NGMAST2008
Adaptive Context Transfer Scheme
for Fast Handoff in Proxy Mobile IPv6
Sept. 19, 2008
Jaejong Baek, Jooseok Song
{jjb27, jssong}@emerald.yonsei.ac.kr
Department of Computer Science
Yonsei University, Seoul, Korea
Contents
• Introduction
• Related work
 PMIPv6
 Context Transfer Protocol
• Proposed Schemes
 Proactive Handoff scheme
 Reactive Handoff scheme
 Inter Domain handoff scheme
• Performance Evaluatoin
• Conclusion and Future work
• Q&A
2
Introduction(1)
Abstract
• Goal
 Propose a new scheme for reducing the handoff
latency in network-based mobility scenarios based
on Proxy Mobile IPv6
• Ideas
 The integration between PMIPv6 and Context
transfer scheme
 How the context transfer protocol can be achieved
in a PMIPv6 enabled network
• Result
 Reduce handoff latencies based on adaptive
transferring of context information.
3
Introduction(2)
Keywords
• PMIPv6
 IETF : NETLMM working Group
 RFC 5213, Aug, 2008 “Proxy Mobile IPv6”,
S. gundavelli. Ed.
• Context Transfer Protocol
 RFC 4067 : basic and generic protocol
operation between access routers to perform
context transfer
4
Introduction(3)
Mobility concept & definitions
• Terminal mobility
 Ability for a terminal to change network point of
attachment
 Discrete terminal mobility
 Continuous terminal mobility(Handover)
• User mobility
 Defined as the ability for a user to maintain the same
user identity irrespective of terminals and terminal
types
• Service mobility
 Ability for a user to use the particular(subscribed)
service irrespective of the user location and the
terminal that is used for that purpose.
5
Introduction(4)
Handoff types
• Type(a)
 Mobile-controlled handoff
• The MN has the primary control over the handover process
 Network-controlled handoff
• The network has the primary control over the handover process
• Type(b)
 Proactive(Planned) handoff
• A proactive(expected) handover where some signaling can be done in
advance of the MN getting connected to the new AR, e.g., building a
temporary tunnel from the previous AR to the new AR
 Reactive(Unplanned) handoff
• A reactive(unexpected) handover where no signaling is done in
advance of the MN’s move from the previous AR to the new AR
6
Related work(1)
Why Network-based?
• Host-based Mobile IPv4/v6 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
• Battery problem
• Waste of air resource
 No Stable MIPv4/v6 stack executed in Microsoft Windows OS
• No change in MN protocol stack required!
7
Related work(2)
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.
• Only supports Per-MN-Prefix model
 Unique home network prefix(HNP) assigned for each MN.
 The prefix follows the MN.
8
Related work(3)
PMIPv6 Architecture
LMA: Localized Mobility Anchor
MAG: Mobile Access Gateway
IP Tunnel
A IPinIP tunnel LMA and MAG.
Home Network
LMA
MN’s Home Network Prefix (MN-HNP)
CAFE:1:/64
MN’s Home Network (Topological
Anchor Point)
MAG1
Host A
LMA Address (LMAA)
MAG2
LMMD
(Localized Mobility
Management
Domain), PMIPv6
domain
That will be the tunnel entrypoint.
MN’s Home Network Prefix (MN-HNP)
CAFE:2:/64
Proxy Binding Update (PBU)
Host B
MN Home Address (MN-HoA)
MN continues to use it as long as it
roams within a same domain
Control message sent out by MAG to LMA to
register its correct location
Proxy Care of Address (Proxy-CoA)
The address of MAG.
That will be the tunnel end-point.
9
Related work(4)
Context Transfer Protocol
• Goal
 to quickly re-establish context transfer-candidate services without
requiring the MN to explicitly perform all protocol flows for those
services.
 to provide an interoperable solution that supports various Layer 2
radio access technologies
LMA
pMAG
CONTEXT
AR
nMAG
AR
MN
10
Related work(5)
Predictive CTD
• Network controlled, initiated by pAR
• n/pAR : new/previous Access Router
• CTD : CT Data
 Feature context (MN’s previous IP and parameters for nAR)
 which will be used in authentication of MN’s identity
•
CTAR : CT Activate Request, CTDR : CTD Reply
11
Related work(5)
Reactive CTD
• Network controlled, initiated by nAR
• CT-Req message
• CTD
 MN’s previous IP, Feature Context, sequence #, authorization
token
12
Related work(6)
PMIPv6 Signaling Flow(1)
•
PMIPv6
 MN Attachment - Signaling Flow
• PBU : Proxy Binding Update
• PBA : Proxy Binding Ack
• BCE : Binding Cache Entry
• HNP : Home Netwok Prefix
13
Related work(7)
PMIPv6 Signaling Flow(2)
 MN Handoff - Signaling Flow
14
Proposed schemes(1)
Proactive Handoff Scheme
• Authentication information
- MN-ID, shared secret key
• Authorization information
- Lists of authorized services
• Accounting information.
- Usage record of resources
and services
15
Proposed schemes(2)
Reactive Handoff Scheme
16
Proposed schemes(3)
Inter domain handoff scheme
17
Performance evaluation(1)
Analytic modeling
• Cost functions(MIPv6 vs Proposed)
 Location update(CL)
• Existing :   Lh  n(  Lc )
• Proposed :   Ll
 Packet delivery(CP)
• Existing :  nl  s  Dl
• Proposed :  ( ol  s  Dl )  (  nl
 s  Dl )
 Total cost : CT = CL + CP
18
Performance evaluation(2)
Notations
•  : the average number of LMD crossings
• n : the number of CNs.
• Lh : the location update cost to the HA
• Lc : the location update cost to the CN
• Ll : the location update cost to the LMA
• Dl : the packet delivery cost through the LMA
•  nl: the packet arrival rate through the new LMA
•  ol: the packet arrival rate through the old LMA
• s : the average session size
•  = 1.5 : the packet tunnel cost
19
Performance evaluation(1)
Comparison
• Total cost for inter-domain handoff
20
Conclusion and Future Work
• Network-based localized mobility management
 Proactive and reactive schemes.
 adaptive context transfer schemes
• Context transfer protocol reduces the inter and
intra handoff latency by avoiding the re-initiation of
signaling to and from the MN.
• In the future
 we will focus on the detail message structure like how
it will be implemented without modifications on the
current PMIPv6 architecture and present performance
results to assess the effectiveness of this scheme.
21
References
[1] J. Lougney, M. Nakhjiri, C. Perkins, and R. Koodli,“Context Transfer Protocol (CXTP),” RFC 4067, IETF,July 2005,
Tech. Rep.
[2] P. De Silva and H. Sirisena, “A mobility management protocol for IP-based cellular networks,” Wireless
Communications, IEEE [see also IEEE Personal Communications], vol. 9, no. 3, 2002.
[3] S. Gundavelli and K. Leung, “Localized mobility management using proxy mobile IPv6: draft-gundavellinetlmmmip61]
J. Lougney, M. Nakhjiri, C. Perkins, and R. Koodli,
“Context Transfer Protocol (CXTP),” RFC 4067, IETF, July 2005, Tech. Rep.
[2] P. De Silva and H. Sirisena, “A mobility management protocol for IP-based cellular networks,” Wireless
Communications, IEEE [see also IEEE Personal Communications], vol. 9, no. 3, 2002.
[3] S. Gundavelli and K. Leung, “Localized mobility management using proxy mobile IPv6: draft-gundavellinetlmmmip6proxy-11. txt,” IETF draft, February,2008.
[4] J. Kempf et al., “Goals for Network-based Localized Mobility Management (NETLMM),” RFC 4831, April,2007.
[5] H. Duong and S. Dadej, A.and Gordon, “A General Framework for Context Transfer in Mobile IP Networks,”
Vehicular Technology Conference, VTC 2006- Spring. IEEE 63rd, vol. 2, pp. 1017–102 176–88, 2006.
[6] D. Johnson, C. Perkins, and J. Arkko, “Mobility Support in IPv6,” RFC 3775, June, 2004.
[7] C. Politis, K. Chew, N. Akhtar, M. Georgiades, R. Tafazolli, and T. Dagiuklas, “Hybrid multilayer mobility
management with AAA context transfer capabilities for all-IP networks,” Wireless Communications, IEEE [see also
IEEE Personal Communications], vol. 11, no. 4, pp. 76–88, 2004.
[8] M. Georgiades, N. Akhtar, C. Politis, and R. Tafazolli, “Enhancing mobility management protocols to minimise AAA
impact on handoff performance,” Computer Communications, vol. 30, no. 3, pp. 608–618, 2007.
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Q&A
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