2 Replies Latest reply: Sep 10, 2010 9:23 PM by Keith Barker - CCIE RS/Security, CISSP RSS

    DMVPN with EIGRP Problem




      I am configuring Dymanic Multipoint VPN (with multipoint GRE tunnels) with EIGRP, between 3 routers in lab environment, and I have the following problem:


      I have one PC on the internal subnet of each router and I configured the PCs to continously ping to each other, using their private/internal IP addresses. On one of the spokes, I disconnect the physical inteface which is the Tunnel source for the multipoint tunnel, and in a few seconds I connect the interface back. In a few seconds, the connectivity is fixed again, the dynamic tunnel(s) are reconstructed automatically, I can see the EIGRP neighbors, and the PC connected to that router can communicate with the other PCs.


      If I do the same on the HUB router (disconnect the physical itnerface which is the tunnel source for a few seconds and then connect it again), I have to wait for about 10 minutes in order for the dynamic tunnel(s) to be reconstructed again and to see the two spoke routers as EIGRP neighbors. After about 10 minutes, the DMVPN connectivity is ok again. Do you know how can I solve this issue?


      From each router I am advertising (with EIGRP) only the subnet of the tunnel interface and the internal subnet of the router (where the PCs are connected) .I also I disabled split-horizon for EIGRP on all the tunnel interfaces. Is there any counter related to NHRP/mGRE/EIGRP that forces the hub router to wait for 10 minutes to reconstruct the DMVPN if the physical interface of the tunnel is restarted?


      I attach the debug output of the Hub Router, after the interface is disconnected and reconnected again.