High Mobility를 지원하는 IPv6 기술: IPv6 over WiBro Internet Computing Laboratory @ KUT (http://icl.kut.ac.kr) Youn-Hee Han (Chair of TTA PG302 WiBro6 WG)

Table of Contents IPv6 over WiBro Network-based Mobility Conclusions WiBro and IPv6 – Network Architecture Technical Issues Standardization Trends Network-based Mobility Why? Proxy Mobile IPv6 Overview Conclusions IPv6 and Mobility over WiBro

IPv6 Link over WiBro Network Architecture IPv6 & Network Model in WiBro/IEEE 802.16 IPv6 Protocol Suite (Neighbor) PSS IPv6 and Mobility over WiBro

WiBro Network Architecture Point-to-multipoint (PMP) Components PSS: Portable Subscriber Station RAS: Radio Access Station (Omniscient) ACR: Access Control Router Knows about all PSSs and RASs attached to itself Only one ACR at any PSS and RAS A transport connection always exists between PSS and ACR PSS – RAS: IEEE 802.16 MAC connection Connection ID RAS – ACR: GRE Tunnel Traffic is delivered all the way to ACR by using GRE tunnel between RAS and ACR PSS 1 RAS 1 PSS 2 ACR 1 PSS 3 RAS 2 PSS 4 PSS 5 RAS 3 ACR 2 PSS 6 IPv6 and Mobility over WiBro

IPv6 Link over WiBro Network Architecture IP Link An ACR Multiple RASs attached to the ACR Multiple PSSs attached to these RASs ACR is the first hop access router of a PSS. Even from IP perspective, an PSS cannot communicate with another PSS directly. All traffic go through an AR. It implies that an PSS's on-link neighbor is only an AR. PSS 1 IP Link 1 RAS 1 PSS 2 ACR 1 PSS 3 RAS 2 PSS 4 PSS 5 RAS 3 ACR 2 PSS 6 IP Link 2 IPv6 and Mobility over WiBro

Subnet Model Determination Convergence Layer & IPv6 Packet Transport Service Specific Convergence Sublayer (CS) MAC Common Part Sublayer (MAC CPS) Privacy Sublayer Physical Layer (PHY) PHY SAP MAC SAP CS SAP MAC PHY 1) Transformation or mapping of external network data 2) Classifying external network SDUs and associating them to the proper MAC service flow and Connection ID IPv4 Packet Mapping IPv6 Packet header How to efficiently map ? IPv6 and Mobility over WiBro

Subnet Model Determination IEEE 802.16 Link vs. IPv6 Link (Subnet) PSS1 PSS2 BS (RAS) AR (ACR) PSS3 IEEE 802.16 Link IPv6 Link (Subnet) From the viewpoint of IPv6 ND, BS is just link-level bridge. Unlike IEEE 802.11, however, IEEE 802.16 BS is always acting as the termination point for a communication by using Connection ID instead of MAC address 802.16 MAC Header 802.11 MAC Header Bytes: 2 2 6 6 6 2 6 Frame IEEE 802.11 MAC Header Duration Addr 1 Addr 2 Addr 3 Sequence Addr 4 Control ID Control Recipient Addr. Special Addr. Transmitter Addr. FromDS: Original Source Addr., ToDS: Final Destination Addr. IPv6 and Mobility over WiBro

Subnet Model Determination Ethernet CS/Bridging IP CS/GRE Tunnel PSS 1 PSS 1 PSS 2 BS (RAS) AR (ACR) PSS 2 BS (RAS) AR (ACR) PSS 3 PSS 3 Ethernet Header (Source MAC, Destination MAC) Ethernet Header (Source MAC, Destination MAC) IPv6 Header (Source IP, Destination IP) IPv6 Header (Source IP, Destination IP) IPv6 Header (Source IP, Destination IP) GRE Header Ethernet Header (Source MAC, Destination MAC) DATA Payload IPv6 Header (Source IP, Destination IP) DATA Payload IPv6 Header (Source IP, Destination IP) DATA Payload DATA Payload IPv6 and Mobility over WiBro

Subnet Model Determination IPv6 subnet models Shared Prefix Model One (or more) prefixes advertised on the link No native on-link multicast is possible with this method. However ACR can implement proxy mechanism All PSSs send the packets to ACR irrespective of the destination link local scope packets are relayed by ACR IP CS WiMAX has chosen it. But, doesn’t decide yet. PSS 1 IPv6 (Shared Prefix Model) L3 ACR GRE Tunnel L2 RAS Wireless Peer-to-Peer Connection PSS 2 GRE Tunnel L2 RAS [draft-madanapalli-16ng-subnet- model-analysis-00.txt, Sept. 6, 2006] L3 IPv6 (Shared Prefix Model) IPv6 and Mobility over WiBro

Subnet Model Determination IPv6 subnet models Unique Prefix Model the unique prefix per PSS Only an ACR and a PSS belong to an IPv6 link. Many IPv6 functionalities can be implemented without difficulty. If PPP is used between PSS and ACR, most look straightforward. But, PPP CS is not available yet. DAD might be needless Suitable to Cellular-like model PSS 1 IPv6 (Unique Prefix Model) L3 ACR GRE Tunnel L2 RAS Wireless Peer-to-Peer Connection PSS 2 GRE Tunnel L2 RAS [draft-madanapalli-16ng-subnet- model-analysis-00.txt, Sept. 6, 2006] L3 IPv6 (Unique Prefix Model) IPv6 and Mobility over WiBro

IPv6 Neighbor Discovery Service Router (ACR)/Prefix/Parameters Discovery How to deliver Router (ACR) information, On-link Preifx, Link MTU to PSS? Original Unsolicited RA or RS/RA exchange in multicast manner WiMAX/WiBro Approach Unsolicited Unicast RA when PSS attaches to network RS/RA exchange in unicast manner PSSs may use a prefix for address autoconfiguration but not for on-link determination. Valid Lifetime Type Length Prefix Length A Res 1 L I Preferred Lifetime Reserved 2 Prefix PIO (Prefix Information Option) without setting on link flag (L-bit). IPv6 and Mobility over WiBro

IPv6 Neighbor Discovery Service Stateless Address Auto-configuration & DAD Should we support “stateless auto-conf.” in WiBro? If it is needed, how to provide it? How to DAD How to notify ACR’s CS layer of the auto-configured address? Original PSS makes a new address by combining an on-link prefix and its identifier NS/NA Exchange for DAD in multicast manner It takes 1 sec. WiMAX/WiBro Approach Relay DAD Omniscient ACR knows about all PSSs’ addresses attached to itself ACR may relay DAD messages to the destination IPv6 and Mobility over WiBro

IPv6 Neighbor Discovery Service Next-hop Determination & (Neighbor) Address Resolution Next-hop Determination Mapping: Destination IPv6 Address → A Neighbor or A router? Address Resolution Mapping: A Neighbor or A router → Link-layer Address (MAC) Original NS/NA exchange in multicast manner WiMAX/WiBro Approach ACR is the only neighbor for a PSS It’s simple IPv6 and Mobility over WiBro

IPv6 Neighbor Discovery Service Neighbor Unreachability Detection How to know whether a neighbor node is reachable? Original NS/NA exchange in unicast manner WiMAX/WiBro Approach ACR is the only neighbor for a PSS It’s simple We may do this from link-layer event notification without NS/NA exchange. Redirect ACR notifies a PSS of the better next-hop Redirect message delivery in unicast manner No Use IPv6 and Mobility over WiBro

Standardization Trends IETF 16ng WG – IPv6 over IEEE 802.16 2번의 BoF 이후 2006년 7월에 신설 – 매번 100여명 참여 한국 연구자들이 주도적으로 참여 – 삼성전자 의장 2007~2008년: 관련 드래프트들의 RFC화 MIPSHOP WG FMIPv6 over IEEE 802.16e (삼성, ETRI, 한국기술교대) WG Item 채택 v6ops WG IPv6 Deployment Scenario over IEEE 802.16e Link (ETRI, 한국기술교대) WG Item 채택 WiMAX NWG (Network WG) 2006년 IPv6 Subteam의 작업을 통하여 IPv6 및 (Proxy) Mobile IPv6 기술이 최종 문서에 반영 IETF 16ng 의 결과를 WiMAX에서 활용하려고 함 TTA WiBro6 WG (IPv6 PG – PG210) 2005년 10월경 신설 - 2006년 국내 고유 표준 제정, 2007년 현재 Phase II 작업 시작 Phase II 작업은 Proxy Mobile IPv6을 중심으로 작업 IPv6 Forum Korea Mobility WG IPv6 over IEEE802.16 연구, WiBro 망에만 한정된 연구가 아님 IPv6 and Mobility over WiBro

Why Network-based IP Mobility? Host-based Mobile IPv4/v6 (RFC 3344/3775) has not been yet deployed that much. Why host-based MIP is not deployed yet? Too heavy specification to be implemented at a small terminal RFC 3344 (MIPv4): 99 pages RFC 3775 (MIPv6): 165 pages Battery problem Waste of air resource No Stable MIPv4/v6 stack executed in Microsoft Windows OS IPv6 and Mobility over WiBro

Why Network-based IP Mobility? WLAN switch device starts to provide link specific and proprietary solution for IP handover. No change in MN protocol stack required! Layer 3 fast secure roaming The solution works by tunneling traffic from the access point to the WLSM through your Layer 3 core network. No changes to the client devices or the underlying infrastructure are required IPv6 and Mobility over WiBro

Why Network-based IP Mobility? 3GPP, 3GPP2 and WiMAX operators are now showing their STRONG interests for network-based IP mobility solution They are even now deploying their non-standardized network-based IP mobility solution (not Mobile IPv4/v6!). A message from the chair of netlmm WG “3gpp and 3gpp2 have official liaisons to the IETF. 3gpp2 communicated through an official liaison before our session in San Diego that they would like the IETF to produce a standard for proxy MIP. 3gpp maintains a list of what they would like to see from the IETF and they have also communicated their desire to see a standard for PMIP. The IETF does not have an official liaison relationship with the WiMAX forum. They nonetheless sent a message about what they would like to see and some questions. All this information has already been posted here, on the mailing list.” - Phil and Vidya (March 10, 2007) IPv6 and Mobility over WiBro

Why Network-based IP Mobility? Operator’s favoritism Network-based XXX managed by operator itself. However… the opinions are varying… IETF NetLMM WG started to standardize a network-based mobility management protocol. 63th IETF (2005.7) The first NetLMM BoF 64th IETF (2005.11) The second NetLMM BoF 65th IETF (2006.03) The first NetLMM WG 66th,67th,68thIETF (2006.07, 2006.11, 2007.03) The one of very active WGs in IETF meetings Almost 150~200 persons usually participates in the NetLMM WG IPv6 and Mobility over WiBro

Proxy MIPv6 Overview IETF Draft History GOAL S. Gundavelli (CISCO), K. Leung (CISCO), and V. Devarapalli (Azaire Networks), “Proxy Mobile IPv6,” draft-sgundave-mipv6-proxymipv6-00, October 16, 2006. S. Gundavelli (CISCO), K. Leung (CISCO), and V. Devarapalli (Azaire Networks), K. Chowdhury (Starent Networks), “Proxy Mobile IPv6,” draft-sgundave-mipv6-proxymipv6-01, January 5, 2007. S. Gundavelli (CISCO), K. Leung (CISCO), and V. Devarapalli (Azaire Networks), K. Chowdhury (Starent Networks), B. Patil (Nokia), “Proxy Mobile IPv6,” draft-sgundave-mipv6-proxymipv6-02, March 5, 2007. GOAL This protocol is for providing mobility support to any IPv6 host within a restricted and topologically localized portion of the network and without requiring the host to participate in any mobility related signaling. IPv6 and Mobility over WiBro

Network-based Mobility Proxy MIPv6 Overview Host-based vs. Network-based Mobility HA HA Route Update Route Update AR AR Movement Movement Network-based Mobility Host-based Mobility IPv6 and Mobility over WiBro

Proxy MIPv6 Overview Proxy Mobile IPv6 Overview LMA MAG1 MAG2 LMA: Localized Mobility Agent MAG: Mobile Access Gateway IP Tunnel A IPinIP tunnel LMA and MAG. LMA Home Network MN’s Home Network (Topological Anchor Point) MN’s Home Network Prefix (MN-HNP) CAFE:1:/64 MAG1 Host A LMA Address (LMAA) That will be the tunnel entry-point. LMM (Localized Mobility Management) Domain MAG2 MN’s Home Network Prefix (MN-HNP) CAFE:2:/64 Proxy Binding Update (PBU) Control message sent out by MAG to LMA to register its correct location Host B MN Home Address (MN-HoA) MN continues to use it as long as it roams within a same domain Proxy Care of Address (Proxy-CoA) The address of MAG. That will be the tunnel end-point. IPv6 and Mobility over WiBro

Proxy MIPv6 Overview No host stack change for IP mobility Avoiding tunneling overhead over the air Re-use of Mobile IPv6 PMIPv6 is based on Mobile IPv6 [RFC3775]. Mobile IPv6 is a very mature mobility protocol for IPv6. Reuse of Mobile IPv6’s home agent functionality and the messages/format used in mobility signaling. Numerous Mobile IPv6 enhancement can be re-used. PMIPv6 provides solution to a real deployment problem. Home in any place Only supports Per-MN-Prefix model Unique home network prefix assigned for each MN. The prefix follows the MN. IPv6 and Mobility over WiBro

Conclusions IPv6 over WiBro PMIPv6 is New Idea? Wibro 시스템에 최적화된 IPv6 Protocols의 Adaptation 기술 개발 국내 고유 표준 개발 TTA IPv6 PG 산하 WiBro6 표준, IPv6 Forum 표준 국제 표준화 선도 IETF 16ng, WiMAX 등 PMIPv6 is New Idea? Absolutely No! Not new idea, but new trend!. It’s a turn for the better! PMIPv6 is a good example of compromise Until now, long confrontation Telecommunication Operators  Internet Developers and Users PMIP is a good example of compromise It is still RFC 3775 MIP-based one. But, it follows telco’s favoritism! Many SDOs STRONGLY like PMIPv6! PMIPv6 over WiBro IPv6 and Mobility over WiBro