1 CDMA2000 Packet Data Access Network Evolution September 26, 2005 Jun Wang, Pete Barany, Bibhu Mohanty Qualcomm Inc Notice: Contributors grant free, irrevocable license to 3GPP2 and its Organization 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 portions of the contribution; and at the Organization Partner’s sole discretion to permit others to reproduce in whole or in part such contributions or the resulting Organizational Partner’s standards publication. Contributors 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 contributors to assist 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 the contributors. The contributors specifically reserves the right to amend or modify the material contained herein and nothing herein shall be construed as conferring or offering licenses or rights with respect to any intellectual property of the contributors other than provided in the copyright statement above.

2 Outline Current Architecture Problems with Current Architecture Objectives Proposed New Architecture Proposed Solution Call Flows Transition Plan Conclusion and Further Works

3 Current Packet Data Network Architecture

4 Current User Plane Protocol Stack for Simple IP

5 Current 3GPP2 Solutions PPP at the PDSN and the MS/AT PPP performs following functions –Packet Data Service Authentication –IP address allocation –IP header compression negotiation and configuration –Protocol identification –HDLC-like Framing for higher layer packets –Error detection for higher layer packets For Access Network Authentication: –1x: Using IS-41 authentication procedures –HRPD: Rely on PPP CHAP between the AT and AN

6 Problems with the Current Architecture Network Complexity –Need multiple interfaces –Require too many 3GPP2 specific entities –Handoff Complexity (Inter-PDSN, Inter PCF, Inter BSC handoff) Substantial Latency for both signaling and bearer –Call setup Latency –Bearer Transmission Latency HDLC-like Framing is not efficient –Processing Intensive –Unpredictable Increase in Bandwidth Can only have one Header Compression (HC) Instance because of single PPP restriction Excess coupling between RAN and PDSN –Packet Dropping in the RAN affects HC state in the PDSN –Need Flow Control Mechanism between the RAN and the PDSN Centralized Architecture limits Scalability –PDSN needs to maintain per-user states for all terminals in dormancy Hard to add new features/services

7 Objectives (1) Simplify the network architecture –Streamline network entities and interfaces –Simplify handoff procedures Universal access –Common Mobility management across several access networks –Cdma2000/WCDMA/WLAN… Common user experience across different networks Interworking between the new network and legacy network Smooth Transition to the new architecture Ability of rapid introduction of new services Reduce the cost of network/operations Backward Compatibility –Backward Compatibility to the legacy network –Backward Compatibility to the legacy terminal

8 Objectives (2) Improve data transmission/ bandwidth efficiency Seamless Handoff Provide “Always On” capability while minimizing the state maintenance Reduce Signaling latency/chattiness Reduce media transmission delay Improve network security Enhance packet data service provisioning

9 Proposed New Architecture

10 Functions of Access Network Entities (1) Local Mobility Home Agent (LMHA) Functions: –Controlling/ Delegating IP address to the MS/AT –Mobility Management by acting as a MIP Home Agent for the MS/AT Controlling Access Point (CAP) includes two entities: –Access Gateway (AGW) –Radio Resource Management (RRM) Access Gateway (AGW) Functions: –First-Hop Router for the MS/AT –Authentication Functions –RADIUS Client (for authentication) –Mobility Management by sending Binding Updates to the LMHA on behalf of the MS/AT –DHCP Relay/Server –Some other 3GPP2 specific PDSN functions (Hot lining?)

11 Functions of Access Network Entities (2) Radio Resource Management (RRM) Functions: –Common Resource Management –Dedicated Resource Management –Radio Session Management –Maintain the MS/AT Session State –Session Transfer –Radio Link Management: –Connection Setup and Release –Handoff –QoS Support –Header Compression –Accounting Functions –RADIUS Client (for accounting) –TFT –Ingress address filtering Base Transceiver System (BTS) Functions: –IP Terminating Point –Common Resource Management –Dedicated Resource Management –Implementing OTA Protocol Stack (along with RRM)

12 Interfaces Interface between LMHA and CAP: –Use IETF Standard Protocol (e.g., MIP) Interface between CAP and CAP: –3GPP2 standard interface

13 Proposed Solution Key Concepts –Remove HDLC-like Framing and use Segment Based Framing in the CAP –Authentication: –Use IETF protocol, e.g., EAP –IP Address Assignment: –Use IETF protocol, e.g., DHCP –Header Compression Negotiation: –Using OTA signaling –Maintain the packet data session state in the CAP –Decoupling Handoff from Session Transfer –Current 3GPP2 specific PDSN/PCF functions integrated to the CAP –CAP Interworks with legacy RANs via existing 3GPP2 interfaces

14 Proposed User Plane Protocol Stack for Simple IP

15 Authentication Potential EAP Methods: –Possible Requirements: –Need to provide mutual authentication –Need to provide User Identity Privacy –Need to derive session keys for OTA protection –Candidate Solutions: –EAP-AKA –EAP-TLS-PSK (does not provide user identity privacy) –EAP-TTLS EAP Transport: –EAP over PANA, or –EAP over cdma2000

16 Call Flows for Evolved Architecture (1) (for Simple IPv6 or Mobile IPv6 MS)

17 Call Flows for Evolved Architecture (2) (for Simple IPv4 MS)

18 Call Flows for Evolved Architecture (3) (for MIP4 MS)

19 EAP over PANA Using EAP-AKA as Authentication Method If EAP Response Messages are not piggybacked on PANA-Start-Answer Messages and PANA-Auth-Answer messages, then six more messages are required

20 EAP over cdma2000 Link Layer Using EAP-AKA as Authentication Method

21 Packet Headers (MS/AT Simple IP)

22 Packet Headers (MS/AT MIPv6)

23 Packet Headers (MS/AT MIPv4)

24 Advantages of the Proposal Simplify the architecture More effective packet dropping in the CAP –CAP can drop packets prior to applying compression –Take advantage of better and more up-to-date air link information Better integration between IP header compression algorithms and the CDMA2000 air interface error and timing recovery Simpler CAP-LMHA interface –Air interface changes do not affect LMHA, so no development impact of air interface enhancements –No tight coupling for signaling such as flow control –LMHA becomes a general purpose router => cost effective Faster introduction of new services Easier for interworking between different technologies Simplify the Handoff procedures

25 Proposed Evolution Path Begin with PPP in HDLC-like framing currently deployed Make PDSN and RAN QoS aware to identify QoS flows Allow RAN to negotiate, configure and implement IP header compression and allow PDSN to send IP traffic without PPP for Auxiliary SI (SO67 Support) PPP Free in RAN (CAP) and introduce LMHA as a general IP Router –Allow CAP to configure the IP addresses and other IP attributes –Allow CAP to perform authentication –Move other 3GPP2 specific functions to the CAP –CAP Supports both CAP-CAP interface and CAP-AN interface Support PPP in HDLC-like framing at the CAP for legacy MS Completely drop support for PPP in HDLC-like framing when there no legacy MS in the network We are here (Mid term architecture)

26 Conclusions Evolved Architecture will: –Reduce network complexity by reducing the number of interfaces and network entities –Improve performance by reducing the signaling and bearer latency –Speed up deployment of new services/features by leveraging the existing 3GPP2 and IETF protocols and minimizing 3GPP2 specific network entities –Improve bandwidth efficiency and reduce processing overhead by eliminating HDLC-like framing –Enable multiple header compression channels by eliminating the PPP –Enhance Scalability by adopting a distributed architecture

27 Recommendations The Group Should Start Work on Evolved New Architecture ASAP The PPP Free Work Item Should Apply to the Evolved New Architecture as well Furthermore, Any New Features/Capabilities should be able to work with current architecture and New Evolved Architecture