Layer 2 Mobility for Real Time Packet Data Service in All IP Network

1. ALLIP-20000717-036 Layer 2 Mobility for Real Time Packet Data Service in All IP Network 3GPP2 All IP Ad Hoc Boulder, CO July 17~19, 2000 Jae-Young Ahn , Kyung-Sik Kim, Sang-Ho Choi Phone : + 82-42-860-3817 E-mail : jyahn@nice.etri.re.kr

2. Background • Motivation • In current 3G cdma2000 Packet Data Service Reference Model(PN-4286), Data Link Layer(PPP or HDLC) should be reestablished in case of changing serving PDSN(Mobile-IP FA) • It results serious degradation or interruption of service • TSG-P already suggested the need of simple link layer protocol with the following properties:(P00 20000605-010, Qualcomm) • Simplicity in protocol and with minimal state • Improved data transparency (minimize byte escaping, bit stuffing, etc.) • Low header overhead on the transport • QoS support • Negotiation of compression (header and/or payload) • Protocol should be extensible • As long as 3GPP2 All IP is highly related to PN-4286, All IP AdHoc is also required to investigate the feasibility of new link layer protocol improving L2 mobility not in PN-4286, but in All IP Network

3. L2 Mobility in All IP MM domain • PS domain in All IP Network experiences more serious problems on L2 Mobility because of temporal attribute of multimedia service • Serious burst data loss in case of time-sensitive application(e.g. packetized Video or Voice) • Resource waste due to retransmission and large buffer due to congestionIn case of Best-effort Application (e.g. simple data ) • No Contribution about Layer 2 (L2) mobility in All IP AdHoc • L3 Mobility could be deleted or restructured because of its potential redundancy between L2 and L7 mobility • L2 is becoming a bottleneck in view of handoff performance • Focusing on L2 Mobility concerned with All-IP Requirements • Use of PPP in All IP network protocol based on current 3GPP2 All IP NAM is to be problematic along with the progress of All IP standardization • Specially unsatisfied results on Editor’s Accepted(Revised) Requirement Items in case of handoff (e.g. No interruption of service , etc.)

4. Possible types of MS in All IP Network • Assume that there are: • Type 0 MS • 2G cdma MS • Type I MS • 3G cdma2000 MS • CS Voice and Image • PS Packet Multimedia Data( Packetized voice, image and data) • Type II MS • Pure All IP Multimedia MS (Wireless SIP or H.323 VoIP) • PS Multimedia data(Packetized Voice, Image and Data) => RTP/UDP/IP

5. L2 Mobility of MS Type I • Use of PPP for link layer between MS and PDSN • In hand-off between PDSNs, require PPP reestablishment • Real time packet data => Intolerable data loss • In Current cdma2000 System for packet data => No solution • Best-effort Application => Needs retransmission and sufficient buffer • Complex Header Compression due to PPP frame format and Various RLP Instances • Evaluation • Insufficient capacity for Real-time Multimedia services • Only usable for simple packet data service • Only one detour depending on PDSN coverage planing • PDSN capacity is to be the major hurdle • Depending on operator’s policy

6. L2 Mobility for MS Type II • Upgrade of link layer protocol means a room for upgrading L2 Mobility for All IP • Use of PPP for All IP Network means the easy migration from 3G legacy network but the same problems are remained • Improve of L2 Mobility by using non-PPP protocol is required to support real-time multimedia service • Advantage • Possible smooth and fast handoff for real time packet data • Disadvantage • It may need the modification of the air interface protocols • It may need authentication procedure instead of CHAP extension • It may need modification of TR45.6 functions • Needs the increased cost for evolution

7. Smooth Handoff Aspect on Type II MSs • Using PPP • Need of MS which can control multiple PPP session for the support of function similar to soft handoff • Need of the solution for complex header compression • Using non-PPP • Need of new protocol for Type II MS and network entities • Need of new solution for loose header compression

8. Conclusion • Justification • upgrading L2 mobility results improvement of handoff performance consistent with Lucent contribution (ALLIP-20000717-020) “requirement sec. 6.1.9.Mobility Management” • (e.g. Access Network Mobility with no service interruption) • In order to support real-time service in All IP, L2 Mobility protocol should me improved as well as L7 and L3 Mobility management • L3 MM functionality can be controlled in conjunction L2 upgrade, since L3 MM has potential redundancy in IP MM domain • Conditions for further improvement • Handoff performance of the new protocol for L2 mobility should be enough to support QoS requirement for real time service including packetized video and voice • Reliability for real time packet data is to be improved as well

9. Suggestions • CRs to 3GPP2 All IP Ad Hoc Requirement v0.4.0 • In section 6.2.1 , add item b)” The all-IP network IP MM domain should support link layer handoff for real-time multimedia, in a way of maximizing handoff performance • In section 6.3.4 , correct item d)”The All IP Network IP Multimedia domain shall support hard handoff between two RANs of the same technology, by means of L2 mobility • In section 6.3.4 , add item e)” Handoff performance of L2 mobility should be enough to support QoS requirement for real time service including packetized video and voice • Suggestions on 3GPP2 All IP Ad Hoc NAM • NAM is to be prepared in a way of supporting improved L2 mobility (Possibly in regarding of restructuring the duplication of L2/L3 Mobility Management) for real time packet data service