Chapter VI
Networking and Internet
1- Introduction: What is networking?
a. Networking is communicating or linking people, groups, activities or devices in order to
form networks that make it easy to exchange information or services.
b. Networking as defined in Merriam Webster dictionary is the exchange of information or
services among individuals, groups, or institutions; specifically : the cultivation of
productive relationships for employment or business.
2- Networking application
a. A list of familiar use of network and networking comprises:
i. Transportation network
ii. Telephone network
iii. Business network
iv. Travel network
v. Expert network
vi. Architects network
vii. Network of hotels
viii. Sewer network
b. Modern global business and thirsty global market made business professionals anxious
to inventing ways that improve their business practice. One efficient practice they found
consists of organizing themselves into group networks in every activity as we mentioned
in the listed network examples above.
c. Consequently, a network can be defined as interconnected number of people, objects,
businesses, services, etc…
d. This definition applies to computer networking since computers are tools used by
individuals and business decision makers to hold and process information.
e. Following this logic we can say that modern computer networking is in fact business
networking as it is hard to imagine business information networks that don’t evolve
around computers and computer information systems.
f. It is needless to mention that business networking or computer networking or any other
networking wouldn’t be this easily possible and profitable without the abundance of
advanced telecommunication media and telecommunication technology.
Computer networking
1- Computer network
a. We use to consider two or more computers linked together as a computer network but
practically a computer network consists of at least 3 computers linked together by
means of telecommunication media.
b. Computer networks are usually tailored to match the structure of a given establishment,
business or any organization.
c. Because this structure includes a lot of ramifications and substructures, business
network usually is a network of sub-networks looking like the metaphor of the tree
structure.
d. Each computer in the network is known as a node or workstation.
e. If the network has a server all other nodes are considered as clients to the server, by the
way this is the most commonly used structure in computer networking.
2- Network classification by size:
a. Local area network (LAN) covers a limited geographical area (a building or few small
buildings), the network in your computer lab is a LAN with around 30 nodes.
b. Personal area network (PAN) is a specific LAN designed to connect computer devices for
one person or household or office in very limited geographical area and ultimately
connect them to the Internet.
c. Metropolitan area network (MAN) is a larger network that may include several LANs and
PANs. This network covers larger geographical area like a whole city or a large campus
(university, college, military base, business campus).
d. Wide area network (WAN) is the largest network structure that may include several
interconnected LANs, MANs and PANs. This network covers large areas like a state, a
country or several countries or even a continent.
e. The largest area network is the Internet because it is the collection of all networks
connected together by the Internet backbone.
3- Network classification by physical structure (physical topology):
a. Star network:
client1
client2
server
client3
client4
i. Consists of several computer nodes connected to a central hub.
ii. The central server offer services to the other nodes that are considered as client
nodes.
iii. Most used structure in business computer networking.
b. Bus network:
Bus (backbone)
Node1
Node2
Node4
Node3
i. Consists of a backbone cable extended all along the network area.
ii. Several computers connected in parallel to the same backbone which is called a
bus because of this type of connection.
iii. No server in a bus network. Nodes share files and other information.
iv. Easy to connect and monitor network.
c. Ring network:
n1
n5
n2
n4
n3
i. Consists of a specific bus network that has both ends linked together.
ii. Used in locations where the computers are physically located very close to a
ring
iii. Message always flows clockwise and priorities are also established in the order
clockwise.
iv. No server involved. Nodes connect and share files as they configure them
depending on who needs what?
d. Mesh networking topology:
n1
n5
n4
n2
n3
i. Consists of several computers where each node is connected with all other
nodes.
ii. Expensive structure if we need to lay a huge quantity of cables or implement
other media for this purpose.
iii. No server is usually needed. Exchange of files and information as previously
configured by nodes (who needs what?).
iv. Access authorization for sharing files should be strictly controlled
v. Rarely used without Internet backbone connection
e. Peer-to-peer (P2P) network:
i. Special mesh structure that uses the Internet backbone as a communication
medium with each node in the network.
ii. Very flexible structure as it may connect unlimited number of nodes that may
include every computer that has Internet connection.
iii. Eliminates the need of a server by using the file sharing technology that allows
every node to share files with all other nodes.
f. Tree network:
i. Consists of a combination of a bus network with several star networks
ii. This network fits a department that comprises several divisions where each
division has a star network and all stars are connected via a bus.
iii. Priorities and message flow control are more complicated in this network
structure.
4- Network protocol (network logical topology)
a. Network protocol is a set of rules designed to control all network functions by assuming
the following responsibilities:
i. Establishing network priorities and enforcing them.
ii. Maintaining strict communication discipline in the network.
iii. Controlling network access and network security.
iv. Establishing communications with network nodes from internal nodes and
external messages applying the handshaking technology
b. Handshaking technology consists of the following steps achieved by the network
protocol:
i. Protocol detects a message originated by node A or coming from outside source
addressed to node B
ii. Protocol intercepts the message and inspects its validity and security status and
make sure it doesn’t collide with other network messages.
iii. Protocol warns node B about the message by checking if it is available and
willing to receive it.
iv. To complete the handshaking process, protocol connects the sender with the
receiver allowing the message to flow from origin to destination.
v. If node B is busy with other messaging business the handshaking process will be
postponed as long as necessary.
c. Ethernet protocol: Was commercially released in 1980 and it is until today the most
popular protocol among LAN users
i. Ethernet technology is known as CSMA/CD which stands for (Carrier Sense
Multiple Access/Collision Detection.
ii. This technology is based on the principle of polite conversation between a
group of civilized people with the following scenario:
1. Many people start talking at the same time.
2. They stop talking because each one of them will leave the turn to
others.
3. When an absolute silence is achieved, some guys will restart talking and
again if more than one is talking they will stop.
4. The process will continue until only one is talking and all others listening
iii. Ethernet protocol assumes the enforcement of the courtesy role by stopping all
messages if more than one station is trying to send.
iv. Ethernet sends the message to all nodes but none can receive it except the
addressees.
d. Token ring protocol:
i. This protocol is designed for the ring network
ii. A signal called token that may be a code is sent to the station that has the
sending priority
iii. When that station finishes it passes the token to the station that has the next
priority and so forth
iv. In a ring network priorities are clockwise in the order and the message flows
clockwise exactly.
e. Some networks use the Internet protocol which we will see along with many other
protocols of Internet services ahead.
5- Wireless networking:
a. WLAN network connects nodes via radio-waves instead of cables. It is known as Wi-Fi
network and the latest wireless technology is the Wi-Max network.
b. Wi-Fi network stands for (Wireless-Fidelity) and is known by its IEEE code 802.11 where
we must distinguish from 802.11a, 802.11b, 802.11g, and 802.11n
i. 802.11 was released in 1997 uses a 2.4 GHz and bandwidth 20 MHz can be used
over a distance of 20 meter indoor and 100 meter outdoor
ii. 802.11a released on the eve of the 3rd millennium SEPT-OCT 1999 uses a 3.7
GHz frequency and 20 MHz bandwidth that improved the range to 35 meters
indoor and 120 meters outdoor.
iii. 802.11b uses 2.4 GHz and same bandwidth of 20 MHz with the improvement of
the outdoor working distance to 140 meters.
iv. 802.11g similar to the 802.11b and data rate between 6 and 54 (Mbit/s) and
was released in June 2003.
v.
802.11n released in OCT 2009 used a 2.4/5 GHz frequency and bit stream
between 7.2 Mbit/s and 72.2 Mbit/s the working range was improved to 70
meters indoor and 250 meters outdoor.
vi. Other scheduled releases for 2013 (802.11ad) and 2014 (802.11ac) that will
introduce new improvements to the WLAN technology.
c. Wi-MAX (Worldwide interoperability for Microwave Access).
i. Wireless broadband Internet access designed to replace the DSL as more
convenient mobile and fixed Internet access.
ii. Wi-MAX influence on Internet access may be compared tp cellphone impact on
the telephone networking and telephone industry.
iii. The IEEE 802.16 and 802.16e standard enable to use 2.3 GHz, 3.3 GHz, 2.5 GHz
and 3.5 GHz.
iv. Wi-MAX range may reach 50 Kilometers about 31 miles (enough to cover a big
city or a county).
v. Designed to provide 30-40 Mbit/s that was updated in 2011 to 1 Gbit/s for fixed
stations.
vi. However Wi-MAX has the limitation of not being able to deliver the maximum
speed at the maximum range (speed in bit/s is inversely proportional to the
distance from the base station).
vii. Wi-MAX 802.16 started the 4th generation (4G) of smart phones and mobile
Internet access that evolved as follow:
1. LTE (Long Term Evolution) is defined as a 4G standard was effectively
first launched in 2009 in Scandinavia (Oslo and Stockholm).
2. Wi-MAX 1, 1.5 and 2 were all designed as wireless MAN (Metropolitan
area Network).
3. Wi-MAX 2nd release core technology (802.16m) provides data speed 4
times faster than the first release 802.16 and 802.16e.
4. 802.16m release 2 is backward compatible with Wi-MAX release 1 so
the migration from Wi-MAX 1 to Wi-MAX 2 needs only to update the
software or upgrade the channel cards.
5. By the start of 2012 Wi-MAX networks around the world were
estimated to have more than one billion subscribers.
d. Blue tooth networking: (Blootooth.com)
i. Bluetooth networking technology was developed in 1994 in the labs of
ERICSSON (the Scandinavian communication giant company) by 2 employees
Jaap Haartsen and Sven Mattisson
ii. It was called by this name after the Scandinavian king Harald (935 – 985) who
was very productive in building bridges and making all Scandinavian tribes
communicate with each other. This king was nicknamed “BLUETOOTH” because
his front teeth were blue colored affected by his love of eating berries.
iii. Bluetooth is a full wireless networking technology using low power transmitters
that are designed to link computing devices in PAN (Personal Area Network)
over short distances (10 meters = 33 feet or less).
iv. Newer Bluetooth technology using more powerful transmitters can be used for
up to 100 meters or 330 feet.
v. The frequency band used is 2402-2480 MHz divided into 79 channels one MHz
apart assigned by the ISM (Industrial Scientific Medical) agency.
vi. In 1998 Bluetooth SIG (Bluetooth Special Interest Group) was established by
Ericsson, Nokia, IBM, Toshiba and INTEL this group is monitoring the use of
protocol stack and Bluetooth qualification requirements for electronic devices
and equipment.
vii. In 2002 Bluetooth enabled devices were around 250 million. Today it is
estimated that more than a billion devices are using the technology.
viii. Computers who are not equipped with Bluetooth adaptor can be Bluetooth
connected thru wireless adapter.
ix. One Bluetooth adapter can connect several Bluetooth devices.
e. Characteristics of Bluetooth network:
i. The basic network in a Bluetooth system is the “Pico-net” where the number of
nodes cannot exceed 8 devices because the address is 3 digits (2^3 = 8).
ii. Each device in Pico-net is a peer device (it can act a master or a slave so at a
given time we have one master and 7 slaves.
iii. Two or more Pico-nets form a scatter-net and the name is meaningful in this
networking technology because a scatter happens when one slave of any Piconet elects to behave as master or slave in another one.
iv. This interconnectivity is very important because it enables Bluetooth devices to
reach far beyond the short range limitation of Bluetooth networking.
f. Bluetooth protocol: because of the diversity of Bluetooth devices the technology has a
stack of several protocols to handle diverse services and provide for implementation
flexibility. These protocols are:
i. LMP (Link Management protocol) establishes and manages links and ability to
query.
ii. BNEP (Bluetooth Network Encapsulation Protocol) used by Bluetooth PNA to
manage packet switching and transmission in the network.
iii. HCI (Host Controller Interface) establishes and controls communication
between operating system of computer devices and Bluetooth IC (Integrated
Circuit).
iv. SDP (Service Discovery Protocol) enables any Bluetooth device to discover
services offered by other devices and their characteristics and parameters.
v. TCS and TCS-BIN (Telephony Control Protocol allows voice and data calls
between devices of Bluetooth network.
vi. WAP (Wireless Application Protocol) provides necessary access to telephone
and computer networks for mobile users who are connecting thru Bluetooth
network.
g. Samples of Bluetooth apps: Here are some applications:
i. PROFINET: Bridge that connects two Ethernet networks.
ii. Wii of Nintendo and PS3 of Sony game consoles use Bluetooth to accommodate
their game controllers.
iii. Personal security application: Bluetooth tag (marker) attached to protected
objects and has constant communication with a phone. If the communication is
interrupted a warning signal is activated.
iv. RTLS (Real Time Location System) app that enables user to track and locate
objects by attaching or embedding Bluetooth markers or tags and using readers
to intercept and process signals sent by the tags. Bluetooth OBEX (Object
Exchange) is an application that allows exchange of information and transfer of
files within all devices of Bluetooth network.
The Internet
1- Internetworking:
a. The basic idea behind Internet invention is connecting networks with each other
creating a network of networks (MAN or WAN).
b. This process is known as internetworking and several technological steps were already
set up that guided to the Internet.
c. Networks may have different topologies and different protocols and to connect them
we need to set up a conversion or translation service between them.
2- Connecting networks:
a. Two similar networks (same protocol) are connected by means of a bridge whose job is
to connect 2 or more segments and control packet flow between them.
b. Two dissimilar networks (have different protocols) are connected by means of gateway
device which provide assistance to make sure the message flows uniformly in both
networks
c. Network switch links segments of the network to bridges or gateways. Basic switches
don’t process data.
d. A switch that does process data is called multilevel switch because it will be working at a
level 3 processing.
3- Packet switching/circuit switching:
a. Internetworking technology will be impossible with circuit switching technology that
reserves a circuit for each message until it is done.
b. This technology allows fewer messages to use the network pathways simultaneously.
c. Packet switching, on the other hand, optimizes the use of network pathways by dividing
each message into parcels of data called packets whose trip takes short time.
d. Packets are sent from A to B using most available pathways between them instead of
only one like in circuit switching. Consider the following scenario of 9 packets going from
A to B.
i. Packet1 takes itinerary I1
ii. Packet2 takes Itinerary I2 and so on…
iii. Packet9 takes Itinerary I9
iv. Upon arrival to B, a guide will gather them regroup them and deliver them
altogether one message as they initially were.
4- An internetwork is basically a small Internet the biggest internetwork of all networks and
internetworks is the Internet that controls our daily life (as individual, community, society,
business, government and so on…)
5- Evolution of the Internet:
a. Because Internet changed the way we live and the way we do business, it is very
important that you know how this miraculous technology evolved and be literate about
its too many services and how to put them in action for improving our life and our
business while contributing to serving our nation and the global society.
b. DOD (Department of Defense) started the Internet development journey in February
1958 (right after the Soviet union successfully launched Sputnik orbiter in 1957):
i. A committee of scientists called ARPA (Advanced Research Project Agency) also
named DARPA (Defense Advanced Research Project Agency).
ii. DARPA’s mission was to create a network that enables scientists to network
without interruption even in case of nuclear warfare.
iii. DARPA hired high tech companies mainly BBN (Bolt Beranek Neuman) as
contractors to work on the project.
iv. MERIT (Michigan Educational Research Information Triad) is packet switching
network that was created in 1966 by many universities in Michigan for research
collaboration
v. ARPANET (Advanced Research Project Agency Network) was started by DARPA
in December 1969 connecting 4 university nodes:
1- UCLA (Network Measurement Center (NMC))
2- Stanford (Stanford Research Institute (SRI))
3- University of Utah
4- University of California-Santa Barbara
vi. 1971-1972: Computer engineer Ray Tomlinson invented the E-mail while
working for BBN and implemented it on ARPANET which was developed by BBN.
1- Email was the first and most important service using the Internet
backbone and attracted the attention of political and economy leaders
about the importance of that tool in the global business.
2- 1981 the number of host computers reached 213 and growing by
20/year approximately this number grews several folds after the
34567-
addition of other services and especially the WWW service to the
Internet.
1981 IBM released the first PC and Time magazine choses the computer
as “Man of the year” 1981.
1984 Apple released its MAC with the user friendly GUI (Graphical User
Interface). All that gave huge push to the Internet drive.
1985 NSFNET (National Science Foundation Network) was created based
on MERIT network and evolved into the modern Internet in 1995.
1990, the year when ARPANET shuts down, 300000 hosts were
connected to the Internet using PCs, MACs.
Other large computers used as servers for networks connected to the
Internet whose number grow from 3000 in 1986 to more than 30000 in
1987 and continue growing with the advance of computer hardware
and software technology and networking protocol software technology.
6- Internet protocol
a. Since its implementation in 1969 till its shut down in 1990 ARPANET used a variant of
packet switching protocol known as IMP (Interface Message Processor).
b. The message is cut into parcels of data called PDUs (Protocol Data Unit) where the
packet or PDU cannot exceed 1008 bits
c. IMP protocol slowness (acknowledge receipt of each packet) wasn’t able to face the
large number of networks and hosts that exceeds today the billion and was about
500000 even before the invention of the WWW (World Wide Web) as predominant
service provided by the Internet.
d. Internet protocol TCP/IP (Transmission Control Protocol/Internet Protocol) was the right
solution where each part fulfills a specific job making the process very fast to handle the
huge number of exchanged packets:
i. TCP (Transmission Control Protocol) is the part that takes care of the packet at
the origin and destination making sure they are well prepared at the origin and
assemble them prior to the correct delivery at the destination.
ii. TCP cuts the message into packets below 1500 bytes each because Ethernet
protocol in LANs cannot take more than 1500 bytes.
iii. IP (Internet Protocol) is the part that takes care of addressing the packets and
directs them thru their proper itineraries.
7- Internet backbone:
a. Internet backbone can be compared to human backbone or spine because it connects
Internet host user to other users like human backbone connect to every organ and cell
of the human body.
i. This backbone comprises all fast and broad band networks and connections all
around the world including:
ii. Under ocean cables installed by submarines and known as submarine cables
that link most continents.
iii. Satellites owned and operated by large telecommunications companies because
the private sector took over in 1994.
iv. Ground high speed telecommunication and networking infrastructure including
wired and wireless infrastructure.
a. Most important cables of internet and internetwork backbone are T1 and T3
lines that we have seen in the previous telecommunications chapter.
i. T 1 line:
1. Reserved circuit that uses copper or fiber optic cables to
operate over various networking distances.
2. T1 data rate is 1.54 Mbps similar to symmetric DSL
3. Monthly Cost is about $1000 and more and mostly used by
hotels, apartment buildings and subdivision and some
business and college campuses where the cost can be
justified.
ii. T3 line:
1. Use copper and fiber optic cables to operate as a reserved
circuit equivalent to an aggregation of 28 T1 lines.
2. Data rate is about 44.7 Mbps.
3. Monthly cost is about $3000 - $12000 or more that’s why it
is used as a backbone of large business network or the
headquarters of big businesses and large size campuses and
military bases.
b. Routers
Different Internet pathways are connected together thru the use of huge
number of routers that are responsible of:
i. Monitoring and easing Internet traffic
ii. Monitoring packets itineraries and direct them to thei correct
destination
iii. Apply Internet protocol to all services that use the Internet.
8- Internet operation
a. Nobody own the Internet, however big telecommunication companies own parts of the
Internet backbone and make profit by charging use fees so Internet providers can be
divided into 3 tiers:
i. Tier 1: comprises huge ISP (Internet Service Provider) companies that don’t
need to pay anything to access all nodes of the Internet. Qwest, AT&T, Verizon,
sprint, French telecom, Finn telecom etc…
ii. Tier 2: comprises ISP companies that need to pay for some access from Tier 1
companies.
iii. Tier 3: Comprises ISP companies that lease Internet access from Tier 1 or Tier 2
companies provide services to subscribers and don’t own connections by
themselves.
iv. Tier 1, Tier 2 and Tier 3 companies are all Internet service providers (ISP)s and
that’s why the quality of Internet service is normally better with Tier 1
companies then Tier 2 then Tier 3.
b. Internet Access: Five most important characteristics of Internet access are:
i. Reliability: Connection is available when needed without unexpected
interruption due to coverage and weather
ii. Speed: Download speed and upload speed in Mbps.
iii. Cost should be reasonable and justified.
iv. Customer satisfaction oriented help and assistance service
v. Free array of popular general information
1- News
2- Weather
3- Gaming
4- Travel and entertainment.
vi. ISP (Internet Service Provider) supplies a modem (modulator demodulator) that
is able to accommodate all services provided.
9- Internet access methods
a. Dial-up connection: The first used method of access
i. Host must dial a number and wait until getting access.
ii. Very slow access impossible to deal with multimedia because it can only handle
up to 56 Kbps
iii. Uses telephone line so you cannot use the telephone and access the Internet
simultaneously (one service at a time)
iv. Service is ON only after you dial and be lucky to get connected
v. Still used in some rural areas where there is no fast Internet yet.
vi. The least expensive service of all.
b. DSL (Digital Subscriber Line)
i. Always On Internet service
ii. Provided by telephone companies and uses telephone lines.
iii. Because of switching technology provided by the ISP, you can use both the
telephone and the Internet simultaneously.
iv. Fast Internet that may go up to 6 Mbps.
v. Price is reasonable but much higher than dial-up connection service
c. Cable TV: provides the connection as part of a package that includes TV channels and
possible more services like Internet telephone
i. Always ON connection
ii. A splitter modem is provided by the CTV provider that routes TV channels to the
TV and Internet service to the computer or the wireless router if you want to
install a WI-FI network.
iii. You can watch TV and access Internet and its services simultaneously.
iv. Very fast connection up to 8 Mbps and may reach up to 50 Mbps in case
businesses want speed beyond what is offered for the public.
v. Slightly higher cost than DSL
vi. Very reliable (not affected by weather condition.
d. Satellite access: direct satellite access is provided by many companies that operate and
manage satellites like HughesNet, MyBlueDish and Wild blue in the USA.
i. Provides fast Internet in rural areas where only dial-up connection or no
connection at all is available.
ii. Always ON connection
iii. Speed may go up to 18 Mbps.
iv. Very reliable Internet access
v. Most expensive Internet service.
10- Important Business special networks we need to cover in this chapter include:
a. VPN (Virtual Private Network):
i. Very important business network that uses client server topology and has no
physical installed structure.
ii. May have partly installed local structure.
iii. Operates using public networks (mainly the Internet) to exchange private data
and make private communications
iv. To enforce and enhance communication security a protocol known as
“Tunneling” protocol is used.
v. Tunneling protocol usually does the following:
1- Authenticate the client requesting communication to the VPN
2- Create a secured tunnel (pathway).
3- Complete and control the communication thru that tunnel.
vi. VPN is used by businesses to create connection possibilities for their Intranet
and Extranet as we will see below.
b. Intranet:
i. Internetwork of many private networks in a company designed to accommodate
teamwork and enhance communication and file sharing in a company
ii. Uses the Internet protocol TCP/IP
iii. Hi security network in a business.
iv. Only authorized executives, managers and employees can access it (no outsiders
allowed in)
v. An Intranet consists of:
1- Internal e-mail system
2- Database loaded with important information and news about the
company and its working environment.
3- Websites and some other services as needed.
4- Secured and firewalled Internet access
5- VPN connection to support remote access for company’s staff.
c. Extranet:
i. Internetwork like Intranet but with strictly controlled outside access
ii. Uses VPN (Virtual Private Network) to connect with another network in a
different organization.
iii. Extranets are widely used by medium and large companies because of the
simplicity and convenience they add to business – customer relationship and
easiness of communication between businesses.
d. VAN (Value Added Network):
i. considered as a competitor to the post office for business documents and file
exchange between businesses.
ii. Privately owned highly secured network using private communication media
iii. Provides specific services known as VAN services like legal service or translation
or accessing special database.
iv. Handles electronic mail and file transfer between businesses like EDI (Electronic
Data Interchange) transactions.
v. Businesses lease lines to connect to the network and need to install specific
software for this purpose.
vi. Internet replaced many VANs lately and successfully introduced itself as much
efficient and economic tool to replace the VAN.
vii. VAN use remains popular between businesses that are seeking high security
level when exchanging files