Avaya 03-300430 User Manual

Page of 2574
ISDN-TRK (DS1 ISDN Trunk)
Issue 1 June 2005
1449
 
Maintenance/Far-End (MTC/FE)
This state is reached when the far end does not respond after a certain amount of time to 
messages sent over the signaling link for a particular trunk. 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.
Maintenance/Near-End (MTC/NE)
The trunk (B channel) is in this state if the signaling channel (ISDN-LNK) is busied out by 
the system technician. The trunk (B channel) is also temporarily in this state if the system 
technician enters test trunk grp#/mem# long. This command executes the ISDN-PRI 
test call. This test changes the state of the trunk member to MTC/NE for the duration of the 
test unless a call request comes in from the far end. In that case, the test would abort. Note 
that transitions into MTC/NE do not drop stable calls. In this state, the B channel is not 
usable for new incoming or outgoing calls.
Pending States
In addition to one of the previous components, the service state may have a pending 
component, indicating that the switch is waiting for a reply from the far end. These service 
states remain in effect until either a response is received or the allotted waiting time expires.
- Pending-in-Service
The near end is awaiting a far-end response to a B-channel maintenance message 
requesting that a B channel be transitioned to in service. 
The far-end has a certain amount of time to respond to the message. The service state 
will be PINS until either a response is received or the timer expires.
- Pending-Maintenance
This state is supported only by systems using country protocol 1 (including US). The near 
end is awaiting a far-end response to a maintenance message requesting that a B 
channel be transitioned to the maintenance service state. The far-end has a certain 
amount of time to respond to the message. The service state will be PMTC until either a 
response is received or the timer expires.
Call Activity States
The in-service state also has a call activity component.
- Active
A call is connected over the B channel (for example, in service active).
- Idle
There is no call currently on the B channel (for example, in serviced).
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.