are also called communication channels.
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System Types
• Peer–Peer Network or Peer-based
• Client Server Based Network
A client-server network is a medium through
which clients access resources and services from
a central computer, via either a local area
network (LAN) or a wide-area network (WAN),
such as the Internet.
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Continue…
Cluster Server:
Cloud Server:
A cloud server is a pooled, centralized server
resource that is hosted and delivered over a
network
A cluster is a group of inter-connected
computers or hosts that work together to
support applications and middleware (e.g.
databases).
A cloud is a type of a server, which is remote
(usually in Data Centers), meaning you access it
via the internet
In a cluster, each computer is referred to as a
“node”. Unlike grid computers, where each node
performs a different task, computer clusters
assign the same task to each node.
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Centralized network architecture is built
around a single server that handles all the
major processing. Less powerful workstations
connect to the server and submit their requests to
the central server rather than performing them
directly. This can include applications, data
storage, and utilities
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Network Virtualization (NV) refers to abstracting
network resources that were traditionally delivered in
hardware to software.
NV can combine multiple physical networks to one
virtual, software-based network, or it can divide one
physical network into separate, independent virtual
networks
.
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1-5 LAYERED TASKS

A network model is a layered architecture





Protocol:


1.14
Task is broken into subtasks
Implemented separately in layers in the stack
Functions need in both systems
Peer layers communicate
A set of rules that governs data communication
It represents an agreement between the communicating devices
Tasks involved in sending a letter
Topics discussed in this section:
Sender, Receiver, and Carrier
Hierarchy (services)
1.15
1-5.1 THE OSI MODEL
Established in 1947, the International Standards Organization (ISO)
is a multinational body dedicated to worldwide agreement on
international standards.
An ISO is the Open Systems Interconnection (OSI) model is the
standard that covers all aspects of network communications from
ISO. It was first introduced in the late 1970s.
1.16
ISO is the organization.
OSI is the model.
Topics discussed in this section:
Layered Architecture
Peer-to-Peer Processes
Encapsulation
1.17
Layered Architecture
Layers
Seven layers of the OSI model
Layer 7. Application
Layer 6. Presentation
Layer 3. Network
Layer 2. Data Link
Layer 1. Physical
1.18
Receiver
Layer 4. Transport
Sender
Layer 5. Session
Layered Architecture






1.19
A layered model
Each layer performs a subset of the required
communication functions
Each layer relies on the next lower layer to perform
more primitive functions
Each layer provides services to the next higher layer
Changes in one layer should not require changes in
other layers
The processes on each machine at a given layer are
called peer-to-peer process
PEER – TO – PEER PROCESS
1.20

Communication must move downward through the layers on
the sending device, over the communication channel, and
upward to the receiving device

Each layer in the sending device adds its own information to
the message it receives from the layer just above it and passes
the whole package to the layer just below it

At the receiving device, the message is unwrapped layer by
layer, with each process receiving and removing the data
meant for it
PEER – TO – PEER PROCESS


1.21
The passing of the data and network information down through
the layers of the sending device and backup through the layers
of the receiving device is made possible by interface between
each pair of adjacent layers
Interface defines what information and services a layer must
provide for the layer above it.
The interaction between layers in the OSI model
1.22
An exchange using the OSI model
1.23
LAYERS IN THE OSI MODEL
Topics discussed in this section:
1. Physical Layer
2. Data Link Layer
3. Network Layer
4. Transport Layer
5. Session Layer
6. Presentation Layer
7. Application Layer
1.24
Physical Layer
The physical layer is responsible for the movements of
individual bits from one hop (node) to the next.

Function







1.25
Physical characteristics of interfaces and media
Representation of bits
Data rate
Synchronization of bits
Line configuration (point-to-point or multipoint)
Physical topology (mesh, star, ring or bus)
Transmission mode ( simplex, half-duplex or duplex)
Physical layer
1.26
Data Link Layer
The data link layer is responsible for moving
frames from one hop (node) to the next.

Function





1.27
Framing
Physical addressing
Flow control
Error control
Access control
Data link layer
1.28
Hop-to-hop delivery
1.29
Example 1
In the following Figure, a node with physical address 10 sends a frame to a
node with physical address 87. The two nodes are connected by a link. At the
data link level, this frame contains physical addresses in the header. These
are the only addresses needed. The rest of the header contains other
information needed at this level. The trailer usually contains extra bits
needed for error detection
1.30
Network Layer
The
network
layer
is
responsible
delivery of individual packets from
the source host to the destination host.



1.31
for
Source-to-destination delivery
Responsible for the delivery of packets from the original
source to the final destination
Functions
 Logical addressing
 routing
the
Network layer
1.32
Source-to-destination delivery
1.33
Example 2
We want to send data from a node
with network address A and
physical address 10, located on
one LAN, to a node with a
network address P and physical
address 95, located on another
LAN. Because the two devices are
located on different networks, we
cannot use physical addresses
only; the physical addresses only
have local influence. What we
need here are universal addresses
that can pass through the LAN
boundaries. The network (logical)
addresses have this characteristic.
1.34
Transport Layer
The transport layer is responsible for the delivery
of a message from one process to another.
1.35

Process-to- process delivery

Functions

Port addressing

Segmentation and reassembly

Connection control ( Connection-oriented or connection-less)

Flow control

Error control
Transport layer
Segmentation and reassembly
1.36
Reliable process-to-process delivery of a message
1.37
Example 3
Data coming from the
upper layers have port
addresses j and k (j is the
address of the sending
process, and k is the
address of the receiving
process). Since the data size
is larger than the network
layer can handle, the data
are split into two packets,
each packet retaining the
port addresses (j and k).
Then in the network layer,
network addresses (A and
P) are added to each
packet.
1.38
Session Layer
The session layer is responsible for dialog
control and synchronization.
 It establishes, maintains and synchronize the
interaction between communicating system
 Function
1.39

Dialog control

Synchronization (checkpoints)
Session layer
Synchronization
1.40
Presentation Layer
The presentation layer is responsible for translation,
compression, and encryption.
 Concerned with the syntax and semantics of the
information exchanged between two system
 Functions
 Translation ( EBCDIC-coded text file  ASCII-coded file)
 Encryption and Decryption
 Compression
1.41
Presentation layer
1.42
Application Layer
The application layer is responsible for
providing services to the user.

1.43
Functions
 Network virtual terminal (Remote log-in)
 File transfer and access
 Mail services
 Directory services (Distributed Database)
 Accessing the World Wide Web
Application layer
1.44
Summary of layers
1.45
Summary of layers
OSI Model
Sender
User
support
layers
User
Network
Network
support
layers
Data
Function
7. Application
Network process to application
6. Presentation
Data representation and encryption
5. Session
Inter-host communication
Segment 4. Transport
End-to-end connections and reliability
Packet 3. Network
Path determination and logical
addressing
Frame 2. Data Link
Physical addressing
Bit
1.46
Layer
1. Physical
Media, signal and binary transmission
Receiver
Data
unit
Network Models
Lecture 3
TCP/IP Model
1.47
1-5.2 TCP/IP PROTOCOL SUITE
The layers in the TCP/IP protocol suite do not exactly match those
in the OSI model. The original TCP/IP protocol suite was defined
as having four layers: host-to-network, internet, transport, and
application. However, when TCP/IP is compared to OSI, we can
say that the TCP/IP protocol suite is made of five layers: physical,
data link, network, transport, and application.
Topics discussed in this section:
Physical and Data Link Layers
Network Layer
Transport Layer
Application Layer
1.48
1.49
TCP/IP Model
OSI Model
TCP/IP and OSI model
Internet Layer
TCP/IP supports the Internet Protocol IP ( unreliable).
IP is a host-to-host protocol.
Supporting protocols:
• Address Resolution Protocol (ARP)
• Reverse Address Resolution Protocol (RARP)
• Internet Control Massage Protocol (ICMP)
• Internet Group Massage Protocol (IGMP)
1.50
Transport Layer
Process-to-process protocol.
• User Datagram Protocol (UDP)
• Transmission Control Protocol (TCP)
•
1.51
Stream Control Transmission Protocol (SCTP)
Network Standards
A networking standard is a document that has been developed to provide technical requirements,
specifications, and guidelines that must be employed consistently to ensure devices, equipment, and
software that govern networking are fit for their intended purpose.
• Network Standards
• Application layer − HTTP, HTML, POP, H.323, IMAP.
• Transport layer − TCP, SPX.
• Network layer −IP, IPX.
• Data link layer − Ethernet IEEE 802.3, X.25, Frame Relay.
• Physical layer −RS-232C (cable), V.92 (modem)
P1- Ref:https://desklib.com/document/benefits-and-constraints-of-different-ne/
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Physical Topology
Tree
1.53
MESH Topology
• Every device has a dedicated point-to-point
link to every other device
• Dedicated
• Link carries traffic only between the two
devices it connects
• A fully connected mesh network has n(n-1)/2
physical channels to link n devices
• Every device on the network must have n-1
input/output (I/O) ports
• Advantage
• Less traffic, robust, secure, easy to maintain
• Disadvantage
• Need more resources (cable and ports),
expensive
n(n-1)/2 physical duplex links
1.54
STAR Topology
• Each device has a dedicated point-to-point link only to a central controller,
usually called a hub.
• No direct traffic and link between devices
• Advantages
• Less expensive
• Easy to install and reconfigure
• Robustness
• Disadvantage
• Single point of failure
1.55
BUS Topology
• A multipoint topology
• All devices are linked through a backbone cable
• Nodes are connected to the bus cable by drop lines and taps.
• Drop line
• A connection running between the device and the main cable
• Tap
• A connector that either splices into the main cable or punctures the sheathing of
a cable to create a contact with the metallic core
• Advantage:
• Ease of installation
 Disadvantages:
• Difficult reconnection and fault isolation
• Broken or fault of the bus cable stops all transmission
1.56
RING Topology
• Each device is dedicated point-to-point connection only with the two devices on either side of it
• A signal is passed along the ring in the direction, from device to device, until it reaches its
destination
• Each device in the ring incorporates a repeater
• Advantages
• Relatively easy to install and reconfigure
• Fault isolation is simplified
• Disadvantage
• Unidirectional traffic
1.57
Tree Topology
Tree topologies integrate multiple topologies together
Example: Tree topology
integrates multiple star
topologies together onto a
bus
• Advantages:
• Point-to-point wiring for individual segments.
• Supported by several hardware and software venders.
• Disadvantages:
• Overall length of each segment is limited by the type of cabling used.
• If the backbone line breaks, the entire segment goes down.
• More difficult to configure and wire than other topologies.
1.58
A hybrid topology: a star backbone with three bus networks
1.59
IEEE 802.3 Ethernet
Network Architecture - Protocols
• Physical: Actual signal transmission
• Data-Link: Framing / Error Detection
• Network: Routing / Addressing
• Transport: Congestion / Flow Control
• Application: Specific to user needs
Layered Protocols – (HTTP)
Data Link Layer - Ethernet
• Invented in 1973 @ Xerox.
(IEEE 802.3)
• Originally a LAN technology – extended to MAN / WAN.
• Same frame format, different wiring schemes, data rates across generations.
• Most common version (10BaseT) – 1990.
Ethernet Generations
• Original Ethernet:
• Coaxial cable (10Base5)
• Thicknet.
• Next Generation:
• Thin coax cable (10Base2)
• Thinnet.
• Modern Ethernet:
• Twisted pair ethernet
(10BaseT)
• Uses hub: physical star but
logical bus.
Ethernet Components
• NIC – Network Interface Card
• Integrated Tx/Rx – direct interface to medium.
• MAU – Media Attachment Unit
• Attaches network interface to the medium (integrated into NIC).
• AUI – Attachment Unit Interface
• Decouple physical layer -reuse MAC design with different media.
• MII – Media Independent Interface
• Like AUI for gigabit / faster ethernets.
Ethernet Addressing
• 48-bit address
• Address assigned when NIC card is manufactured.
• Packets can be sent to
• Single address – Unicast
• All stations on network – Broadcast (address = all 1s.)
• Subset of stations – Multicast
• Broadcast (address = all 1s.)
• All receivers accepts unicast / broadcats.
• Half addresses reserved for multicast (247)
• NIC can accepts zero or more multicasts.
Ethernet Frame
Sender adds:
• Senders address is source
• Recepients addreess in destination
• Type of data in frame type
• Error check data (CRC)
Receiver NIC:
• Gets transmitted frame.
• Examines address and either accepts or rejects.
• Passes frame to system software.
Media Access Control - MAC
• Shared medium – stations take turns at sharing the medium.
• Media access control ensures fairness.
CSMA / CD
• Carrier Sense: wait till medium is idle before sending frame.
• Multiple Access: multiple computers use the same shared media.
Each uses same access algorithm.
• Collision Detection: Listen to medium – detect if another station’s
signal interferes – back off and try again later.
CSMA / CD
• If collision occurs: wait a random time t1 - 0< t1<d.
• D depends on transmission speed – time for frame width or 512 bits.
• If second collision occurs, wait a random time t2 - 0< t2<2d.
• Double range for each succesive collision.
• Exponential backoff
• No acknowledgement like TCP.
• CSMA/CA used in wireless networks where not all stations receive message.
• Both sides send small message followed by data:
• X is about to send to Y
• Y is about to receive from X
• Data frame sent from X to Y.
Recent Developments
• 100Base-FX
• LED light source / MMF / 2 km max distance.
• Modal dispersion – limited bandwidth
• 100Base-SX (IEEE 802.3z)
• Short wavelength laser (850 nm)
• Max distance = 5 km.
• 100Base-LX
• Long wavelength laser (1310 nm)
• Max distance = 5 km.
Beyond Gigabit Ethernet
• 10 Gb/s Ethernet
• No CSMS/CD, same frame format.
• Applications
• Upgrade LANs / Backbone.
• MAN applications.
IEEE 802.5 (Token Ring) LAN
IEEE 802.5 (Token Ring): Ring Topology
• Shared ring medium: all nodes see all frames
• Round Robin MAC Protocol: determines which station can transmit
• A special 3-byte pattern, the token, circulates around the ring perpetually and
represents the "right to transmit"
• This establishes round-robin media access
• Data flow is unidirectional
• All data flows in a particular direction
around the ring; nodes receive frames
from their upstream neighbor and forward
them to their downstream neighbor
• Data rate: 4 or 16 Mbps
R
R
R
R
IEEE 802.5 (Token Ring) Operation
• The token bit sequence circulates around the ring.
• Each station forwards the token if it does not have a frame to transmit.
• A station with data to send seizes the token (repeater now in transmit state) and begins
sending it’s frame. It can transmit for length of time called the Token Hold Time (THT)
= 10 mseconds.
• Each station forwards the frame.
• The destination station notices its address and saves a copy of the frame as it also
forwards the frame.
• When the sender sees its frame return, it drains it from the ring and reinserts a token.
When the last bit of the returning frame has been drained, the repeater switches
immediately to the listen state.
IEEE 802.5 (Token Ring) using a Hub
• The star-wired ring topology uses the physical layout of a star in conjunction
with the token-passing data transmission method. Data are sent around the
star in a circular pattern. This hybrid topology benefits from the fault
tolerance of the star topology and the reliability of token passing.
IEEE 802.5 (Token Ring): Bypass relays and
Wire Center
• Bypass relays protect ring topology from node failure at the hardware level.
IEEE 802.5 (Token Ring) Frame Format
TOKEN:
•
•
•
•
•
•
Start
Delimiter
Access
Control
End
Delimiter
Start delimiter (1 byte): serves the same basic purpose as the preamble in an Ethernet frame.
Access Control (1 byte): contains the token bit, monitor bit, and priority bits
Frame Control (1 byte): contains access control information
Destination Address (6 bytes)
Source Address (6 bytes)
Data (no size limit specified): this is the actual data being sent (IP packet). Since the THT = 10 mseconds, practical
size limit of the frame is 4500 bytes.
• Frame Check Sequence (4 bytes): CRC error checking bits
• End Delimiter (1 byte): signifies the end of the frame
• Frame Status Field (1 byte): serves as the ACK and indicates whether the address was recognized and the frame
copied, which is done by the receiving computer before being sent back around the ring
IEEE 802.5 (Token Ring): Ring
Maintenance
• There is a special station on the ring called a monitor station. It is responsible to identify and address
situations dealing with a lost token and an orphan frame.
• Lost Token:
• Monitor station knows the number of stations on the ring and so calculates maxTHT = n * THT
(n is the number of stations on the ring). It keeps a timer of how long since it last saw the token
pass by. If this is more than maxTRT, it drains the ring and inserts a new token in the ring.
• Orphan frame:
• A frame can get orphaned if the sending station goes down before it can drain it’s frame. As a
frame passes by the monitor, it sets the "monitor" bit in the header of the frame. If it sees a
frame with this bit already set, it knows it is an orphan frame. Then the monitor drains the ring
and inserts a new token in the ring.
IEEE 802.5 (Token Ring) Performance
• Under light load conditions where few stations have data to send, token ring
performance is fair but there is an overhead of passing the token.
• Under heavy load condition where most of the stations have data to send,
performance is excellent and utilization approaches 100%. The token is fully utilized
in this case.
IEEE 802.3 (Ethernet) vs IEEE 802.5 (Token Ring)
• Ethernet is widely used at present (> 90% market share). People are experienced in
using this technology.
• Ethernet uses CSMA/CD as the MAC protocol while Token Ring uses Round Robin
protocol.
• Token Ring uses point-to-point connections between ring interfaces so that the
electronic hardware can be fully digital and simple. There is no need for collision
detection. The Ethernet NIC card requires some analog circuitry to be able to detect
collisions.
• Token Ring has excellent throughput at high loads since there is no possibility of
collisions unlike 802.3.
• Under light load, Token Ring experiences token passing overhead. Ethernet has no
such overhead and has excellent performance at light loads.
IEEE 802.5 (Token Ring) Token Frame Format
IEEE 802.5 (Token Ring)Frame Format Details
• The access control byte contains the priority and reservation fields, as well as a token
bit (used to differentiate a token from a data/command frame) and a monitor bit (used
by the active monitor to determine whether a frame is circling the ring endlessly).
• The frame control byte indicates whether the frame contains data or control
information. In control frames, this byte specifies the type of control information.
• The frame status byte is only present in Token Ring frames. It contains the A and C
bits.When a frame arrives at the interface of a station with the destination address, the
interface sets the A bit (=1), as it passes through. If the interface copies the frame to the
station, it also sets the C bit (=1). A station might fail to copy a frame due to lack of
buffer space or other reasons.
• When the station which sent the frame strips it from the ring, it examines the A and C
bits.The three possible combinations are;
1. A=0 and C=0; Destination not present or powered up.
2. A=1 and C=0; Destination present but frame not accepted.
3. A=1 and C=1; Destination present and frame copied.
• This arrangement provides an automatic acknowledgment of the delivery status of each
frame.
IEEE 802.5 (Token Ring) Hierarchical Setup
P2- Ref:https://www.ukessays.com/essays/information-systems/explain-the-impact-of-network-topology-communication-and-bandwidthrequirements.php
Purpose of Protocol
• A network protocol is a set of established rules that dictate how to format, transmit
and receive data so that computer network devices -- from servers and routers to
endpoints -- can communicate, regardless of the differences in their underlying
infrastructures, designs or standards.
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IP ADDRESSING
• An identifier for a computer or device on a TCP/IP network. Networks using the TCP/IP
protocol route messages based on the IP address of the destination. The format of an IP
address is a 32-bit numeric address written as four numbers separated by periods. Each
number can be zero to 255. For example, 1.160.10.240 could be an IP address.
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IP Subnetting
87
The Catch
Before subnetting:
• In any network (or subnet) one can use most of the IP addresses for host
addresses.
• One loses two addresses for every network or subnet.
1. Network Address - One address is reserved to that of the network.
2. Broadcast Address – One address is reserved to address all hosts in that
network or subnet.
Subnet Example
Network address 172.19.0.0 with /16 network mask
Network Network
172
19
Host
Host
0
0
Subnet Example
Network address 172.19.0.0 with /16 network mask
Network Network
Host
Host
172
19
0
0
Using Subnets: subnet mask 255.255.255.0 or /24
Network Network
Subnet
Host
Network Mask:
255.255.0.0 or /16
11111111
11111111
00000000
00000000
Subnet Mask:
255.255.255.0 or /24
11111111
11111111
11111111
00000000
•
•
Applying a mask which is larger than the default subnet mask, will divide your
network into subnets.
Subnet mask used here is 255.255.255.0 or /24
Subnet Example
Network address 172.19.0.0 with /16 network mask
Using Subnets: subnet mask 255.255.255.0 or /24
Network Network
172
172
172
172
172
172
172
19
19
19
19
19
19
19
Subnet
Host
0
1
2
3
etc.
254
Host
Host
Host
Host
Host
Host
255
Host
Subnets
255
Subnets
28 - 1
Cannot use last
subnet as it
contains broadcast
address
Subnet Example
Network address 172.19.0.0 with /16 network mask
Using Subnets: subnet mask 255.255.255.0 or /24
Network Network
172
172
172
172
172
172
172
19
19
19
19
19
19
19
Subnet
Host
0
1
2
3
etc.
254
0
0
0
0
0
0
255
0
Subnets
Addresses
255
Subnets
28 - 1
Cannot use last
subnet as it
contains broadcast
address
Subnet Example
Class B address 172.19.0.0 with /16 network mask
Using Subnets: subnet mask 255.255.255.0 or /24
Network Network
172
172
172
172
172
172
172
19
19
19
19
19
19
19
Hosts
Addresses
Subnet
Hosts
0
1
2
3
etc.
254
1
1
1
1
1
1
254
254
254
254
254
254
Host
Each subnet has
254 hosts, 28 – 2
255
Subnet Example
Network address 172.19.0.0 with /16 network mask
Using Subnets: subnet mask 255.255.255.0 or /24
Network Network
172
172
172
172
172
172
172
19
19
19
19
19
19
19
Subnet
Host
0
1
2
3
etc.
254
255
255
255
255
255
255
255
255
Broadcast
Addresses
255
Subnets
28 - 1
Cannot use last
subnet as it
contains broadcast
address
Subnet Example
Network address 172.19.0.0 with /16 network mask
Using Subnets: subnet mask 255.255.255.0 or /24
172.19.0.0/24
172.19.5.0/24
172.19.10.0/24
172.19.25.0/24
Important things to remember about Subnetting
• You can only subnet the host portion, you do not have control of the network portion.
• Subnetting does not give you more hosts, it only allows you to divide your larger network into
smaller networks.
• When subnetting, you will actually lose host adresses:
• For each subnet you lose the address of that subnet
• For each subnet you lose the broadcast address of that subnet
• You “may” lose the first and last subnets
• Why would you want to subnet?
• Divide larger network into smaller networks
• Limit layer 2 and layer 3 broadcasts to their subnet.
• Better management of traffic.
Subnetting
–
Example
• Host IP Address: 138.101.114.250
• Network Mask: 255.255.0.0 (or /16)
• Subnet Mask: 255.255.255.192 (or /26)
Given the following Host IP Address, Network Mask and Subnet mask find the following
information:
• Major Network Information
• Major Network Address
• Major Network Broadcast Address
• Range of Hosts if not subnetted
• Subnet Information
• Subnet Address
• Range of Host Addresses (first host and last host)
• Broadcast Address
• Other Subnet Information
• Total number of subnets
• Number of hosts per subnet
Major Network Information
• Host IP Address: 138.101.114.250
• Network Mask: 255.255.0.0
• Subnet Mask: 255.255.255.192
• Major Network Address: 138.101.0.0
• Major Network Broadcast Address: 138.101.255.255
• Range of Hosts if not Subnetted: 138.101.0.1 to 138.101.255.254
Step 1: Convert to Binary
128 64 32 16 8 4 2 1
IP Address
Mask
138.
10001010
11111111
255.
101.
01100101
11111111
255.
114.
01110010
11111111
255.
Step 1:
Translate Host IP Address and Subnet Mask into binary notation
250
11111010
11000000
192
Step 2: Find the Subnet Address
IP Address
Mask
Network
138.
10001010
11111111
10001010
138
101.
01100101
11111111
01100101
101
114.
01110010
11111111
01110010
114
250
11111010
11000000
11000000
192
Step 2:
Determine the Network (or Subnet) where this Host address lives:
1. Draw a line under the mask
2. Perform a bit-wise AND operation on the IP Address and the Subnet Mask
Note: 1 AND 1 results in a 1, 0 AND anything results in a 0
3. Express the result in Dotted Decimal Notation
4. The result is the Subnet Address of this Subnet or “Wire” which is
138.101.114.192
Step 2: Find the Subnet Address
IP Address
Mask
Network
138.
10001010
11111111
10001010
138
101.
01100101
11111111
01100101
101
114.
01110010
11111111
01110010
114
250
11111010
11000000
11000000
192
Step 2:
Determine the Network (or Subnet) where this Host address lives:
Quick method:
1.
Find the last (right-most) 1 bit in the subnet mask.
2.
Copy all of the bits in the IP address to the Network Address
3.
Add 0’s for the rest of the bits in the Network Address
Step 3: Subnet Range / Host Range
G.D.
IP Address
Mask
Network
10001010
11111111
10001010
01100101
11111111
01100101
S.D.
01110010
11 111010
11111111
11 000000
01110010
11 000000
 subnet
  host 
counting range
counting
range
Step 3:
Determine which bits in the address contain Network (subnet) information and
which contain Host information:
• Use the Network Mask: 255.255.0.0 and divide (Great Divide) the from the
rest of the address.
• Use Subnet Mask: 255.255.255.192 and divide (Small Divide) the subnet from
the hosts between the last “1” and the first “0” in the subnet mask.
Step 4: First Host / Last Host
G.D.
S.D.
IP Address
Mask
Network
10001010
11111111
10001010
01100101
11111111
01100101
01110010
11 111010
11111111
11 000000
01110010
11 000000
 subnet
  host 
counting range
counting
range
First Host
10001010
138
01100101
101
01110010
114
11
000001
193
Last Host
10001010
138
01100101
101
01110010
114
11
111110
254
Broadcast
10001010
138
01100101
101
01110010
114
11
111111
255
Host Portion
• Subnet Address: all 0’s
• First Host: all 0’s and a 1 in rightmost bit
• Last Host: all 1’s and a 0 in rightmost bit
• Broadcast: all 1’s
Step 5: Total Number of Subnets
G.D.
01100101
11111111
01100101
01110010
11 111010
11111111
11 000000
01110010
11 000000
 subnet
  host 
counting range
counting
range
01100101
101
01110010
114
11
000001
193
01100101
101
01110010
114
11
111110
254
10001010
01100101
01110010
Subtract one “if”138all-zeros subnet
101 cannot be used
114
11
111111
255
IP Address
Mask
Network
10001010
11111111
10001010
S.D.
Host
• Total First
number
of10001010
subnets
138
• Number of subnet bits 10
10001010
Host
• 210Last
= 1,024
138
• 1,024 total subnets
Broadcast
•
• Subtract one “if” all-ones subnet cannot be used
Step 6: Total Number of Hosts per Subnet
G.D.
IP Address
Mask
Network
10001010
11111111
10001010
01100101
11111111
01100101
Host
• Total First
number
of10001010
hosts per 01100101
subnet
S.D.
01110010
11 111010
11111111
11 000000
01110010
11 000000
 subnet
  host 
counting range
counting
range
11
101
01110010
114
000001
193
01100101
101
01110010
114
11
111110
254
10001010
01100101
Subtract one for138
the subnet address
101
01110010
114
11
111111
255
138
• Number of host bits 6
10001010
Host
• 26Last
= 64
138
• 64 host per subnets
Broadcast
•
• Subtract one for the broadcast address
• 62 hosts per subnet
• ICMP
ICMP (Internet Control Message Protocol) is a network protocol used for
diagnostics and network management. A good example is the “ping” utility which
uses an ICMP request and ICMP reply message. When a certain host of port is
unreachable, ICMP might send an error message to the source.
• FTP
File transfer protocol is a way to download, upload, and transfer files from one
location to another on the internet and between computer systems.
FTP enables the transfer of files back and forth between computers or through the
cloud. Users require an internet connection in order to execute FTP transfers.
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• HTTP
Stands for "Hypertext Transfer Protocol." HTTP is the protocol used to transfer data over the web. It is part of the
Internet protocol suite and defines commands and services used for transmitting webpage data. HTTP uses a serverclient model. A client, for example, may be a home computer, laptop, or mobile device.
Basically, HTTP is a TCP/IP based communication protocol, that is used to deliver data (HTML files, image files,
query results, etc.) on the World Wide Web. The default port is TCP 80, but other ports can be used as well. It provides
a standardized way for computers to communicate with each other.
• SMTP
SMTP is used to send emails, so it only works for outgoing emails. To be able to send emails, you need to provide the
correct SMTP server when you set up your email client. Unlike POP3 and IMAP, SMTP can't be used to retrieve and
store emails. SMTP is also responsible for setting up communication between servers.
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• POP3
Post Office Protocol 3, or POP3, is the most commonly used protocol for
receiving email over the internet. This standard protocol, which most email
servers and their clients support, is used to receive emails from a remote server and
send to a local client.
• SSL
SSL ensures the data that is transferred between a client and a server remains
private. This protocol enables the client to authenticate the identity of the server.
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Wireless Networks
• A wireless network refers to a computer network that makes use of Radio
Frequency (RF) connections between nodes in the network.
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• SECOND GENERATION (2G)
• 2G refers to the second generation of mobile networks based on GSM. The radio signals used by the 1G
network were analog, while 2G networks were digital. 2G capabilities were achieved by allowing multiple
users on a single channel via multiplexing. During 2G, cellular phones were used for data along with voice.
Some of the key features of 2G were:
• Data speeds of up to 64 kbps
• Use of digital signals instead of analog
• Enabled services such as SMS and MMS (Multimedia Message)
• Provided better quality voice calls
• It used a bandwidth of 30 to 200 KHz
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• THIRD GENERATION (3G)
• The 3G standard utilises Universal Mobile Telecommunications System (UMTS) as its core network
architecture. 3G network combines aspects of the 2G network with new technologies and protocols to deliver
a significantly faster data rate. By using packet switching, the original technology was improved to allow
speeds up to 14 Mbps. It used Wide Band Wireless Network that increased clarity. It operates at a range of
2100 MHz and has a bandwidth of 15-20 MHz. Some of the main features of 3G are:
• Speed of up to 2 Mbps
• Increased bandwidth and data transfer rates
• Send/receive large email messages
• Large capacities and broadband capabilities
• International Mobile Telecommunications-2000 (IMT-2000) were the specifications by the International
Telecommunication Union for the 3G network; theoretically, 21.6 Mbps is the max speed of HSPA+.
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FOURTH GENERATION (4G)
• The main difference between 3G and 4G is the data rate. There is also a huge difference between 3G and 4G
technology. The key technologies that have made 4G possible are MIMO (Multiple Input Multiple Output) and
OFDM (Orthogonal Frequency Division Multiplexing). The most important 4G standards are WiMAX and LTE.
While 4G LTE is a major improvement over 3G speeds, it is technically not 4G. What is the difference between 4G
and LTE?
• Even after it was widely available, many networks were not up to the required speed of 4G. 4G LTE is a “fourth
generation long term evolution”, capable of delivering a very fast and secure internet connection. Basically, 4G is
the predetermined standard for mobile network connections. 4G LTE is the term given to the path which has to be
followed to achieve those predefined standards. Some of the features of 4G LTE are:
• Support interactive multimedia, voice, video.
• High speed, high capacity and low cost per bit (Speeds of up to 20 Mbps or more.)
• Global and scalable mobile networks.
• Ad hoc and multi-hop networks.
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