Section: 7.3.19 RAN Information Relay
Content: The RAN Information Relay message shall be sent on S3 interface between SGSN and MME to transfer the RAN information received by an SGSN from BSS or RNS (or GERAN Iu mode) or by an MME from eNodeB. The procedures are specified in 3GPP TS 23.401[ General Packet Radio Service (GPRS) enhancements for Evolved Universal Terrestrial Radio Access Network (E-UTRAN) access ]  [3]. This message shall also be sent on S16 interface to transfer the RAN information between GERAN or GERAN Iu mode or UTRAN. For handling of protocol errors the RAN Information Relay message is treated as a Response message. Table 7.3.19-1 specifies the presence requirements and conditions of the IEs in the message. Table 7.3.19-1: Information Elements in a RAN Information Relay