ATM-SGRP (ATM Signaling Group)
Issue 1 May 2002
8-255555-233-143
If no other symptoms are present, no action is required. If layer-3
communication is down:
a. Check for alarms and errors against link components
b. Check out other errors against ATM-SGRP, ATM-TRK, and other
hardware components on the link.
There is no test to clear these errors. The error counter is decremented by
1 every 15 minutes.
b. Error Type 18: the ATM circuit pack has been busied out (either busyout
atm sig-grp or busyout board UUCSS).
1. Release the ATM signaling group (release atm sig-grp) or the
circuit pack (release board UUCSS).
c. Error Type 257: the primary signaling channel connection has been lost for
more than 90 seconds.
■ The associated B channels are placed in the ISDN
Maintenance/Far-End state.
■ The B channels are not usable for outgoing calls, although incoming
calls can be accepted.
■ The switch automatically attempts to recover the signaling link.
1. Pay particular attention to the results of Test #636 (Primary
Signaling Link Hardware Check) in the test sequence.
■ When the link does recover, the B channels are negotiated back to
the In-Service state and their alarms are retired.
2. When this error occurs, the state of the Signaling Group is changed
to out-of-service (verify using the status sig-group command).
d. Error Type 769: signaling link hardware error.
Service-affecting failures of the hardware used to transport the D channel
are reported to the ATM CES Signaling Group MO. Maintenance logs this
error, places the D channel into the OOS state, and raises a board-level
alarm. The D channel is returned to service, and the alarm is retired once
the hardware failure condition clears.
e. Error Type 1281: Degraded PVC alarms indicate that a particular
Permanent Virtual Circuit, or signaling group, has encountered sufficient
errors to exceed firmware thresholds. Operations can continue but at a
lower level of reliability or performance. Firmware filters these alarms so
that only one is reported active at a given time. The following in-line error
is considered a Degraded PVC alarm:
■ Excessive AAL – The AAL layer is experiencing an excessive
number of errors in trying to reconstruct Service Data Units (SDUs).
Possible causes:
— Problem with the ATM switch
— Noisy communication paths on opposite side of ATM switch
— Unhealthy sending node
— Congestion at the ATM switch
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