Digital Cellular Telecommunications System (Phase 2+); General Packet Radio Service (GPRS); Serving GPRS Support Node (SGSN) - Visitors Location Register (VLR); Gs Interface Layer 3 Specification (GSM 09.18 Version 7.3.0 Release 1998)
The present document specifies or references procedures used on the Serving GPRS Support Node (SGSN) to Visitors Location Register (VLR) interface for interoperability between GSM circuit switched services and GSM packet data services. The present document specifies the layer 3 messages and procedures on the Gs interface to allow coordination between databases and to relay certain messages related to GSM circuit switched services over the GPRS subsystem. The functional split between VLR and SGSN is defined in GSM 03.60. The required procedures between VLR and SGSN are defined in detail in the present document