IEEE 802.21 MEDIA INDEPENDENT HANDOVER DCN: 21-10-0114-01-srho Title: Comments and Questions for Optimized Single Radio Handover Procedures of WMF Date Submitted: June 2, 2010 Presented at IEEE 802.21 Authors or Source(s): Yoon-Young An, Junghoon Jee, Hongseok Jeon, Changmin Park, Byungjun Ahn (ETRI) Abstract: Comments and Questions for Optimized Single Radio Handover Procedures of WMF

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Optimized Single Radio Handover Key Features

Pre-Registration over L3 tunnel E.g., WiMAX SFF (Signaling Forwarding Function) performs target BS (Base Station) operations while the MS is located in non-WiMAX Access network MAC messages transfer over L3 tunnel Pre-registration toward target WiMAX network IP Core Network Data ASN-GW WiMAX SFF AR Pre-registration through L3 tunnel BS (Target) Serving AP BS (Another Candidate)

Review of Detailed Procedures - WiMAX IWK case

Overall Steps Note: Figure from DCN 21-10-0068-00-0000 and clarification is marked as blue

Phase-1: SR Target Network Detection and WiMAX SFF Discovery Note: Figure from DCN 21-10-0068-00-0000 and the Information Service query is added by referencing DCN 21-10-0005-00-0000

Comments for Phase 1 Complete network discovery phase is not specified in 3G IWK document SFF Discovery + Information of available access networks, Information about interworking and roaming aspects The DHCP and DNS procedures for “SFF IP address discovery” are not required in case where Information Server provides SFF IP address to MS through MIH_Information_Response as per DCN 21-10-0005-00-0000

Phase-2: SR Handover Session Pre-Registration (1) Current MN/WiMAX State: Idle or Null State Assumption ASN-GW for WiMAX SFF  Pre-registered ASN-GW Pre-registered ASN-GW includes Authenticator MN IP Core Network WiMAX SFF Target BS/ASN-GW Pre-registered ASN-GW Anchored ASN-GW HA Information Server AAA WiFi WiMAX AP Data IKEv2 procedure to setup a secure tunnel Phase2 secure tunnel WIMAX SFF starts to perform BS operation DCD/UCD & BSID Initial Network Entry Procedure (stage3 4.5.1.1) MS-to-Network EAP authentication Process + MS 802.16e registration MS-to-Network EAP authentication process REG_REQ MS_Attachment_Req MS_Attachment_Rsp REG_RSP MS_Attachment_Ack Connections Establishment Data Path Establishment

Phase-2: SR Handover Session Active mode HO Preparation (2) Current WiMAX State : Pseudo Active State Assumption Pre-registered ASN-GW includes Authenticator Apply ASN Anchored Mobility (WiMAX stage3 4.7 ASN Anchored Mobility) MN IP Core Network WiMAX SFF Target BS/ASN-GW Pre-registered ASN-GW Anchored ASN-GW HA Information Server AAA WiFi WiMAX AP MOB_MSHO_Req Active mode HO Preparation Procedure • Successful HO Preparation Phase (stage3 4.7.2.1.2) HO_Req HO_Req This message have target BS’s information Context retrieve If Serving ASN is co-located with the authenticator ASN, no Authenticator ID TLV DP Pre-Reg. HO_Rsp HO_Rsp MOB_BSHO_Rsp HO_Ack HO_Ack MOB_MSHO_Ind • Successful HO Action Phase (stage3 4.7.2.2.2) HO_Cnf HO_Cnf HO_Ack HO_Ack

Comments for Phase 2 Active Mode HO Preparation is triggered by MS MS sends MOB_MSHO_Req message to SFF Does SFF trigger Active Mode HO Preparation to sends MOB_BSHO_Req message. At that time, what can Information server do? During Active Mode HO Preparation procedure, suddenly WiFi link is disconnected. WiMAX interface of MS will perform the normal attachment procedure. We have to consider the reactive mode process.

Phase-3: SR Handover Action Assumption Pre-registered ASN-GW includes Authenticator Apply ASN Anchored Mobility (WiMAX stage3 4.7 ASN Anchored Mobility) MN IP Core Network WiMAX SFF Target BS/ASN-GW Pre-registered ASN-GW Anchored ASN-GW HA Information Server AAA WiFi WiMAX AP Network ReEntry DP Pre-Reg. Procedure PBU • Successful HO Action Phase (stage3 4.7.2.2.2) PBA CMAC Key Count Update HO_Complete HO_Complete HO_Ack HO_Ack Current State  Active State Data Path Deregistration Data

Clarifying Questions for Phase 2 and 3(1) Which steps are included for “Pre-Registration”? 1) Initial Network Entry 2) Initial Network Entry + HO Procedures (up to MOB_HO-IND) ASN-GW clarification in the figure of Slide #6? 1) Pre-registered ASN-GW? 2) Anchor ASN-GW? 3) Target ASN-GW (for Target BS)? 4) ASN-GW of WiMAX SFF? Which entity manages the pre-registered contexts? 1) SFF or 2) ASN-GW

Clarifying Questions for Phase 2 and 3(2) WiMAX forum applied ASN anchored mobility(state 3 4.7) to single radio inter-RAT HO procedures Inter-RAT HO needs IP mobility(MIP, PMIP). CSN anchored mobility has IP mobility function.