Eigrp router id configuration for 2 difference eigrp process id routing redistribution

[timothy1972]

Hi All,

   I need to setup a router configured with eigrp process id 2 on WAN interface and Internal LAN interface configured with Eigrp process id 1. since they are running in difference process id, i need to configure mutual redistribution between process id 1 and process id 2 in order for outside WAN network to talk to inside LAN network.

But I am confused with the process eigrp process id configuration. Can i configure the same router id into 2 difference eigrp process id and redistribute them to each other ? or i should configure 2 loopback interface, assigned one of the loopback ip to process id 1 as eigrp router id and another loopback interface assigned as eigrp router id for eigrp process id 2? will it cause any issue or make any difference?

Thanks a lots for the reply in advanced

Option 1:

interface loopback 0

ip address 172.16.16.1

router eigrp 1

network 10.1.1.0 0.0.0.255

no auto-summary

eigrp router-id 172.16.16.1

redistribute eigrp 2

router eigrp 2

network 192.168.1 0.0.0.255

no auto-summary

eigrp router-id 172.16.16.1

redistribute eigrp 1

Option 2:

interface loopback 0

ip address 172.16.16.1

interface loopback 0

ip address 172.16.16.2

router eigrp 1

network 10.1.1.0 0.0.0.255

no auto-summary

eigrp router-id 172.16.16.1

redistribute eigrp 2

router eigrp 2

network 192.168.1 0.0.0.255

no auto-summary

eigrp router-id 172.16.16.2

redistribute eigrp 1

Regards,

Timothy72

[John Blakley]

Edward,

I don't think you'll have a problem using the same router-id for both processes. I labbed this up and I was able to get routes to both sides of the link using a router id of 1.1.1.1. The routes came in fine, and I don't believe you'll have an issue. The only time that I think there's a problem, and I'd have to lab this up, is when you are trying to establish a neighborship with a router that has the same router-id as yours. It's recommended that you have a different router id per router, but I don't believe it's per process.

HTH,
John

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[Richard Burts]

Timothy72

I have experienced the situation in a customer network where two routers were using the same router ID. I can certainly say that it did create problems in which prefixes advertised by router A were not accepted by router B. So very clearly different routers require different router ID.

I have not experienced the situation with 2 processes on the same router using the same router ID and so can not speak from experience about this. But based on my experience I would be more comfortable with your option 2 where each process has a unique router ID.

HTH

Rick

[paul driver]

hello

I am aware there is also way to prohibit advertising redistributed routes in a eigrp routing domain by setting the same router ids to each peer. so given this I would have to agree with Richard a possible routing issue would arise in you're scenario also

example:
router eigrp xx
eigtp router -id 11.11.11.11 ( same router id on each router)

When routes are redistributed into eigrp, the external routes are tagged with the router-id of the router that
originated the route/s and if the recieving router sees its own router id in the update it rejects the route

Res
Paul

Sent from Cisco Technical Support iPad App

[corabeus81]

Hello, there is an issue regarding duplicate router-id in EIGRP  but it appears when 2 routers in the same AS have the same router-id and redistribution is used (http://www.cisco.com/c/en/us/support/docs/ip/enhanced-interior-gateway-routing-protocol-eigrp/18685-eigrp-dup-id.html)

in our case i agree with John Blakley that this should work

[Richard Burts]

Since it has been several months since the original question came up, I wonder if Timothy72 can tell us if he implemented it and if so what results did he get?

HTH

Rick