1. High Mobility를 지원하는 IPv6 기술: IPv6 over WiBro
Internet Computing KUT (
Youn-Hee Han (Chair of TTA PG302 WiBro6 WG)

2. 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

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

4. 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 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

5. 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

6. 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

7. Subnet Model Determination
IEEE Link vs. IPv6 Link (Subnet)
PSS1
PSS2
BS (RAS)
AR (ACR)
PSS3
IEEE Link
IPv6 Link (Subnet)
From the viewpoint of IPv6 ND, BS is just link-level bridge. Unlike IEEE , however, IEEE BS is always acting as the termination point for a communication by using Connection ID instead of MAC address
MAC Header
MAC Header
Bytes: 2 2 6 6 6 2 6
Frame
IEEE 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

8. 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

9. 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

10. 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

11. 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

12. 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

13. 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

14. 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

15. Standardization Trends
IETF
16ng WG – IPv6 over IEEE
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 e (삼성, ETRI, 한국기술교대) WG Item 채택
v6ops WG
IPv6 Deployment Scenario over IEEE e 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 년 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 IEEE 연구, WiBro 망에만 한정된 연구가 아님
IPv6 and Mobility over WiBro

16. 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

17. 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

18. 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

19. 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 ( )
The second NetLMM BoF
65th IETF ( )
The first NetLMM WG
66th,67th,68thIETF ( , , )
The one of very active WGs in IETF meetings
Almost 150~200 persons usually participates in the NetLMM WG
IPv6 and Mobility over WiBro

20. 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

21. 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

22. 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

23. 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

24. 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