Different types of Routing in Network Layer

there are four type of routing methods are there those are:

         1 Fixed
  2 Flooding
  3 Random
  4 Adaptive

       1 Fixed Routing:

1 Single permanent route for each source to destination pair

2 Determine routes using a least cost algorithm 

3 Route fixed, at least until a change in network topology

2) Flooding:

1 No network info required Packet sent by node to every neighbor

2 Incoming packets re transmitted on every link except incoming link

3 Eventually a number of copies will arrive at destination

4 Each packet is uniquely numbered so duplicates can be discarded

5 Nodes can remember packets already forwarded to keep network load in bounds

6 Can include a hop count in packets

3 Random:

1 Node selects one outgoing path for re transmission of incoming packet

2 Selection can be random or round robin

3 Can select outgoing path based on probability calculation

4 No network info needed

5 Route is typically not least cost nor minimum hop

 4 Adaptive:

1 Used by almost all packet switching networks

2 Routing decisions change as conditions on the network change

1Failure

2 Congestion

3 Requires info about network

4 Decisions more complex

5 Tradeoff between quality of network info and overhead

6 Reacting too quickly can cause oscillation

7 Too slowly to be relevant