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EIGRP error - %DUAL-5-NBRCHANGE: IP-EIGRP 1: Neighbor 10.3.250.18 (Gigabit

Hello,

I am seeing the following error in in my router which is configured with EIGRP Protocol.

Can any one tell me what are these logs about.

Sep 29 00:41:56: %DUAL-5-NBRCHANGE: IP-EIGRP 1: Neighbor 10.3.250.18 (GigabitEthernet13/24) is down: retry limit exceeded

Sep 29 00:41:56: %DUAL-5-NBRCHANGE: IP-EIGRP 1: Neighbor 10.3.250.2 (GigabitEthernet13/23) is down: retry limit exceeded

Sep 29 00:41:56: %DUAL-5-NBRCHANGE: IP-EIGRP 1: Neighbor 10.3.250.33 (TenGigabitEthernet12/1) is down: retry limit exceeded

Sep 29 00:41:56: %DUAL-5-NBRCHANGE: IP-EIGRP 1: Neighbor 10.3.250.18 (GigabitEthernet13/24) is up: new adjacency

Sep 29 00:41:59: %DUAL-5-NBRCHANGE: IP-EIGRP 1: Neighbor 10.3.250.33 (TenGigabitEthernet12/1) is up: new adjacency

Sep 29 00:42:00: %DUAL-5-NBRCHANGE: IP-EIGRP 1: Neighbor 10.3.250.2 (GigabitEthernet13/23) is up: new adjacency

Thanks,

Mirza.

4 REPLIES
New Member

Re: EIGRP error - %DUAL-5-NBRCHANGE: IP-EIGRP 1: Neighbor 10.3.2

Hi Mirza,

The above logs shows that the nieghbor is going up or down.

The output Interpretor shows

Explanation: A neighbor has gone up or down.

Recommended Action: No action is required.

If any particular neighbor flaps then please refer to this link http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080094613.shtml.

Regards

Salwa

New Member

Re: EIGRP error - %DUAL-5-NBRCHANGE: IP-EIGRP 1: Neighbor 10.3.2

Hi Salwa,

Thanks for the post.

I am looking for the reason for this issue.

Because there was no issue with the Link or Cable...it has got rectified automatically.

I was referring the below site.

http://www.ciscopress.com/articles/article.asp?p=27839 in which look for table 7.1 & 7.3 for error Retry limit exceeded.

but could not understand , IS it some thing related to Multicast & Unicast in Eigrp?

Thanks,

Mirza.

Hall of Fame Super Silver

Re: EIGRP error - %DUAL-5-NBRCHANGE: IP-EIGRP 1: Neighbor 10.3.2

Hello Mirza,

EIGRP has its own algorithm for managing the process of sending updates to neighbors.

This reliable transport protocol allow to send first try as a multicast.

EIGRP keeps a state and a queue for each neighbor.

If a neighbor doesn't ack the reception of the multicast update within a time, the EIGRP process takes note of this.

Further attempts to send a copy of that update are sent with destination unicast = neighbor ip address.

The device attempts some times to resend the update if all times no ack is received there is a max number of retries.

After max retries expires the EIGRP neighborship is reset because the neighbor is considered not reliable.

Edit:

you can be facing an MTU issue here that causes a specific update of a certain size to be dropped in between the two devices.

if possible you should check on the neighbor if the update packet arrives.

Actually, update size depends on the prefix length of carried routes.

routes with prefix len > 24 takes 4 more bytes to be carried.

This has been explained in a thread of some mounths ago.

Hope to help

Giuseppe

New Member

Re: EIGRP error - %DUAL-5-NBRCHANGE: IP-EIGRP 1: Neighbor 10.3.2

Hello Giuseppe,

Excellent explanation in the above, must be cant get better than this.

As u told this has been explained in earlier can u give me the date and converstaion name so i can further go through it or direct link.

Does this issue occur in the peak utilization or in non-peak hours..

For us we mostly get this in Non-peak hours.

Also if its related to MTU if should continuosly come...Can u explain how can i resolve this error.

At present we havent't assigned MTU on both router for EIGRP configuration.

Thanks,

Mirza.

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