Nortel DMS-250 - No Response after a CALL PROC Message; Protocol Violations

Call control procedures 5-43
Digital Switching Systems DMS-250 ISDN Reference Manual MWC14 (CSP14)
No response after a CALL PROC message
After receiving a CALL PROC message from the terminating user, if timer
T310 expires before any call progress indication is received from the
terminating user, the DMS-250 switch releases the call and provides
call-not-accepted treatment. Call progress indication is in the form of one of
the following messages: ALERT, CALL PROC, CONN, or REL. The call
control in this event is shown in Figure 5-26.
Figure 5-26
PRI-to-PRI call setup, no response after CALL PROC message
Originating
user
Network
Terminating
user
SETUP
CALL PROC
SETUP
REL
Start T303.
Stop T303.
Start T310.
T303 expires.
Originator is rerouted.
CALL PROC
Protocol violations
If a protocol violation is detected during the termination of a call over a PRI
interface, the originator responds to the network with a REL message
indicating the reason for the protocol violation. Possible protocol violation
cause values include the following:
• information element does not exist
• protocol error unspecified
• message type is nonexistent
• invalid information element contents
• mandatory information element is missing
• message is not compatible with state
If the DMS-250 switch receives a REL or DISC message with any of these
cause values, it reselects or route advances.