eigrp problem (retry limit) - mtu size?

Unanswered Question
Mar 31st, 2007
User Badges:


i have a problem regarding eigrp.

i have eigrp enabeld between two routers which are connected over frame-relay.

since yesterday i have the problem that i always get the message "neighbor down - retry limit exceeded".

i know that the problem is that on router does not get an ack from the other side - but why?

if i decdrease the mtu to 1450 "mtu 1450" - everything is ok - if i change back to defaultvalue - after 16 retrys the neighpor is down again.

so my question is how does the mtu size of the interfaces influence the eigrp neighborship ?

till now we have the workaround with the mtu 1450 - but what is the problem ?

thanks for answer!

thx for answer

  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 0 (0 ratings)
royalblues Sat, 03/31/2007 - 04:35
User Badges:
  • Green, 3000 points or more

Is the MTU value the same on both the sides?

Also can you try and extended ping with 1500 bytes over the frame-relay?


rabeder Sat, 03/31/2007 - 04:42
User Badges:


in the case where it does not work, there is no "mtu xx" configured - so its default - and i assume that the defaultvalue is 1500 - on both sides.

today i hav no access to the routers, otherwise i could do a "sh ip int xy" - to check the actual mtu size if no "mtu xx" is configured.

i did an extended ping with 1500 and it was ok!

royalblues Sat, 03/31/2007 - 04:53
User Badges:
  • Green, 3000 points or more

I dont know of any issues with the default MTu size and EIGRP.. I will wait for you interface output


rabeder Sat, 03/31/2007 - 04:58
User Badges:

thanks royalblues,

i will give some outputs on monday, 2 april

jafar.tarawneh@... Tue, 05/22/2007 - 13:59
User Badges:

we ran into the same issue, our code is 12.4.12

atm-frame connection, you need to match the MTU to avoid, and fix this issue.


This Discussion