14-12 NCAUUI
297-2521-106 Standard 23.01 March 2001
RELease message responds with a Q.931 RELease COMPlete. The system
does not expect a Q.931 DISConnect since there is no B-channel to
disconnect. If the system receives a Q.931 DISConnect, the system honors
the disconnect as a valid indication of TSC clearing.
Network Clearing
The office parameter, MAX_USER_INFO, defines the maximum limit of
the number of ISDN User Information messages that can be transported for
the life of the call. If the number of user information messages transported in
both directions equals MAX_USER_INFO, the DMS-250 sends a Q.931
RELease message with a cause value of 29 “Facility Rejected” to both end
users. MAX_USER_INFO is default to 25; however, it can be up to 65,535
which is the maximum number of User Information messages that can be
transported for the life of a NCAUUI call.
Data Access Point (DAP)
All NCAUUI calls must go to the DAP for translation. The DMS-250 switch
receives all NCAUUI requests in traditional call requests that invoke VNET
or FLEXSAC processing. DAP interaction is necessary to ensure the called
party obtains TSID and TTG from the DAP. The TTG is the TTG of the
terminating PRI agent.
The only request message that the ADF supports is the DAL Call Procedure
Request message. The only response messages that the ADF supports are the
Routing Response, the Suppcode Digit Collection Response, and the Failure
Response messages.
The ADF Routing Response from the DAP receives the supported action
codes 1, 2, 10, 11, 32, 33, 50, 51, 52, and 53. The system rejects all
NCAUUI requests that receive anything other than the above action codes
from the DAP. The DMS-250 sends a Q.931 RELease message with cause
value of 21 “Call Rejected,” location code of “Transit,” and coding standard
of “CCITT” to the user who requests the NCAUUI service.
When the DMS-250 receives a Q.931 SETUP message that indicates
NCAUUI request, the DMS-250 switch formulates and sends an ADF DAL
Request message to the DAP based on existing VNET or FLEXSAC call
processing. Note that the DMS-250 does not trigger the ADF DAL Request
message by the setting of the Bearer Capability IE or the Channel
Identification IE, or the IEs used to initiate NCAUUI. Traditional call
processing for VNET and FLEXSAC calls triggers the initiation of the
message.
There are two conditions that determine whether a call is a VNET. First, the
PRIVDIAL field in table CALLATTR must be set to NCS. Second, the
NSFDFLT field in table TRKGRP must be set to VNET or the NSF IE must
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