Routing EIGRP missing

[faeznakaius]

I have one network uisng bgp for WAN and eigrp for LAN for a customer. For HQ and branch, i used routing eigrp for the LAN conection from HQ to branch and from branch to HQ.

HQ have one tunnel connection to the branch.Tunnel also using eigrp.Branch also have one tunnel to HQ.

Connection from branch to HQ and HQ to branch working good. But after 2 weeks, i found that the LAN connection to the HQ lost.When show ip route at the HQ, i can't see the LAn network segment.But at the branch network for LAN segment still in the router eigrp. Tunnel to HQ at the branch still up.But ping LAN to LAN from HQ to branch and branch to HQ failed.

My questions as below:

1)Need your advise on why is the network LAN segment of the branch missing and couldn't see from the HQ?

2)What are the course of the problem ?

3) What should i do in order to prevent the problem to happen again?

[Rick Morris]

I would like to break this down in chunks.

EIGRP between sites works when link is up.

-These sites have a DMVPN tunnel between them

As long as the tunnel is up the EIGRP Table will be populated with the networks. When the link is down you should lose these, not right away but eventually the table should be purged. When the link comes back up you should form a new adjacency and the table will be populated again.

What you are saying is the link goes down and only one side shows the EIGRP routes still?

You cannot ping, which should be the case because the one side is down.

Is it the link or the BGP session that is down?

I am a little confused by everything and need to approach this in little bits rather than one large brain dump.

When you say LAN link is down, what do you mean? Is it the switch connection to the router, your host to the switch, etc... Or do you mean the tunnel is down?