Network Transmission Technology

Based on the transmission technology computer networks are classified into two.

1. Broadcast Networks

2. Point-to-Point networks 

Broadcast Networks

Broadcast network have a communication channel that is share by all the nodes in the network. BUS network is an example of broadcast network.

     BUS network

 All the nodes on the network receive the messages sent by any machine in broadcast network. An address field of the message determines the intended recipient. Upon receiving a message, the node checks the address field of the message. If the message is intend to itself then process the packet otherwise it simply ignore the packet.

Broadcasting refers to a method of transferring a message to all recipients simultaneously. Some broadcast system also support multicasting. Multicasting means send data to a subset of nodes in the network.

Broadcasting

 Multicasting

                                       

Point-to-point Networks

In the case of point-to-point network, there exist many connections between individual pairs of nodes. A transmitted packet may visit some intermediate node before they actually reach its destination. There may multiple routes between two nodes so routing algorithms play an important rule in point to point networks.       

The connection between two nodes either one of the following

1. Dedicated

2. Shared

In the case of dedicated connection, there exist a dedicated connection between sender and receiver. Three types of dedicated connections are there

a.     simplex

b.    half duplex

c.     duplex

Simplex connections only allow the transmission of data in one direction. Radio and TV are examples. In contrast, links that can be used in either direction, but only one way at a time, like a single-track railroad line are called half-duplex links. CBZ radio is a half-duplex device. Links that can be use in both directions at the same time, like a two-lane road, are call full-duplex links. Point-to-point transmission with one sender and one receiver is sometimes call unicasting.

Shared devices share the transmission link by using the technique known as multiplexing, we will discuss multiplexing later. 

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