The HDLC T1 leased line that we use to connect to a partner's site, has always been working fine. Recently, in several occasions, some Telco's problems brought the protocol down on our serial interface, but the remote partner's serial interface didn't notice the event and kept the prococol up. Remote HSRP did not activate the standby router and the 2 sites became disconnected. I know this can appen with frame-relay and DSL connections, but I didn't expect from point-to-point Leased lines. Shutting down administratively our serial interface finally brings down the remote line protocol. Telco's support says that everything is OK on their side and debugging HDLC at both ends during normal operations shows two consistent sequences of packets; the keepalives are of course set. Should I change the remote serial interface?
I have this problem too.