Core network integration issues for inter-RAT, inter-SDO mobility (HRPD – WiMax Focus)

1. Core network integration issues for inter-RAT, inter-SDO mobility (HRPD – WiMax Focus) Nortel

2. Harmonizing core network functionality • Most SDOs have some form of an ‘All IP’ core network that incorporates IETF defined functional elements and protocols. • However, each SDO defines their own ‘All IP’ architecture and procedures for how these IETF tools are utilized. Specifically, each SDO defines its own policy framework, AAA framework and mobility management solutions. • Therefore, inter-working between radio access technologies that are defined by different SDOs requires a much broader scope than just mobility management alone. • This contribution highlights the other topics that require consideration (policy, authentication) and it suggests four potential core network solutions.

3. Current releases of other SDOs with dynamic policy control (3GPP2 All-IP, TISPAN R1.0) use off-path signaling All new releases incl. WiMAX specify the ref. point to ASN/visited network to be: bearerless (provide IP flow information per individual AF session) out of band (Diameter-based) off-path (WiMAX also allows parallel option) Bearerless, off-path model is agreed at ITU-T level in Rec. Y.2111 for Policy Control of Next Generation Networks HAAA VAAA v-NASS h-NASS Tx H-PCRF AF V-PCRF U18 e4 Gq’ Ri’ U20 U23 implementation option AF SPDF A-RACF SPDF U15 U16 anchor AGW eBS serving AGW LMA/HA AT Re Ia Ds Di Access Node IP Edge Core Border Nd UE Visited Network Home Network NGN Access Network Provider NGN Connectivity Provider CSN ASN Rx (Tx) Gx/(Ty) Anchor SFA A-PCEF PCRF PCC-R3 Policy Distribution Function AF AAA PCC-based R4 C-PCEF OCS/ OFCS R3 R6 HA SFM BS Serving SFA MS Policy Frameworks WiMAX R1.5 PCC (draft) 3GPP2 evolved network architecture (draft) TISPAN RACS R2 Architecture (draft) • Sources: • WiMAX PCC NWG Rel 1.5 (Unapproved draft, March 2007) • X50-2070514-030r8 Proposed text for X.P00xx-000 UMB Network Specification • Draft ETSI TS 182 019 V0.6.1; TISPAN;Resource and Admission Control Sub-system (RACS) Rel 2.0; (2007-05)

4. AAA Frameworks User Identity Alignment? Authenticator Location? Common AAA server? Authenticator MS BTS GW Proxy AAA Which EAP methods? EAP Method (EAP-TLS, EAP-AKA, EAP-MD5, etc..) Is it EAP in both RATs? EAP EAP Transport AAA Protocol Data Link Encap. UDP / IP RADIUS, DIAMETER or Both? Single or Double EAP?

5. Core network integration for inter-RAT mobility models: • Pair-wise coupling Model: • WiMAX integrated under HRPD architecture • HRPD integrated under WiMAX architecture • IETF-based Common Core • Core elements meet both WiMax and 3GPP2 requirements • 3GPP EPC Model: • WiMAX and HRPD integrated under 3GPP EPC architecture • EPC architecture has specified a number of non-3GPP interfaces and protocols that can be leveraged for inter-working with EUTRAN and between other RATs. • CAN • WiMAX and HRPD both integrated under CAN architecture. • CAN architecture has specified non-3GPP2 interfaces, but has yet to define how policy, authentication and mobility will behave.

6. CSN HA AAA PF Staring Point (non-roaming) WiMAX R3 R6 BTS ASN GW ASN HRPD IMS(CSCF) PCRF Ty A10, A11 HA BTS RNC PDSN AAA

7. CSN HA AAA PF WiMax integrated into HRPD architecture (non-roaming) WiMAX R6 BTS ASN GW ASN R3 R3/PCC Tx or Rx semantics? HRPD Migration to PMIPv6? Tx/Rx? IMS(CSCF) PCRF PF Ty A10, A11 HA BTS RNC PDSN AAA Authentication, credential and identity alignment WiMax aligns to the HRPD core network.

8. CSN HA AAA PF WiMax integrated into HRPD architecture (non-roaming) WiMAX IP Services R3 R6 BTS ASN GW ASN Ty modification? Service Authentication? MIP evolution? Ty HRPD A10, A11 BTS RNC PDSN HRPD aligns to the WiMax core network.

9. WiMax and HRPD integrated into common IETF Core The PCRF / PF supports both Ty and R3/PCC semantics and a common Rx/Tx solution. WiMAX R6 R3 BTS ASN GW ASN IMS(CSCF) PCRF PF IP services HA HRPD Ty AAA A10, A11 BTS RNC PDSN Common IETF Core AAA support different authentication schemes and EAP methods. HA support both HRPD MIPv4 (IS835) and WiMax PMIPv4 (NWGv1.0) IETF core relies on vendors to meet both WiMAX forum and 3GPP2 requirements

10. HRPD and WiMax architecture integrated under EPC (non-roaming) WiMax support PCC R.7. WiMax R1.5 is considering PMIPv6. S7a R6 WiMAX BTS ASN GW AAA ASN IMS(CSCF) PCRF PF S2a PMIPv6 IP services P-GW S2a PMIPv6 HSS/ AAA eHRPD S7a eAN ePDSN Re-use ePDSN framework as is proposed for LTE-HRPD inter-working. AAA AT/eAT AN AAA Tx Ty AN PCRF PDSN HA Legacy HRPD AAA

11. WiMax and HRPD integrated into 3GPP2 CAN architecture R6 WiMAX BTS ASN GW ASN U19a U24a IP services U22a V-AAA H-AAA CMIP 1xEV-DO SRNC aGW HRPD AN H-LMA PMIP V-LMA eBS UMB vPCRF hPCRF CMIP Legacy 1xEV-DO HRPD AN PDSN

12. Summary – Finding a common reference architecture • Service providers will deploy and support a mixture of legacy and emerging technologies. Sometimes more that one emerging technology. • Inter-technology HO requirements will vary – reference architecture should accommodate both different performance requirements • A common reference architecture must be the starting point for the discussion of all technology pairings. The reference architecture must cover: • Mobility • Authentication / Security • Policy • Charging • Fixed / Mobile convergence • Some technology pairings have already settled on a reference architecture • HRPD-LTE (based in EPC) (agreed in 3GPP, decision in 3GPP2 pending) • HRPD-UMB (based in CAN) • WiMax-HRPD (TBD)