f3226 – computer networks -1.1

8/6/2019 F3226 COMPUTER NETWORKS -1.1

1/38

BY

MOHD NAZMAN


2/38

Definition 1:` Networks A network is a set of devices (often

referred to as nodes) connected by media links.

` A node can be a computer, printer, or any other

capable of sending and /or receiving data generatedby other nodes on the network.

` The links connecting the devices are often calledcommunication channels

Definition 2:` A network is simply a group of interconnected

devices communicating with each other.


3/38

Definition :` A collection of computers, servers, mainframes, network

devices, peripherals, and/or various other devicesconnected to one another allowing for data to be sharedand used.

` A great example of a network is the Internet, connectingmillions of people all over the world together..

` Below is an example image of what a home network orsmall office network may look like.

` As can be seen below, this network is setup to enable all

computers and other devices with network abilities, such asthe Tivo, to communicate with each other as well as sharethe single Internet connection.


4/38


5/38

Advantages Network

` Sharing information- this saves on expensive diskspace and increases the availability of common dataand configurations.

` Sharing disk resources- network allows user toaccess files and application program an remote disk.

` Sharing resources- access to networked peripheralssuch printers.

`

Peer-to-peer communication` Centralized storage and backup of information.


6/38

a) Peer-to-peer network

` Also known as a P2P network, a peer-to-peer network isa network that does not have a central computer or

dedicated server;

` In other words, all computers are independent.

`

This type of network is the type of network you wouldmost likely find in home networks or small networkscomprised of a dozen or less computers.


7/38

7

Client &

Server

Client &

Server

Client &Server


8/38

8

Client &

Server

Client &

Server

Client &Server


9/38

9

No centralized data access.

Security handled by assigning each

resource a password.


10/38

10

Peer-to-peer works best with a a small

number of computers.


11/38

b) Client/Server network

` A type of network setup that utilizes both servers andclients.

` For example, a network that utilizes a DNS server is anexample of a client/server network.

` Most client/server networks are the type of networks youwould find in a corporate or business environment.


12/38

12

May I have

Worksheet-101?

Client Server


13/38

13

Sure, here

it is!

Worksheet-101Client Server


14/38

14

Server

Client

Client

Client Client

Client

Client


15/38

15

Server

Client

Client

Client Client

Client

Client


16/38

16

Centralized data access.

Centralized security.

Centralized administration, record keeping,

and control.


17/38

17


18/38

Describe the various classification of

network :

x Local Area Network (LAN)

x Wide Area Network (WAN)

x Metropolitan Area Network (MAN).


19/38

` Short forLocal-Area Network.

`A LAN is a network that has networking

equipment and/orcomputers in close proximityto each other, capable of communicating,sharing resources and sharing information.

` Most home networks and businesses who havetheir own network are on a LAN.


20/38

` Typically connects computer in a single building orcampus.

` Developed in 1970s.

` Medium : optical fibres, coaxial cables, twistedpair, wireless.

` Low latency (except in high traffic periods).

` High speed networks (0.2 to 100 Mb/sec).

` Speeds adequate for most distributed

` Systems Problems : Multi media basedapplications

` Typically buses or rings topology


21/38

` WAN

` Short forWide Area Network, WAN is a collection ofcomputers and network resources connected via anetwork over a geographic area.

` Wide-Area Networks are commonly connected eitherthrough the Internet or special arrangements made withphone companies or other service providers.

` A WAN is different from a MAN because of the distancebetween each of the networks.

` In a WAN, one network may be anywhere from severalhundred miles away, to across the globe in a differentcountry.


22/38

` Developed in 1960s.` Generally covers large distances (states, countries,

continents).` Medium : communication circuits connected by routers.` Routers forwards packets from one to another following a

route from the sender to the receiver.` Store-and-Forward Hosts are typically connected (or close

to) the routers.` Typical latencies : 100ms - 500ms.` Problems with delays if using satellites.

` Typical speed : 20 - 2000 Kbits/s. Not (yet) suitable fordistributed computing.

` New standards are changing the landscape.


23/38

` Short forMetropolitan-Area Network.

` MAN is a network that is utilized across multiplebuildings.

`A MAN is much larger than the standard Local-Area Network (LAN) but is not as large as aWide Area Network (WAN).

` Commonly is used in school campuses andlarge companies with multiple buildings.


24/38

` Generally covers towns and cities (50 kms)

` Developed in 1980s.

` Medium : optical fibres, cables.

` Data rates adequate for distributed computingapplications.

` A typical standard is DQDB (Distributed Queue

Dual Bus).

` Typical latencies : < 1 msec.` Message routing is fast.


25/38


26/38


27/38

` Client - Service requesters` Server - Service provider` Workstation - refer to a mainframe computer terminal

or a PC connected to a network`

Network interface card - hardware device that handlesan interface to a computer network and allows anetwork-capable device to access that network

` Network operating system - an Operating system (OS)designed to allow shared file and printer accessamong computers in a network, typically a local areanetwork (LAN), a private network or an Intranet


28/38

` Node - active electronic device that is attached to anetwork, and is capable of sending, receiving, or forwardinginformation over a communications channel

` Connectivity device Repeater, hub, bridge, switch, router,modem

` Backbone - part of computer network infrastructure thatinterconnects various pieces of network

` Segment - portion of a computer network wherein everydevice communicates using the same physical layer

` Topology Bus, Ring, Star, Mesh`

Transmission media Wire, Fiber Optic Cable,WirelessLink (RF or Infrared)


29/38


30/38

30

T Backbone


31/38

31

A single cable interconnects all

workstations.

The cable is terminated at both ends.


32/38

32

Star Topology


33/38

33

Star Topology

All workstations connect to a single central

hub.


34/38

34

Ring Topology


35/38

35

Ring Topology

Backbone is a ring.

Each workstation connects only to two other

workstations.


36/38

36

Mesh Topology


37/38

37

Mesh Topology

Net-1

Net-4 Net-3

Net-2


38/38

38

Internet

f3226 – computer networks -1.1

Documents