. The HSGW ensures converged mobility management between HRPD and LTE networks. The HSGW provides interworking between the HRPD access node and the Packet Data Network Gateway (PGW), a key element of the EPC network. In some network instances, the existing PDSN can be integrated with or upgraded to the HSGW while the existing HA can be integrated with or upgraded to the PGW (or provided as a separate node). The details of several interworking architecture scenarios can be found in [10, .11]. Some key reference points that are required in the interworking architecture are as follows: H1 reference point carries signaling information between a source HSGW (S-HSGW) and a target HSGW (T-HSGW) for optimized inter-HSGW handoff. H2 reference point carries user traffic between a source HSGW (S-HSGW) and a target HSGW (T-HSGW) for optimized inter-HSGW handoff. S101 reference point connects the MME in the 3GPP EPS to the eAN/ePCF in the 3GPP2 eHRPD access network. This reference point provides tunneling of signaling and data between the UE and the target access network via the source/serving access network. S103 reference point connects the Serving Gateway (S-GW) in the 3GPP EPC to the HSGW in the 3GPP2 eHRPD network. Its function is to forward downlink data between the S-GW and the HSGW to minimize packet losses in mobility from E-UTRAN to eHRPD. Pi* reference point connects the HSGW to the 3GPP2 AAA Proxy. Figure 11.9 shows E-UTRAN to eHRPD active mode handoff handover flows for both non-roaming and roaming scenarios. The process starts when E-UTRAN receives CDMA measurement reports from 4 eHRPD is being standardized by 3GPP2 as a method of interworking multiple access networks (eHRPD, E-UTRAN) under a single packet switched core network, SAE/EPC. E2E Network Architecture and Mobility Management hPCRF Operator's IP Services (e.g., IMS, AN-AAA PSS, etc.) Gateway 3GPP AAA HPLMN Server VPLMN S1-MME LTE-Uu 3GPP AAA eNode3 Serving vPCRF Proxy Gateway E-UTRAN/ eHRPD 3GPP2 AAA Proxy H1/H2 A10/A11 eAN/ePCF AN-AAA Proxy A13/A16 HR