Switching
The technique of transferring the information from one computer network to another computer network is known as switching.
Switching Mode
- Store and Forward
- Cut Through
- Fragment-Free
Switching Techniques
- Circuit Switching (Time Division, Space Divison)
- Message Switching
- Packet Switching (Datagram, Virtual Circuit Approach)
1. Circuit Switching
- A dedicated path between sender and reciever is established.
- Used in public telephone network.
- It has 3 phases: circuit establishment, data transfer, circuit disconnnect
2. Message Switching
- No dedicated path is established between sender and receiver.
- Message is traferred as a complete unit and routed through intermediate nodes at which it is stored and forwarded.
- Each and every node stores the entire message and then forward it to the next node.
3. Packet Switching
- Messages are splitted into packets.
- Each packet contains some information in it's header such as source address, destination address, sequence number etc
- These packets will travel accross the network taking the shortest path as possible.
- All packets are resembled at the receiving end in correct order.
- There are 2 approach for packet switching: datagram and virtual circuit approach.
- In datagram approach, nodes takes the routing decision to forward packets.
- In virtual circuit approach, nodes doesn't take routing descision. A pre-planned route is established.