[c-nsp] DS3 circuit error

[Pete Templin]

Oddiraju, Kiran @ London SMC wrote:

> Our T3 controller is down and the SP has asked me what I am seeing on my
> end. Below is the show controllers command on my router. Could you tell
> me where the problem is based on the output below? 
> 
> Router#sh controllers t3
> T3 3/0 is down.
>   Applique type is Subrate T3
>   Description: Carrier_Circuit_ID  
>   Transmitter is sending remote alarm.
>   Receiver is getting AIS.

You're seeing AIS from the carrier and sending 'remote alarm' because of 
the inbound AIS.

My circuit-fu is a little rusty, but I think this means that the inbound 
side of the circuit is good end-to-end, but the outbound side of the 
circuit has a problem between your end and the other end.  The far-side 
router (or whatever) is seeing an LOS/LOF/xxx and is announcing that to 
your router.

Middle of circuit, towards far side:
<something's broken>

Far side of circuit:
<bad-DS3-error> into router
AIS out of router

Circuit, towards near side:
AIS (indicates problem on opposite side of circuit)

Near side of circuit:
AIS into router (opposite direction is bad)
<remote-alarm> out of router (acknowledging same-direction alarm to carrier)

pt