08-17-2017, 12:39 AM
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NETWORK SWITCHING
Submitted By Adarsh Arya
Roll No. 4315
Methods of Switching
Circuit Switching
Message switching
Packet Switching
Circuit Switching
Seeking out and establish a physical path end-to-end.
Circuit switching implies the need to first set up a dedicated end-to-end path for the connection before information transfer take place.
Once the connection is made the only delay is propagation time.
Message Switching
A store-and-forward network where the block of transfer is a complete message.
Since messages can be quite large, this can cause:
buffering problems
high mean delay
Store-and-Forward Networks
Each block is received in its entirety, inspected for errors, and retransmitted along the path to the destination. This implies buffering at the router and one transmission time per hop.
Packet Switching
A store-and-forward network where the block of transfer is a complete packet. A packet is a variable length block of data with a tight upper bound.
Packet Switched Networks
Connection-oriented Protocols
A setup stage is used to determine the end-to-end path before a connection is established.
Connectionless Protocols
No set up is needed.
Each packet contains information which allows the packet to be individually routed hop-by-hop through the network.
Datagram vs Virtual Circuit
Datagram
Each datagram packet may be individually routed.
Virtual Circuit
Virtual circuit set up is required.
All packets in a virtual circuit follow the same path.