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Network Interconnection Interoperability Forum (NIIF)

Issue #0279, SS7 ISUP IAM Precedence Parameter, Update

Provided By
National Communications System (NCS)

To provide priority treatment for 710 wireless calls using the Wireless Priority Service (WPS) (, the SS7 ISUP Precedence parameter may be sent from the originating Mobile Switching Center (MSC) across the PSTN to a terminating MSC. The Precedence parameter is defined as an optional parameter within the SS7 ISUP Initial Address Message (IAM) and is specified in Technical Report 3GPP TR 22.952 V6.3.0 (2005-09), Table A.2. This parameter ensures that a “priority 1” call originated at an MSC will receive the same “priority 1” treatment at a terminating MSC (i.e., queuing and servicing before “priority 2” and lower priority calls). Without transmission of the Precedence parameter, all terminating WPS calls have the same default priority and treatment. According to ANSI T1.113-1995, “American National Standard for Telecommunication Signaling System No. 7 (SS7) – Integrated Service Digital Network (ISDN) User Part,” all switches are required to pass optional parameters and values that they do not understand, such as the Precedence parameter with WPS values. There is a need for the service to be uniform. The NCS has introduced this issue into the ATIS Network Interconnection Interoperability Forum (NIIF) and it is being worked as Issue #0279. NCS intends to enable the sending of the Precedence parameter by the WPS wireless carriers, beginning 31 December 2006. Verification of the capability to handle the Precedence parameter should be completed by 21 August 2006 per ATIS Action Item to allow time for vendors to take corrective action, if necessary, prior to the 31 December 2006 date.

Below, please find a link to the most up to date version of the Issue #0279, SS7 ISUP IAM Precedence Parameter, Update. This version is only available to NIIF members.



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