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DEFINITY Enterprise Communications Server Release 7
Maintenance for R7r
555-230-126
Issue 4
June 1999
Alarms, Errors, and Troubleshooting
5-83Packet Bus Fault Isolation and Repair
5
■ TN464F Universal DS1 circuit pack
[UDS1-BD, ISDN-LNK] supports
ISDN-PRI communications over an attached DS1 facility. It transports of
D-channel signaling information over the packet bus, and B-channel data
over the TDM bus. The Universal DS1 circuit pack has the same fault
detection capabilities as the TN570 Expansion Interface.
■ TN771D Maintenance/Test circuit pack
[M/T-BD, M/T-DIG, M/T-PKT,
M/T-ANL] is the workhorse of packet bus maintenance. This circuit pack
can detect all packet bus failures for the Port Network in which it resides.
In Critical Reliability systems (duplicated PNC), this circuit pack enables
the reconfiguring of the packet bus around a small number of failed leads.
The TN771D circuit pack provides a standalone mode (one that does not
involve communication with the SPE), for inspecting the packet bus for
faults. Standalone mode is a critical tool for troubleshooting packet bus
faults.
NOTE:
All Maintenance/Test circuit packs must be of vintage TN771D or
later. This circuit pack is also used for ISDN-PRI trunk testing
(M/T-DIG) and ATMS trunk testing (M/T-ANL).
Effects of Circuit Pack Failures on the Packet Bus
Certain failures of any of the above circuit packs can disrupt traffic on the packet
bus Some failures cause packet bus failures with corresponding alarms, while
others cause service outages without alarming the packet bus, (although the
failed circuit pack should be alarmed).
Packet bus circuit pack failures affect the bus in the following ways:
■ TN1655 Packet Interface
. A failure of the Packet Interface typically
causes all Packet traffic in the system to fail. As a result,
— Expansion Port Networks and Center Stage Switches are disabled.
— ISDN-BRI sets are not able to make or receive calls.
— Communication with ASAI adjuncts fail
— X.25 communications with external adjuncts fail.
— System Ports are disabled.
— ISDN-PRI D-channel signaling is disabled.
If the failure is on the packet bus interface, the packet bus may be
alarmed as well.
In a system with duplicated SPEs, there is one TN1655 Packet Interface in
each SPE. If a Packet Interface failure in the active SPE causes a packet
bus disruption, an SPE interchange may restore service. In other cases,
replacement of the circuit pack may be required before service is
restored.