dc-lec-5 (categories of network)

8/3/2019 DC-Lec-5 (Categories of Network)

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DATA

COMMUNICATION

LECTURE-5


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Recap of Lecture 3 & 4

Physical Structure of Network

Line Configuration/ Type of Connection Topologies

Categories of Topologies


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Overview of Lecture 5

Categories of Networks LAN

MAN WAN

Interconnection of Networks: Internetworks

Internet


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Categories

of

Networks


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Categories of Networks

Today when we speak of networks, we aregenerally referring to two primary categories:

local-area networks and

wide-area networks. The category into which a network falls is determined by its

size.

A LAN normally covers an area less than 2 miles;

A WAN can be worldwide. Networks of a size in between are normally referred to as

metropolitan Area Networks and span tens of miles.


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Network

Local AreaNetworks (LANs) Wide AreaNetworks (WANs) MetropolitanArea Networks(MANs)


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Local Area Networks

A local area network (LAN) is a datacommunication system that allows a numberof independent devices to communicate

directly with each other in a limitedgeographic area.


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Local Area Networks


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ANISOLATED LAN CONNECTING 12

COMPUTERSTOAHUBINACLOSET


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Local Area Networks

Privately owned and links the devices within a smallgeographical area. LAN is basically established in a

single office,

building, campus, or a city.

Depending on the needs of an organization and the type oftechnology used, a LAN can as simple on two PCs and printer

or it can extend throughout a company and include voice,sound and video peripherals.

Currently, LAN size is limited to a few kilometers.


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Local Area Networks

Share Resources between PC or Workstation. Resources to be shared are

Hardware Printer, Scanner, CD-Rom

Software an application program or data.

LANs are distinguished from other types of

network by Geographical Area (Size) transmission media topology.


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Local Area Networks

In general, a given LAN will use only one typeof transmission medium.

The most common LAN topologies are

Bus, Star Ring.

Traditionally, LANs have data rates in the

4Mbps 16Mbps 100Mbps to 1000Mbps with gigabits systems in

development.


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13

LAN ACCESS METHODS

Broadcasting

In a broadcast LAN, transmitted information will bereceived by all stations simultaneously. The mediumaccess schemes are random access such as CSMA/CD

which may cause contention, and controlled accesssuch as token-passing, in which no contention willoccur.

Switching

In a switched architecture, a switch forward datapackets to their destinations that may be a singleuser station or another LAN segment.


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14

Ethernet Fast Ethernet,

Gigabit Ethernet

10G Ethernet

Fiber Channel

Hipper LAN

Token ring

ATM LAN

FDDI (Fiber Distributed Data Interface)

Wireless LAN

..

There are also some other technologies such as 100VG,token bus, ARCnet, but those are almost obsolete.

VARIOUS LOCALAREA NETWORKS


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MetropolitanArea Networks


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Metropolitan Area Networks

(MANs)

A MAN is designed to extend over an entire city or state.

It may be a single network such as a cable televisionnetwork, or it may be a means of connecting a numberof LANs into a large network so that resources may be

shared LAN-to-LAN as well as device-to-device. For example, a company can use a MAN to connect

the LANs in all of its offices throughout a city.

A MAN may be wholly owned and operated by a private

company, or it may be a service provided by a publiccompany such as local telephone company. A MAN islarger than LAN but smaller than WAN in size.


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Wide Area Networks

Wide Area Network.

Networking implemented on far away or longgeographical distances. For Example, networking implemented between two

continents or countries.

WAN is always based on connection between

different LANs and MANs. For Example, network between campuses of a

university in different states of a country.


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Wide Area Networks


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Wide Area Networks

WAN provides large distance transmission ofdata, voice, image and video information overlarge geographical areas that may comprise acountry, a continent or even the whole world.


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Wide Area Networks

TYPES OF WAN Enterprise WAN

A WAN that is wholly owned and is used by a single company

is known as Enterprise WAN. In other words network between two or more cities, states, or

countries for a specific person or company,

e.g. Network of Habib Bank Limited in Pakistan, and networkof NADRA throughout Pakistan.

Global WAN A WAN that is accessible throughout the world for anybody is

known as Global WAN,

e.g. Internet and PSTN all over the world.


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Wide Area Networks

A WAN can be as complex as the backbones that connect the Internet oras simple as a dial-up line that connects a home computer to the Internet.

We normally refer to the first as a switched WAN

and to the second as a point-to-point WAN.

The switched WAN connects the end systems, which usually comprise arouter (internetworking connecting device) that connects to another LANor WAN. Examples are:

X.25

Frame Relay.

Asynchronous Transfer Mode (ATM) network

wireless WAN.

Point-to-point WAN is normally a line leased from a telephone or cableTV provider that connects a home computer or a small LAN to an Internetservice provider (ISP). This type of WAN is often used to provide Internetaccess.


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WANS:

ASWITCHED WAN ANDAPOINT-TO-POINTWAN


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Internetworks When two or more networks are connected, they become an internetwork,

or internet. As an example, assume that an organization has two offices, one on the east

coast and the other on the west coast. The established office on the westcoast has a bus topology LAN; the newly opened office on the east coast hasa star topology LAN.

The president of the company lives somewhere in the middle and needs tohave control over the company from his house.

To create a backbone WAN for connecting these three entities (two LANsand the president's computer), a switched WAN (operated by a serviceprovider such as a telecom company) has been leased.

To connect the LANs to this switched WAN, however, three point-to-pointWANs are required.

These point-to-point WANs can be a high-speed DSL line offered by atelephone company or a cable modern line offered by a cable TV provider.


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A HETEROGENEOUSNETWORKMADEOFFOUR

WANSANDTWO LANS


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Internetworks


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Summary


LAN

MAN

WAN Interconnection of Networks: Internetworks

Internet


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ASSIGNMENT # 1

Brief Introduction and History of

INTERNET


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Suggested Reading

Section

1.2,

1.3,

Data Communications and Networking 4th Edition by Behrouz

A. Forouzan Sections

1.3,

Data and Computer Communication 6th Edition by William

Stallings

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