Notification for EIGRP path selection-How?

Unanswered Question
Nov 30th, 2008

Hi All,

Our Cisco 3560 Layer 3 has two WAN connection, one connection is over the ATM network (primary path) and another one is over the ADSL backup connection via Cisco 877 through VPN tunnel. Sometimes it has happened that EIGRP chooses the ADSL backup path over the ATM connection,though there was no EIGRP neighbor failure on the syslog message(but I know for a fact that ATM connection had a problem where there was no data passing). EIGRP did the right thing choosing the ADSL backup. We use SolarWinds to alert by analyzing syslog message. But on this case, we didn't know when the ADSL backup path was switched. Is there any way to know which EIGRP path is in use at the current state? Thanks.

I have this problem too.
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Richard Burts Sun, 11/30/2008 - 16:42


It is not clear to me from your post whether the configuration of your 3560 has enabled logging of EIGRP neighbor changes or not. Can you clarify this? While it should be possible to access the 3560 and interrogate its routing table, I would think that the best solution would be to watch for EIGRP neighbor state changes.

There is also the possibility to consider that something could be inteferring with receipt of syslog messages by Solarwinds (perhaps loss of connectivity between the 3560 and the Solarwinds device). Perhaps the way to check on that possibility is to be sure that logging buffered is enabled on the 3560 (with sufficient memory allocated for the buffer) then when there has been an episode of EIGRP choosing the other route to check on the logging buffer to see if there are messages there that Solarwinds did not receive.



shawkatalvi Sun, 11/30/2008 - 18:58

Thanks Rick.

3560 has enabled logging of EIGRP neighbor changes. I checked the syslog on 3560 while the fault continued, there was no syslog message as to why that Neighbor failed. show ip eigrp neighbors showed that the path did not exist. Is there any why to know when eigrp chooses which eigrp path?


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