This European Telecommunication Standard (ETS) specifies the stage 1 d escription of the enhanced Multi-Level Precedence and Pre-emption Serv ice (eMLPP). This service has two parts: precedence and pre-emption. P recedence involves assigning a priority level to a call in combination with fast call set-up. Pre-emption involves the seizing of resources, which are in use by a call of a lower precedence, by a higher level p recedence call in the absence of idle resources. Pre-emption can also involve the disconnection of an on-going call of lower precedence to a ccept an incoming call of higher precedence. The eMLPP service is provided as a network operator s option to a doma in of a network. The domain can be the whole network or a subset of th e network. The eMLPP service applies to all network resources in the d omain that is in common use. The eMLPP service is applicable to all mo bile stations in the domain with all or some mobile stations having a respective subscription assigning precedence according to the eMLPP se rvice. eMLPP is a supplementary service and shall be provided to a subscriber for all basic services subscribed to and for which eMLPP applies. NOTE:It is under study whether normal GSM phase 2 mobile stations wil l be able to be used for this service. The service is described from the service subscriber s and user s poin t of view, in particular: -the procedure for normal operation with successful outcome; -the action to be taken in exceptional circumstances; -the interaction with other GSM services and features. This ETS does not deal with the Man-Machine Interface (MMI) requiremen ts, but makes reference to the appropriate Global System for Mobile co mmunications (GSM) specifications. This ETS is applicable to telese vices 1x and 6x and to all bearer ser vices used in a mobile network according to the digital cellular telec ommunications system GSM if eMLPP is provided. Any interaction with ot her services and/or networks not dealt with in sections 8 or 9 are out side the scope of this ETS.
