One more thing to add...
If a loopback plug is inserted in the smart jack at either the A or Z end,
the router at the other end sees the loop and can run patterns (all 0's,
alternating 0's/1's, all 1's) across the loop. Remove the loopback plug
and plug the routers back in, and the line proto starts flapping again.
Trun off keepalives, and the protocol stays up, but neither router sees
packets sent by the other.
Bell is supposed to be having someone make sure the framing/line coding is
properly set in the DACS and any other equipment the circuit goes through.
On Wed, 26 Dec 2001 jlewis@lewis.org wrote:
> I've got an odd T1 problem I've been unable to solve remotely. It's a
> BellSouth point to point T1 between 2 locations in the same city. Cisco
> 1600 and Digital Link Prelude at the Z end, 2620 with WIC-2T and Larscom
> Access-T's at the A end. All of a sudden, line protocol (we're using
> hdlc) is flapping on both sides. i.e.
>
> Dec 26 19:13:58: %LINEPROTO-5-UPDOWN: Line protocol on Interface
> Serial0/3, changed state to down
> Dec 26 19:14:00: %LINEPROTO-5-UPDOWN: Line protocol on Interface
> Serial0/3, changed state to up
> Dec 26 19:14:28: %LINEPROTO-5-UPDOWN: Line protocol on Interface
> Serial0/3, changed state to down
> Dec 26 19:14:30: %LINEPROTO-5-UPDOWN: Line protocol on Interface
> Serial0/3, changed state to up
>
> This site is a couple hundred miles away, and though I don't have anyone
> technical there, there is a person able to move wires around. I had them
> move the T1 patch cable to another CSU on another WIC-2T port and it kept
> doing this...so that eliminates the CSU and WIC port.
>
> I've had bell loop the circuit towards the A side and towards the Z side,
> and have been able to run extended pings with various patterns across each
> half of the circuit. When they reconnect the A and Z ends in the DACS,
> line protocol goes back to flapping. Until it failed, this circuit had
> been in use for quite a while, so I don't suspect CSU config issues.
>
> All equipment at each end has been power cycled.
>
> I haven't tried having the remote people replace patch cables, but I
> wouldn't think each half of the circuit would have tested ok if there was
> a bad cable.
>
> Anyone have any idea what this might be? I really don't want to do it,
> but I've run out of ideas other than grabbing enough spare gear to replace
> everything at each end and driving up there to replace all the gear and
> wiring.
>
>
-- ---------------------------------------------------------------------- Jon Lewis *jlewis@lewis.org*| I route System Administrator | therefore you are Atlantic Net | _________ http://www.lewis.org/~jlewis/pgp for PGP public key_________
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