Unusual ATM trouble conditions
Issue 4 May 2002
5-97555-233-123
— There may be other CBR virtual circuits between A500 ports that are
not associated with DEFINITY port networks. A common CBR
application is Circuit Emulation, in which T-1, T-3, etc. circuits are
carried over ATM.
Unusual ATM trouble conditions
There are a few failure modes in the DEFINITY/A500 combination that are difficult
to diagnose. One example is that you can’t make a completely successful call,
even though most indications from DEFINITY and the A500 look good. This
section documents some steps may help diagnose the following failure modes:
■ Incorrectly typed or omitted EPN Route or End System Identifier (A500)
■ Swapped Routes, End System Identifiers, or Fiber between a PPN and an
EPN
■ Swapped Routes, End System Identifiers, or Fiber between A and B side
TN230Xs on an EPN
■ Swapped Routes, End System Identifiers, or Fiber between two EPNs
Incorrectly typed or omitted EPN Route or End
System Identifier (A500)
Symptoms
Talk paths are one-way, from the PPN to the EPN: you can hear tones from the
PPN end station to the EPN end station but not vice versa. Because the signaling
channels are bidirectional virtual circuits (VCs) established from the PPN to the
EPN, these can be routed correctly and come up just fine. Talk paths are two
unidirectional virtual circuits, so a single call has one VC from the PPN to the EPN
(which is routed correctly) and one VC from the EPN to the PPN (which cannot be
routed).
Diagnostics
1. At the A500 type show signaling routes or show signaling esi to check
the ATM addresses.
2. Use show signaling stats port q93b on the EPN port and look for Cause
Code 3 (No route to destination).
Action
1. Correct the ATM address translations in the A500.
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