Universal Mobile Telecommunications System (UMTS); LTE; 3GPP Evolved Packet System (EPS); Optimized handover procedures and protocols between E-UTRAN access and cdma2000 HRPD Access; Stage 3 (V12.3.0; 3GPP TS 29.276 version 12.3.0 Release 12)
The present document specifies the stage 3 of the Evolved Packet System S101and S121 reference points between the MME and the HRPD Access Network. The S101 interface supports procedures for Pre-Registration@ Session Maintenance and Active handoffs between E-UTRAN and HRPD networks. The S121 interface supports procedures for RIM information exchange between the MME and the HRPD Access Network. It also specifies the S103 interface between the Serving GW and HSGW. This User Plane interface is used to forward DL data to minimize packet losses in mobility from E-UTRAN to HRPD. Signalling procedures on the S101 interface are used to set up tunnels on the S103 interface.