Sunday, November 30, 2008

What is C and R in OSPF debugs?

Nov 29 15:02:46.765: OSPF: Mismatched hello parameters from 10.1.1.2
Nov 29 15:02:46.765: OSPF: Dead R 40 C 40, Hello R 10 C 10, Mask R 255.255.255.252 C 255.255.255.0
Have you ever seen such type of debug messages with R and C values? Yesterday I was busy in doing some lab exercise & find the above logs in debugs. Then I analysed the logs carefully and conclude one thing about C and R value. C stands for local router & R stands for remote router. Above mentioned logs clearly depict that the subnet mask used by remote router is 255.255.255.252 and local router is 255.255.255.0. With addition to this they tell us about the dead and hello intervals of local and remote routers. By analysing the logs you can quickly come on to the conclusion regarding their problems in forming ospf adjacency.
One picture is very much clear from the logs that the link used by router is not serial link because serial link never carries the subnet mask. In case of serial link subnet mask is always used by OSPF is 0.0.0.0.


regards
shivlu jain

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1 comment:

Deepak Arora said...

In short R is for received and C is for Configured