scope:

Introduction

This supplement to American National Standard for Telecommunications - Integrated services digital network (ISDN) - Multi-level precedence and preemption (MLPP) service capability, ANSI T1.619-1992, revises the standard so that the exchange-to-exchange signaling is consistent with ITU-T Recommendations Q.955.3 (1993) and Q.735.3 (1993), which were approved after the publication of ANSI T1.619-1992. The significant changes are in the following areas:

- The use of Cause value #45 with a location code of other than 0110 to indicate preemption without circuit reservation is changed to Cause value #8;

- The use of Cause value #45 with a location code of 0110 to indicate preemption with circuit reservation for reuse is changed to Cause value #9;

- Cause value #46 is in codeset 0 instead of codeset 5;

- The MLPP Service Domain code format is changed from a 7-bit field in the Precedence level information element (for DSS1) and in the Precedence parameter (for SS7) to a 3-octet parameter for both DSS1 and SS7;

- The MLPP Service Domain is prefixed with a 2-octet Network Identity (NI) in the Precedence level information element (for DSS1) and in the Precedence parameter (for SS7).