1. 1 MAPSUP in eHRPD: Data forwarding Tunnel Sources: ZTE Contact: Bi YiFeng (bi,yifeng@zte.com.cn)bi,yifeng@zte.com.cn Rajesh Bhalla (rabhalla@zteusa.com)rabhalla@zteusa.com ABSTRACT: This contribution is used to discuss the “Data forwarding Tunnel” during optimized handover when MAPSUP is used. Recommendation: Review and approve The contributing companies grant a free, irrevocable license to 3GPP2 and its Organizational Partners to incorporate text or other copyrightable material contained in the contribution and any modifications thereof in the creation of 3GPP2 publications; to copyright and sell in Organizational Partner's name any Organizational Partner's standards publication even though it may include all or portions of this contribution; and at the Organizational Partner's sole discretion to permit others to reproduce in whole or in part such contribution or the resulting Organizational Partner's standards publication. The contributing companies are also willing to grant licenses under such contributor copyrights to third parties on reasonable, non-discriminatory terms and conditions for purpose of practicing an Organizational Partner’s standard which incorporates this contribution. This document has been prepared by the contributing companies to assist in the development of specifications by 3GPP2. It is proposed to the Committee as a basis for discussion and is not to be construed as a binding proposal on contributors. The contributing companies specifically reserve the right to amend or modify the material contained herein and to any intellectual property of contributors other than provided in the copyright statement above.

2. 2 Problem Statement In the present protocol, only the APN is used to indicate a PDN in the S101 signaling during optimized handover from 3GPP to eHRPD So how to establish multiple S103 tunnels to a MAPSUP APN during a optimized handover procedure needs to be considered.

3. 3 Analysis Principles made in 3GPP: The S103 reference point shall support the following requirements (refer to 3GPP TS 23.402 Release 9): The S103 interface shall support the ability to tunnel traffic on a per- UE, per-PDN basis The S103 interface shall support Generic Routing Encapsulation (GRE) including the Key Field extension. The Key field value of each GRE packet header uniquely identifies the PDN connectivity that the GRE packet payload is associated with. From the requirements, we can find that the S103 tunnel should be per PDN connection. And in the present protocol, only the APN is used to indicate a PDN in the S101 signaling, so how to establish multiple S103 tunnels to a MAPSUP APN during a optimized handover procedure remains a problem.

4. 4 Analysis (Continued) Figure 3 is the S103 tunnel establishment procedure using the S101, A10/A11 and S1 signaling. In the present protocol (3GPP2 Rev 0, 3GPP R8), steps 1-4 contain APN which is used to identify a PDN (also a PDN connection). When the MAPSUP is used, there will be more than one PDN connections to a single APN, so only the APN cannot identify a PDN connection. If only the APN is contained in steps 1-4 as above, there will be only one S103 created. This cannot fulfill the 3GPP requirement. Figure 3

5. 5 Solutions Option 1: Use the LBI in the S101, A10/A11 and S1 signaling. After the HSGW receives the APN and LBI, the HSGW generates one HSGW GRE key (S103 GRE key) to one pair of APN+LBI. That means if the there are “n” LBIs to a APN, the HSGW will generate “n” HSGW GRE Keys and then there will be n S103 tunnels established to that APN. Figure 4 The HSGW generates HSGW GRE keys per “APN+LBI”.

6. 6 Solutions (Continued) Additional description for Option 1: –The HSGW generates the HSGW GRE key (S103 GRE key) only based on APN+LBI. –The S-GW matches the packet data to the S103 tunnel based one the APN+LBI. –After the HSGW receives the forwarding data, it matches the packet data to the right PDN connection based on the Packet Filter/TFT. –Although the HSGW cannot parse the LBI, it can generates different HSGW GRE keys based on the different LBI. This can ensure multiple S103 tunnels will be generated to multiple PDN connections under a single APN.

7. 7 Solutions (2nd Continued) Option 2: Use a number in the S101, A10/A11 and S1 signaling for every APN, the number(m) can indicate how many PDN connections that have been established in EPS system to that APN, after the HSGW receives the APN and the number(m), the HSGW can generate “m” HSGW GRE keys (S103 GRE keys) to that APN. That means if the there are “m” PDN connections to that APN, the HSGW will generate “m” HSGW GRE Keys and then there will be “m” S103 tunnels established to that APN. Figure 4 The HSGW generates m HSGW GRE keys to that APN.

8. 8 Solutions (3th Continued) Other options?

9. 9 Proposal To use option 1.

10. 10 Thanks!