DEFINITY Enterprise Communications Server Release 7
Maintenance for R7r
555-230-126
Issue 4
June 1999
Alarms, Errors, and Troubleshooting
5-86Packet Bus Fault Isolation and Repair
5
packet bus failure a catastrophic problem. The only way an EPN packet bus
failure can affect TDM traffic is via possible impact on system response time in a
large switch due to running of ISDN-BRI endpoint maintenance. This should
rarely happen because the packet bus maintenance software is able to prevent
this for most faults (see the next section).
If packet bus failure occurs in the PPN, the impact is much more widespread.
Because the PPN packet bus carries the signaling and control links for all EPNs,
PPN packet bus failure effectively removes all the EPNs from service, including
both TDM and packet busses. Packet bus traffic in the PPN is also disrupted.
!
CAUTION:
Packet bus fault correction and fault isolation often involve circuit pack
removal, which is destructive to service. Minimize time devoted to
destructive procedures by the use of non-destructive ones where possible.
Packet Bus Maintenance Software
Packet bus maintenance software involves the usual set of maintenance object
error conditions, tests, and alarms. These are described in “PKT-BUS” in Chapter
9. Because a packet bus failure can cause all BRI/ASAI endpoints in the affected
Port Network, and all their associated ports and circuit packs, to report failures,
special care must be taken to ensure that the flood of error messages does not
overload the system and interfere with TDM Bus traffic.
When such a failure
occurs
, circuit pack maintenance is affected in the following manner:
■ In-line errors for the following MOs which indicate possible packet bus
failures are logged but
not acted upon:
BRI-BD, PGATE-BD, PDATA-BD,
UDS1-BD.
■ In-line errors for the following MOs which indicate possible packet bus
failures are
neither logged nor acted upon:
BRI-PORT, ABRI-PORT,
PGATE-PT, PDATA-PT, ISDN-LNK.
■ All in-line errors for the following MOs are
neither logged nor acted upon:
BRI-SET, BRI-DAT, ASAI-ADJ.
■ Circuit pack and port in-line errors that are not related to the packet bus,
or that indicate a circuit pack failure, are acted upon in the normal fashion.
■ Periodic and scheduled background maintenance is not affected.
■ Foreground maintenance (for example, commands executed from the
terminal) is not affected.
These interactions allow normal non-packet system traffic to continue unaffected,
and they reduce the number of entries into the Error/Alarm Logs. If the packet
bus failure is caused by a failed circuit pack, errors against the circuit pack
should appear in the Error/Alarm Logs as an aid for fault isolation. The above
strategy is implemented when:
■ In-line errors indicate a possible packet bus failure reported by two or
more Packet circuit packs.
