Nortel DMS-250 - ISUP-PRI Call Clearing Received Before Alerting; ISUP-PRI Call Clearing before Alerting when Treatment not Applied

MAUUI 19-13
Digital Switching Systems DMS-250 ISDN Reference Manual MWC14 (CSP14)
the MAUUI service. A Q.931 Setup message with UUI is sent to the
terminating PRI agent. The terminating PRI agent responds to this message
with a Q.931 DISConnect message with UUI. If treatment is not applied at
this switch, the UUI is transported to the originating ISUP agent in the
corresponding ISUP REL message.
The following diagram shows the “ISUP to PRI call clearing before alerting
when treatment is not applied” scenario.
Figure 19-13
ISUP-PRI Call Clearing before Alerting when Treatment not Applied
ISUP IAM (UUI)
ISUP REL (UUI)
ISUP RLC
Q.931 Call Proceeding
Q.931 Setup (UUI)
Q.931 DISConnect (UUI)
Q.931 RELease
Q.931 RELease COMPlete
MWC DMS-250
The second scenario is similar to the first scenario except that treatment is
applied at this switch. In this situation, the UUI from the received call
clearing message is copied into an ISUP ACM message. The ISUP ACM
message is used to establish a voice path and is sent to the originating ISUP
agent before the treatment is applied.
The following diagram shows the “ISUP to PRI call clearing before alerting
when treatment is applied” scenario.