Architecture for Optimized Handovers between E-UTRAN Access and cdma2000 HRPD Access

S101 Interface

It enables interactions between EPS and HRPD access to allow for pre-registration and handover signalling with the target system.

The S101 interface supports procedures for Pre-Registration, Session Maintenance and Active handovers between E-UTRAN and HRPD networks. This is based on tunnelling over S101 signalling of one technology while the UE is in the other technology. The HRPD air interface messages tunnelled over S101 in E‑UTRAN to HRPD mobility

S101 Protocol Stack

S103 Interface

This User Plane interface is used to forward DL data to minimize packet losses in mobility from E-UTRAN to HRPD.

The S103 interface between the Serving GW and HS‑GW supports the forwarding of DL data during mobility from E-UTRAN to HRPD. Signalling procedures on the S101 interface are used to set up tunnels on the S103 interface.

The S103 supports the following requirements:

• The ability to tunnel traffic on a per-UE, per-PDN basis
• Generic Routing Encapsulation (GRE) RFC 2784 [23] including the Key Field extension RFC 2890 [24]. The Key field value of each GRE packet header uniquely identifies the PDN connectivity that the GRE packet payload is associated with.

 S103 Protocol Stack