INTERNATIONAL TELECOMMUNICATION UNION ITU-T RECOMMENDATION SUMMARY Rec. No. : Q.85.3 Title : Stage 2 description for community of interest supplementary services Study Group : XI - Switching and Signalling Version : New Date of adoption : 1992 Notes : MULTI-LEVEL PRECEDENCE AND PREEMPTION (MLPP) Recommendation Q.85.3 defines the stage 2 for the Multi-Level Precedence and Preemption (MLPP) supplementary service of the integrated service digital network (ISDN) as provided by public telecommunications operators. Stage 2 identifies the functional capabilities and the information flows needed to support the service description. The stage 2 description also identifies user operations not directly associated with a call (see Recommendation I.130). Recommendation Q.85.3 is defined according to the methodology specified in Recommendation Q.65. Recommendation Q.85.3 does not formally describe the relationship between this supplementary service and the basic call but, where possible, this information is included for guidance. In addition, Recommendation Q.85.3 does not specify the requirements where the service is provided to the user via a private ISDN. Recommendation Q.85.3 does not specify the allocation of defined functional entities within a private ISDN; however, it does define which functional entities may be allocated to a private ISDN. Recommendation Q.85.3 does not specify the additional requirements where the service is provided to the user via a telecommunication network that is not an ISDN. Recommendation Q.85.3 is applicable to the stage 3 Recommendations for the ISDN MLPP supplementary service. The term "stage 3" is defined in Recommendation I.130. MLPP service is defined in Recommendation I.255.3. To order the complete text of this Recommendation, please use the Order Form for ITU-T Recommendations. An electronic version of this form is available on ITUDOC (Winword 2.0: UPI=ITU-5265; ASCII: UPI=ITU-2488).