Computer Networks

What is network?

•A collection of devices that can communicate together•The network achieves this by providing a set protocols

Understanding the pieces of a network

HUBs and SWITCHes

Application that use the network

Classification of Networks

1. Geographic spread of nodes and hosts ( Scale )

•LAN

•MAN

•WAN

A. Local Area Network (LAN)

B. Metropolitan area network (MAN)

C. Wide area network (WAN)

2. Access restrictions

• Public Networks

• Private networks

Public networks, accessible to the average user, but may require registration. Like Internet.

Private networks are for the private use of the organizations to which they belong. Like banks, hospitals, etc.

3. Communication model employed by the nodes

•Point-to-point

•Broadcasto unicast transmission network

o broadcast transmission network

o multicast transmission network

Point-to-point

Unicast transmission

Broadcast transmission

Multicast transmission

4. Switching model employed by the nodes

•circuit switching

•packet switching

circuit switching and packet switchingIn circuit switching, a dedicated

communication path is allocated between A and B.

In packet switching, data is divided into packets which are sent from A to B.

Network Topologies•Bus

•Ring

•Star

•Extended star

•Hierarchical

•Mesh

Bus Topologyconnects all the devices using a single cable.

Star and Extended-Star Topologies

The star topology is made up of a central connection point where all the cabling segments meet

Ring TopologyHosts are connected in the form of a ring or

circle.The computers act as signal boosters or

repeaters.

Hierarchical TopologyIt uses a trunk node from which it branches

to other nodes.

Full-Mesh and Partial-Mesh TopologiesThe full-mesh topology connects all devices

to each other for redundancy.In a partial-mesh topology, at least one

device maintains multiple connections to others.

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