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ASSIGNMENT NO. 01

LAN AND WAN CONNECTIVITY

Submitted By:

SUKANNYA CHETRY (BA/08/EC/002)

ANKITA RAJ (BA/08/EC/003)

KRITHIKA SUNDARESAN (BA/08/EC/004)

SANGEETA BURAGOHAIN (BA/08/EC/005)

POWLOMI ROY (BA/08/EC/010)

SARBARI CHAKRABORTY (BA/08/EC/012)

RIMA KAUSHIK (BA/08/EC/015)

COURSE NAME: FUNDAMENTALS OF TELECOMMUNICATION

ENGINEERING

COURSE CODE: EC-2101

SUBMISSION DATE: 28-10-2009

SESSION: JULY-DECEMBER, 2009.

NORTH EASTERN REGIONAL INSTITUTE OF SCIENCE AND TECHNOLOGY

(DEEMED UNIVERSITY)

Under the Ministry of Human Resource Development, Govt. of India

Itanagar, Arunachal Pradesh, India, Nirjuli-791109

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CONTENTS:

1. Computer networking

1.1 Categories

2. LAN-Local Area Network

2.1 Examples

2.2 History

2.3 Features

2.4 Technology

2.5 Networking equipment

2.6 Cabling

3. WAN-Wide Area Network

3.1 Examples of WAN

3.2 Features

3.3 WAN technology

3.4 Components of WAN

3.5 Networking equipment

4. LAN versus WAN

5. Recent trends

5.1 LAN

5.2 WAN

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1. Computer networking:

Computer networking is the engineering discipline concerned with communication

between computer systems or devices. Computer networking is sometimes considered a

sub-discipline of telecommunications, computer science, information technology and

computer engineering.

A computer network is any set of computers or devices connected to each other with the

ability to exchange data. All devices are interconnected to allow communication with a

variety of different kinds of media, including twisted pair copper wire cable, coaxial

cable, optical fiber, power lines and various wireless technologies. The devices can be

separated by a few meters (e.g. via Bluetooth) or nearly unlimited distances (e.g. via the

interconnections of the internet).

1.1 Categories:

Networks can be categorized in several different ways viz. by scale, by network design,

network protocols, etc. One way to categorize the different types of computer networks is

by their scope or scale. For historical reasons, the networking industry refers to nearly

every type of design as some kind of area network. Common examples of area network

types are:

LAN - Local Area Network

WLAN - Wireless Local Area Network

WAN - Wide Area Network

MAN - Metropolitan Area Network

SAN - Storage Area Network, System Area Network, Server Area Network,

or sometimes Small Area Network

CAN - Campus Area Network, Controller Area Network, or sometimes

Cluster Area Network

PAN - Personal Area Network

DAN - Desk Area Network

LAN and WAN were the original categories of area networks, while the others have

gradually emerged over many years of technology evolution.

2. LAN - Local Area Network:

A computer network established within a building or a campus or a small geographical

area is called local area network or LAN. In other words, “a LAN is a group of

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computers and associated devices that share a common communication line or a wireless

link” (i.e. microwave link or satellite link).

Fig 1: LAN connectivity

2.1 Examples of LAN:

1. A LAN may be established on a University campus or between office blocks in an

office park.

2. A big corporate perhaps like Anglo American, could generally have a LAN that

might span several buildings.

2.2 History:

As larger universities and research labs obtained more computers during the late 1960s,

there was increasing pressure to provide high-speed interconnections. A report in 1970

from the Lawrence Radiation Laboratory detailing the growth of their "Octopus" network

gives a good indication of the situation.

Cambridge Ring was developed at Cambridge University in 1974 but was never

developed into a successful commercial product.

Ethernet was developed at Xerox PARC in 1973–1975, and filed as U.S. Patent

4,063,220. In 1976, after the system was deployed at PARC, Metcalfe and Boggs

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published their seminal paper, "Ethernet: D:WAN technology distributed Packet-

Switching For Local Computer Networks."

ARCNET was developed by Datapoint Corporation in 1976 and announced in 1977. It

had the first commercial installation in December 1977 at Chase Manhattan Bank in New

York.

2.3 Features:

LANs operate in a limited space, usually up to 1 km range.

The smallest home LAN can have exactly two computers; a large LAN can

accommodate many thousands of computers.

LANs are typically owned, controlled, and managed by a single person or

organization.

A LAN is useful for sharing resources other applications. A LAN in turn often

connects to other LANs, and to the Internet or other WAN.

Individual users can share data or files on a LAN as if the data or files resided

on their respective computers; a central computer used for this purpose is

called a server. Laser printers and other peripheral equipment can be

connected to a LAN for common use.

Coaxial and fiber-optic cables are popular communication lines for LANs

because they provide fast data transmission and are easy to install.

Many LANs are divided into logical groups called subnets. An Internet

Protocol (IP) "Class A" LAN can in theory accommodate more than 16

million devices organized into subnets.

2.4 Technology: Main LAN technologies:

Ethernet: It is the most popular LAN technology today.

Token ring: The data is transmitted in tokens.

FDDI: Fiber Distributed Data Interface is a fiber optic token ring LAN.

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ARCNET: Attached resources Computer Network was first LAN based

networking system.

Switched Ethernet is the most common Data Link Layer implementation on local area

networks. At the Network Layer, the Internet Protocol has become the standard.

However, many different options have been used in the history of LAN development and

some continue to be popular in niche applications. Smaller LANs generally consist of one

or more switches linked to each other—often at least one is connected to a router, cable

modem, or ADSL modem for Internet access.

Larger LANs are characterized by their use of redundant links with switches using the

spanning tree protocol to prevent loops, their ability to manage differing traffic types via

quality of service (QoS), and to segregate traffic with VLANs. Larger LANS also contain

a wide variety of network devices such as switches, firewalls, routers, load balancers,

sensors.

LANs may have connections with other LANs via leased lines, leased services, or by

tunneling across the Internet using virtual private network technologies.

ARCNET, Token Ring and many other technologies have been used in the past, and G.hn

may be used in the future, but Ethernet over twisted pair cabling, and Wi-Fi are the two

most common technologies currently in use.

2.5 Networking equipment:

Most local area networks are built with relatively inexpensive hardware such as Ethernet

cables, network adapters, and hubs. Wireless LAN and other more advanced LAN

hardware options also exist.

Specialized operating system software may be used to configure a local area network. For

example, most flavors of Microsoft Windows provide a software package called Internet

Connection Sharing (ICS) that supports controlled access to LAN resources.

2.6 Cabling:

Early LAN cabling had always been based on various grades of co-axial cable, but IBM's

Token Ring used shielded twisted pair cabling of their own design, and in 1984 StarLAN

showed the potential of simple Cat3 unshielded twisted pair—the same simple cable used

for telephone systems. This led to the development of 10Base-T (and its successors) and

structured cabling which is still the basis of most LANs today. In addition, fiber-optic

cabling is increasingly used.

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3. WAN - Wide Area Network:

A WAN or wide area network is a geographically-dispersed collection of LAN’s. As the

term implies, a WAN spans a large physical distance. Thus a WAN may be defined as “a

data communication network that spans large geographic area, such as a state, province

or country”.

Fig 2: WAN connection over the earth

Fig 3: Interconnectivity of LAN and WAN

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3.1 Examples of WAN:

Internet: It is a worldwide public WAN.

ARPANET: It is a WAN network established by Advance Research Project

Agency of U.S.A. for its own use, connecting about 40 universities and research

institutions throughout U.S.A. and Europe.

INDONET: It is a WAN established by CMC( Computer Maintenance

Corporation) India to link 3 IBM/4361 systems each at Mumbai, Kolkata and

Chennai and a DPD 11/44 system at New Delhi.

3.2 Features:

WANs often connect multiple smaller networks, such as local area networks

(LANs) or metro area networks (MANs).

The medium used for WANs are telephone lines, microwave links and satellite

links.

Transmission rate usually range from 1200 bps to 6 Mbps, although some

connections such as ATM and Leased lines can reach speeds greater than 156

Mbps.

The cost to transmit data in WAN may be high because the transmission media

are eased or paid lines or links.

A WAN may not be owned by a single organization but it operated under

collective ownership and management.

WANs tend to use technology like ATM, Frame Relay and X.25 for connectivity

over the longer distances.

3.3 WAN technology:

WANs are often built using leased lines. At each end of the leased line, a router connects

to the LAN on one side and a hub within the WAN on the other. Leased lines can be very

expensive. Instead of using leased lines, WANs can also be built using less costly circuit

switching or packet switching methods.

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Network protocols deliver transport and addressing functions. Protocols are “pre-defined

rules, procedures and agreements for the exchange of data/information through WAN”.

Protocols including Packet over SONET/SDH, MPLS, ATM and Frame relay are often

used by service providers to deliver the links that are used in WANs. X.25 was an

important early WAN protocol, and is often considered to \ be the "grandfather" of

Frame Relay as many of the underlying protocols and functions of X.25 are still in use

today (with upgrades) by Frame Relay. The protocol applicable presently is known as

TCP/IP (Transmission Control Protocol/ Internet Protocol).

The world's most popular WAN is the Internet. Some segments of the Internet, like VPN-

based extranets, are also WANs in themselves. Finally, many WANs are corporate or

research networks that utilize leased lines.

3.4 Components of WAN:

1. Access routers: These are the gateway devices connected to the local area

networks (LAN) . The access router connects to a switch or hub on the local

network and serves as a gateway to the WAN. The access routers establish LAN-

to-LAN connections and forward network traffic between users at the remote

sites.

2. WAN connections: These are the actual connectivity between sites. Common

WAN links are public networks like the Internet, private networks such as lines

leased from service providers, and the public phone system.

The speed of a WAN connection depends on its capacity and characteristics.

Analog and ISDN (Integrated Services Digital Network) links are common and

inexpensive, but lack the performance of faster technologies and require a dial-up

connection between sites. In other words, the link is temporary and must be re-

established every time information is sent. DSL (digital subscriber line) and cable

modem links are much faster and always on; these links are permanent and don’t

require one modem to dial into another.

3. Security strategies: These prevent any unauthorized people from accessing

communications between sites, particularly when they travel over public networks

like the Internet.

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3.5 Networking equipments:

WANs generally utilize different and much more expensive networking equipment than

do LANs. Key technologies often found in WANs include SONET, Frame Relay, and

ATM.

4. LAN versus WAN:

Whereas a LAN (local area network) is a network that links computers, printers

and other devices located in an office, a building or even a campus , a WAN

(wide area network) is a system that extends for greater distances and is used to

connect LANs (local area networks) together.

A LAN is generally referred to a network contained within a building or an office

or a campus. A WAN is a network that connects campuses.

To set up a LAN -relatively speaking- is cheap. WAN's are expensive.

WAN is generally slower than LAN. The data transmission speed in LAN may be

up to 10 Mbps, whereas in WAN it is generally about 1/10th of that in LAN.

5. Recent trends:

5.1 LAN:

An Ethernet is the most popular LAN technology in use today, which provides a

data transmission speed of up to 10 Mbps.

For high transmission speed of data, Fast Ethernet IEEE has been established,

which raises the data transfer speed to 100 Mbps with minor changes in cable

structure.

Gigabit internet connections with a speed of 1000 Mbps are also available. The

most common protocols in use today are TCP/IP, IPX, DECnet, Apple Talk etc.

5.2 WAN:

WANs are moving towards higher bandwidth which can only be delivered by

technology at speeds high enough to satisfy the need for bandwidth.

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Wi-Fi is the technology for connecting clients remotely and is the fastest growing

technology offered by all the major players in this market. Wi-Fi or 802.11g is

wireless connectivity offering to connect between 11 and 56Mbps and even

higher. The advantage of wireless technology is it’s lack of the need of physical

wire/copper or Fiber to connect to the client.

Another means of connecting is Asynchronous Transfer Mode (ATM) and this

certainly offers the fastest Wide Area Connection available today. Speeds start at

155Mbps and running to approx 622Mbps, although with recent technology, we

can expect speeds to be significantly higher.