Consequence of changing EIGRP router-ID?

[jmaxwellUSAF]

Hello.

On a production routing device, if change the EIGRP router-ID, what will be the consequences?

My specific admin issue-- When i use command

sh ip eigrp topology A.B.C.D /24

to see the originating router, I often an given an IP that I don't recognize; thus, I'd like to solve this by changing/creating human-logical recognizable router-id's on each device.

But, I worry that if I do this I will crash the network, because maybe the EIGRP neighbor association will break, or at least churn the network.

Please advise on best solution?

Thank you.

[MHM Cisco World]

no only sure that you dont use router-id conflict with other router.
note:- may be you need

clear eigrp

process to make new router-id take effect

[jmaxwellUSAF]

My specific admin issue-- When i use command

sh ip eigrp topology A.B.C.D /24

to see the originating router, I often an given an IP that I don't recognize; thus, I'd like to solve this by changing/creating human-logical recognizable router-id's on each device.

But, I worry that if I do this i will crash the network, because maybe the EIGRP neighbor association will break, or at least churn the network.

Please advise on best solution?

Thank you.

[DanielP211]

Hello!

You can change the router-ID (the EIGRP router ID is chosen as the highest IP address on an active interface on the router, unless loopback interfaces are configured). 
If you change it the router-id the neighbors will form back on the new router-id's (you might want to do a

clear ip eigrp

neighbors) but there won't be any issue because the in connecting interfaces will remain the same...

Just make sure you don't duplicate router-id's!

[MHM Cisco World · Accepted solution]

I make lab and test, 
your you use router-id the EIGRP immediately take effect NOT until you do

clear ip eigrp

process. 
see the neighbour is Down/Up 
just want to clear this point 
thanks 
MHM

[jmaxwellUSAF]

Thank you for your inspired effort MHM!

QUESTION: How much time elapses before an EIGRP neighbor reports to its upstream neighbors that a downstream neighbor is offline? (In the above picture, the adjacency restores in less than a second. Did the next hop upstream router send information throughout the network that the downstream router was offline?)

Thank you.

[MHM Cisco World]

I will share debug of EIGRP notify in all router, it will give clear view of EIGRP behave when router-id change 

[MHM Cisco World]