OSPF virtual-link issue

I am working on R&S V5 advance technology lab and I ran into a issue.
I've virtual link configured b/w R6-R1 and transit-capability is off. I've also configured virtua-link between R3-R2. problem arise when next day i have started my lab again. Virtual link started to flap and went down and wasn't coming up and keep giving the following message on cli.
%OSPF-4-ERRRCV: Received invalid packet: mismatched area ID from backbone area from, GigabitEthernet0/1.23

because i have doing authentication md5 lab for multiple keys, I thought this issue is related to it but i spent lots of time couldn't figure out why it was happening then I realised when i started the lab due to R2 was configured with a higher loop back IP its selected as router-id instead of and when i manually converted back to its started working again as it was expected but I don't get what was the actual issue as I am not very good in OSPF. if someone could help me figure out why this behaviour was happening. Just to add as per the original technology labs there is no manual config of Router-ID anywhere. when it select R2 router id virtual link never comes up.
output of OSPF data base from R3:please see the attached file

output of OSPF data base from R2:please see the attached file

now after config manual router id on R2 and clear process see the output or R2 and R3 OSPF DB and configuration or R5, R2 & R3 for review: please see the attached file

Sorry for a long post - Please if someone help me understand why this was happening and what was the technical issue ?

Best Answer

  • tehmertehmer ✭✭
    Accepted Answer

    I think I've got the answer. when the virtual link is create router-id was the default loop back address given in the configuration and when I progressed further for other labs. I have configured higher loop back IP addresses and latter the day, when the ospf process was reset it took highest loopback 100 as the router-id because there was not router-id command exclusively was configured and it end up broke the virtual link which was configured to use lo0 as the router-id.


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