Abstract: In order to improve the security and reliability of SGSN which is the core equipment of data service in GSM-R, the redundancy mode of SGSN equipment in GSM-R network was analyzed briefly, the technology of SGSN pool was studied in detail, and the working principle, key parameters, redundancy advantages, networking mode and the conditions of integration with existing networkof SGSN pool were explored. The results show that this technology realizes the SGSN pool group working mode, breaks the one-to-one control relationship between the base station controller (BSC) and SGSN, and realizes the intra domain connection routing function from the BSC node to multiple SGSN nodes, and thatSGSN serves large service area in pool group mode, improves the reliability of the core network, and realizes the redundancy backup of SGSN level.

Key words: redundancy, data service, core network, serving GPRS support node(SGSN), GSM for railway(GSM-R)