User Guide

DEFINITY Enterprise Communications Server Release 5
Maintenance and Test for R5vs/si
555-230-123
Issue 1
April 1997
Maintenance Object Repair Procedures
Page 10-819ISDN-TRK (DS1 ISDN Trunk)
10
For interfaces using country protocol 1 on the DS1 Circuit Pack administration
form (including US), the signaling protocol used for the maintenance of the
B-channel is defined by the AT&T ISDN-PRI Specification.
For interfaces using country protocols other than 1, the signaling protocol used
for the maintenance of the B-channel is defined by the CCITT ISDN-PRI
Specification.
There are five possible SERVICE STATES for a B-channel. The service state is
negotiated with the far-end switch, changes over time, and may have a far-end or
near-end component. The service state is initialized to Out-Of-Service/Far-End
state and an attempt is made to negotiate it to In-Service.
NOTE:
The service state of a particular DS1 ISDN Trunk B-channel can be
displayed by issuing the status trunk <trunk_group/trunk_member>
system technician command.
If a call is present, the Specification defines the permissible CALL STATES as
well. There are tests in the Short and Long Test Sequences for DS1 ISDN Trunk
designed to audit these states and ensure agreement between both ends of the
PRI connection.
Alarming Based on Service States
A warning alarm is logged against a DS1 ISDN B-channel trunk when it is placed
in the Maintenance/Far-End or Out-Of-Service/Far-End states, during which the
trunk is unusable for outgoing calls. When a warning alarm is present, use status
trunk group#/member# command to determine the exact state. Other alarms
can be diagnosed by using the short and/or long test sequences. Note that an
ISDN B-channel trunk can be placed in a Far-End service state by either action
taken by the far-end switch or by failure of the far-end switch to respond. For
example, if the far-end does not respond to a Remote Layer 3 Query (Test #637
for ISDN-SGR), the associated DS1 ISDN trunk B-channels will be placed in the
Maintenance/Far-End service state.
As a port on a DS1 circuit pack (DS1-BD or UDS1-BD), and as part of a signaling
group dependent on a D-channel (ISDN-LNK/ISDN-PLK) for signaling, operation
of the ISDN-TRK is dependent on the health of these other maintenance objects.
The ISDN D-channel in turn depends on the Packet Bus (PKT-BUS)/Processor
Interface Link (PI-LINK) (dependent on setup) for transmission through the
system. Keep this hierarchy of dependencies in mind when diagnosing
problems.