This specification defines the stage-2 service description for a General Packet Radio Service (GPRS) on GSM. In analogy with CCITT Recommendations I.130 [1] and with reference to CCITT Recommendations VI.1 Q.65 (Stage 2 of the method for the characterisation of services supported by an ISDN), the second stage of the following three-level structure is derived from a stage 1 service description. Stage 1 is an overall service description, from the service subscriber s and user s standpoints, that views the network as a single entity which provides services to the user. Stage 2 identifies the functional capabilities and information flows needed to support the service described in stage 1. Furthermore, it identifies various possible physical locations for the functional capabilities. The output of Stage 2, which is signalling system independent, is used as an input to Stage 3, the design of signalling system and switching Recommendations. Stage 3 defines the signalling system protocols and switching functions needed to implement the service described in stage 2.