I have two routers(7201 and 3700) connected with a switch (3550) in between. I have EIGRP running with a GRE tunnel in between. One switch constantly claims EIGRP neighbor up and down. The neighbor is the IP adddress of the tunnel interface. Debug EIGRP shows no other messages on that router but debug on the other router reveals the message that EIGRP messages not responded to. Seen this? Resolution?