DEFINITY Enterprise Communications Server Release 7
Maintenance for R7r
555-230-126
Issue 4
June 1999
Maintenance Object Repair Procedures
9-957ISDN-TRK (DS1 ISDN Trunk)
9
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) 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) for transmission
through the system. Keep this hierarchy of dependencies in mind when
diagnosing problems.
DS1 ISDN Trunk Service States
The
status trunk
command displays the following possible service states for
ISDN trunks. Table 9-366
gives recommended procedures for each state.
■ In-Service (INS)
The B-channel is in its normal operating state.
■ Out-of-Service/Far-End (OOS/FE)
A B-Channel is initialized to this state when administered. The switch
sends messages to the far-end to negotiate the B-channel into service. If
the far-end does not respond to the messages within a certain time period,
then the service state remains out-of-service and maintenance will
periodically resend the messages. The trunk is unusable for incoming and
outgoing calls.
■ Out-of-Service/Near-End (OOS/NE)
This is the state of the trunk when the NPE Crosstalk Test fails or when the
trunk is busied out by system technician. In this state, the trunk is
unusable for incoming or outgoing calls. No messages are sent to the
far-end until the signaling link comes back into service or the trunk is
released by system technician.
■ Maintenance/Far-End (MTC/FE)
This state is reached when the far-end does not respond to messages
sent over the signaling link for a particular trunk after a certain amount of
time. This state is different from OOS/FE since the signaling link must have
initially been up and the B-Channels in-service. The switch will periodically
send messages to the far-end to try to negotiate the trunk (B-channel) into
service. The trunk is unusable for outgoing calls but will service incoming
call requests from the far-end. Note that transitions into MTC/FE do not
drop stable calls. Therefore, if the service state changes from in-service to
MTC/FE, then stable calls are unaffected.
