# Computer Networks Routing Algorithms

ROUTING ALGORITHMS

Routing Algorithm:- The Algorithm that manages the Routing Tables and makes the Routing Decisions is called Routing Algorithm.

Implementation of Connection – Oriented Network layer Service:-

• In this service the subnet is called Virtual Circuit Subnet.
• A path from Source Router to Destination Router is established before sending any packets. That Router is used for all traffic flowing over that connection.

Ex:- A Telephone System.

• When connection is released, the virtual circuit is also terminated.

Let us see an example, The figure shows the routing using Virtual Circuit subnet, In this Host H1 wants to send packets to H2

Now H1 will establishes a connection1 with Host H2 whenever packet comes from host H1 , we use connection 1 with identifier as 1. i.e, from routing table of A , a packet is coming from H1 , identifier is 1 then use the outgoing router C with identifier 1 .

Similarly for H3 use identifier as 2. This is called as lablel Switching .

The comparison between these connection oriented and connection less services or Virttual circuit or data gram subnets is given in the table.

## Author: Lakshmi Prasanna Ponnala

Completed M.Tech in Digital Electronics and Communication Systems.

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