555-233-119
1308
Issue 5 October 2002
— Call Activity States
In addition to the service and pending state, the state of a B-channel
also reflects its call activity. If a call is connected over the B-channel,
then the state of the trunk will reflect the “active” call state, for
example, “in-service/active.” If there is no call on the B-channel,
then the trunk will reflect the “idle” call state, for example,
“OOS/FE-idle.”
The following diagram of the DS1 ISDN Trunk service states shows the
common progression from one service state to another and the event that
caused the change of state.
Figure 37.
Common Progressions in Service States
Craft busyout of B-channel
(TRK-GRP/MBR), or problem
with near en d PI-LINK, DS1-BD,
PI-BD, or port.
long test of the trunk.
Craft busyout of signaling link
busyout link LINK-NO or
transient state for demand
link, or craft
demanded test
completed.
of signaling
Craft release
If D-channel
controlling the
B-channel is
up, send a
message
requesting
transition to
In-Service.
least 90 seconds,
or Remote Level 3
Query failed.
been down for at
D-channel has
Maintenance
Near End
Maintenance
Far End
Pending
In-Service
Maintenance
Far End
Craft release of
B-channel or
clearing of near-end
problem with
DS1-BD, PI-BD,
PI-LINK or port.
Out-of-
Service
Far End
Out-of-
Service
Far End
Pending
In-Service
Out-of-
Service
Near End
Administer
B-channel
as member
of a trunk
group.
If D-channel control-
ling the B-channel is
up, send a message
requesting transition
to In-Service.
Failed to receive
reply from far
end. MTCE will
periodically try
to resend the
message.
Received
acknowledgement
or other
indication from the
far end that
B-channel is in service.
or other indication
from the far end,
that B-channel is
inservice.
acknowledgement
Received
message. [Country
protocol 1]
try to resend the
MTCE will periodically
reply from far end.
Failed to receive
in service.
B-channel in/not
from far end that
Received indication
message. [country
protocol other than 1]
try to resend the
MTCE will periodically
reply from far end.
Failed to receive
In-Service