EIGRP off-set list is not adjusting routing metrics

[Ricky S]

Hi folks, we have a stack of Cisco 3750s serving as our core switch in the data center. We have two separate routers (Primary and Secondary) that connect to our remote branch offices via DMVPN tunnels. Both routers at the core and the switch are running EIGRP and communicate with each other in VLAN123. Until yesterday, I had Secondary router configured with an off-set list that increased the EIGRP route metrics by 100 before advertising it out GigabitEthernet0/2 (connecting to the switch). Did not have any off-set lists for advertisements coming from the Primary router to intentionally force the switch to populate it's routing table with the information from Primary router. Secondary router was always the feasible successor for all the routes.

Since yesterday, for some reason, the advertisements from the Primary and Secondary both have the exact same metrics. Off-set list is still in place but it seems like it's not adding a 100 to the metrics as before. Here is a quick output of the ROUTER EIGRP 1 section of the Secondary router.

router eigrp 1

network 10.10.201.0 0.0.0.255

network 172.18.123.0 0.0.0.255

network 192.168.155.253 0.0.0.0

redistribute static route-map STATIC-TO-EIGRP

offset-list 99 out 100 GigabitEthernet0/2

!

interface GigabitEthernet0/2

ip address 172.18.123.3 255.255.255.0

ip hello-interval eigrp 1 3

ip hold-time eigrp 1 10

!

access-list 99 permit any

!

***Here is a truncated output of sh ip eigrp topology from the core switch. Notice both successor and feasible succesor are advertising same metrics

P 192.168.166.0/24, 1 successors, FD is 1433856
        via 172.18.123.2 (1433856/1433600), Vlan123
        via 172.18.123.3 (1433856/1433600), Vlan123
P 10.32.0.0/24, 1 successors, FD is 1305344
        via 172.18.123.2 (1305344/1305088), Vlan123
        via 172.18.123.3 (1305344/1305088), Vlan123
P 192.168.155.204/32, 1 successors, FD is 1433088
        via 172.18.123.2 (1433088/1432832), Vlan123
        via 172.18.123.3 (1433088/1432832), Vlan123

!

!!

If anyone can provide any assitance, that'll be much appreciated.

Thanks everyone

[Abzal]

Hi,

Try to change access-list:

no access-list 99

access-list 99 permit 10.32.0.0 0.0.0.255

access-list 99 permit host 192.168.155.204

access-list 99 permit 192.168.166.0 0.0.0.255

Hope it will help.

Best regards,
Abzal

[Richard Burts]

If the offset list was working, as the original poster says, and then it stopped working, then I am not confident that changing the syntax of the access list will be effective in solving the issue.

If the offset list was working and then it stopped, then it suggests that something changed. Can the original poster tell us if there were any changes in the network? (were there any code upgrades, or config changes, or connectivity interruptions, etc)

Perhaps it might be helpful if the original poster could give us the output of show ip eigrp neighbor from both routers and from the core switch.

If you were to do a shutdown and a no shutdown of the interface Gig0/2 of the secondary router does the behavior change?

HTH

Rick

[Ricky S]

I have a TAC cased opened on this for last 3 days. Cisco tech had told me he was testing this configuration out in his lab but hasn't gotten back to me since.

Only thing that was changed, was the IOS upgrade on both Primary and Secondary routers to the latest 15.2(4)M2

version. It smells like a bug in the new image because I tested the same configuration in my home lab with 2 Cisco 1811 routers and a switch and it works fine.

I haven't tried a shut/no shut on gige0/2 as I wanted to wait to see what Cisco writes back.

[Richard Burts]

Knowing that there was a code upgrade on the routers is certainly significant. I would agree that it sure does suggest that it is a bug in the new code. In that case I am less inclined to try the shutdown and no shutdown. Hopefully the TAC will find an answer. Please do update us as there is any progress with this issue.

HTH

Rick

[Kevin Dorrell]

What were you upgrading from? I don't remember the full details but isn't there a move to the so-called wide metrics?

I had a look for how offset works with EIGRP, and it seems it only affects the delay metric.

http://cciepursuit.wordpress.com/2008/12/30/secrets-of-the-eigrp-offset-list-command/

I am not sure whether that is true with the new wide metrics.



I http://cciepursuit.wordpress.com/2008/12/30/secrets-of-the-eigrp-offset-list-command/


Sent from Cisco Technical Support Android App

[Ricky S]

Upgraded from 151-1.T

Yes off-set list would skew the delay metric and has worked perfectly well in our environment until now.

I don't want to start fooling around with the K values until I have confirmation and/or resolution of a possible bug with this IOS from Cisco.

I'll keep you all posted.

[Kevin Dorrell]

As you can guess, I'm still getting used to my new smartphone ;-)


Sent from Cisco Technical Support Android App

[Ricky S]

To those who are interested: This issue is now resolved.

I worked with Cisco TAC for a couple of days and they concurred this to be a bug in the above mentioned IOS.

Upon their advice, I downgraded my IOS version and all seems to working well i.e. the off-set list is now accurately incrementing the advertised distance by appending whatever value I configured for it. Here is an example:

****ROUTER****

router eigrp 1

network 10.10.201.0 0.0.0.255

network 172.18.123.0 0.0.0.255

network 192.168.155.253 0.0.0.0

offset-list 99 out 100 GigabitEthernet0/2

!

access-list 99 permit any

!

!

****EIGRP TOPOLOGY OUTPUT FROM CORE SWITCH***

P 172.26.0.0/16, 1 successors, FD is 1308416
via 172.18.123.2 (1308416/1308160), Vlan123
via 172.18.123.3 (1308516/1308260), Vlan123
P 172.18.27.0/24, 1 successors, FD is 1308416
via 172.18.123.2 (1308416/1308160), Vlan123
via 172.18.123.3 (1308516/1308260), Vlan123
P 192.168.155.66/32, 1 successors, FD is 1433088
via 172.18.123.2 (1433088/1432832), Vlan123
via 172.18.123.3 (1433188/1432932), Vlan123

!

!

Thanks everyone for your assistance.