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 p laced in a Far-End service state b y either action
taken by the far-end switch or b y failure of the far-end switch to respo nd. For
example, if the far-end does no t respond to a Remote Layer 3 Query (Test #637
for ISDN-SGR), the associated DS1 ISDN trunk B-channels will be plac ed in the
Maintenance/Far-End service state.
As a port on a DS1 circuit pac k (DS1-BD or UDS1-BD), and as part of a signaling
group depend ent on a D-channel (ISDN-LNK) for signaling , operation of the
ISDN-TRK is dependent on the health of these other maintenanc e objects. The
ISDN D-channel in turn depend s on the Packet Bus (PKT-BUS) for transmission
through the system. Keep this hierarchy o f dependenc ies in mind when
diagnosing p roblems.
DS1 ISDN Trunk Service States
The status trunk command d isplays the following possible service states for
ISDN trunks. Table 9-366 gives recommended proce dures 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 ad ministered. The switch
sends messages to the far-end to negotiate the B-channel into servic e. If
the far-end does not respond to the messages within a cer tain time period,
then the service state remains out-of-service a nd maintenance will
periodically resend the messages. The trunk is unusable for inc oming 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 messag es are sent to the
far-end until the signaling link comes back into servic e or the trunk is
released by system technic ian.
■Maintenance/Far-End (MTC/FE)
This state is reached when the far-end d oes not respond to messages
sent over the signaling link for a p articular trunk after a certa in 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 p eriodically
send messages to the far-end to try to negotiate the trunk (B-ch annel) into
service. The trunk is unusable for outg oing calls but will se rvice incoming
call requests from the far-end. Note that transitions into MTC/FE do not
drop stable ca lls. Therefore, if the service state changes from in-s ervice to
MTC/FE, then stable calls are unaffected.