5-40 Call control procedures
297-2521-106 Standard 23.01 March 2001
Figure 5-22
B-channel glare, BCHGLARE = YIELD
Network User
SETUP (CR = A)
Network selects a PRI trunk
on which to terminate
GLARE
Reselect/route advance
BCHGLARE = YIELD, so network
backs down and lets CR = A
.
.
.
Normal call setup on
call reference A
continue with normal call setup
B-channel lockout
One end of the connection may not receive the expected message before
timer T308 or the DMS-250 switch lockout timer expires. The following
occurs in this case.
User-initiated call clearing
If the DMS-250 switch internal lockout timer expires before a REL COM
message is received, the network puts the trunk member in the lockout state.
If the REL COM message is received before timer T308 expires, the trunk
member is returned to idle from the lockout state.
If timer T308 expires before a REL COM message is received and after the
lockout timer has expired, a second REL message is sent and timer T308 is
restarted. If it expires a second time, the trunk member remains in the
lockout state until restart procedures are invoked on the PRI; otherwise, the
PRI trunk member is returned to idle from lockout, as shown in Figure 5-23.
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