eigrp broadcast netowrk type!

[MohammadSalih]

hi every one

can i enable eigrp on more than one router with the same subnet  ( broadcast network type )?

when i enable it the link goes up and down?

[Jon Marshall]

Can you give an example. 

You have to use a common subnet between EIGRP neighbors for the adjacency to come up so not sure what you are asking. 

Jon

[MohammadSalih]

thanks for replaying ,

i have 4 router they have subnet 192.168.20.1-4/24 , they are connected to same vlan and each router reach to the other one ,

when i enable eigrp on the routers it shows the neighbor comes up , after while goes down and come up again .

stuck in this situation .

[Giuseppe Larosa]

Hello @MohammadSalih ,

are these real routers or you are emulating the topology in GNS3 or other tool ?

if in real world you need to check the STP mode you are using on the switchports associated to the VLAN.

if not using spanning-tree portfast and using old PVST mode the adding of a new neighbor can cause an STP recalculation that can cause the current EIGRP neighbors to time out and then to form again the neighboship.

So I would suggest to investigate STP on the LAN switch.

In theory for EIGRP adding a new neighbor does not cause any flapping

Hope to help

Giuseppe

[MHM Cisco World]

yes sure you can do that but 

no auto summary prevent neighbor flapping.

[Richard Burts]

I agree with Jon that we need more information to be able to understand what the original poster is trying to ask. It would be nice to have the full running config. But at a minimum I believe that we will need the configuration of the interfaces and the configuration of eigrp (from both devices). It would also be helpful to see the output of show cdp neighbor from both devices.

[MohammadSalih]

Hi,

i have 4 router they have subnet 192.168.20.1-4/24 , they are connected to same vlan and each router reach to the other one ,

when i enable eigrp on the routers it shows the neighbor comes up , after while goes down and come up again .

stuck in this situation .

[paul driver]

Hello
What do the eigrp logs show when the eigrp peering is torned down?
Can you post a simple topology diagram , maybe this can assist with providng you with a solution

router eigrp
eigrp-log-neigbour-change

show logging

[MHM Cisco World]

two troubleshooting steps

1- ping 224.0.0.10 <- this must reply form all eigrp neighbor.

ping success 

2-ensure that you not config passive-interface between eigrp peer.