Download Shall we apply paging technologies to proxy mobile IPv6?

in Proceedings of the 3rd international workshop on Mobility in the evolving internet
architecture, Seattle, WA, USA, 2008, pp. 37-42
Shall we apply paging technologies
to proxy mobile IPv6?
J.-H. Lee,
T.-M. Chung,
S. Pack, and
S. Gundavelli
1
Outline
• Introduction
• Preliminaries
– Proxy Mobile IPv6
– Paging Mechanism
• Paging Extension for PMIPv6
• Performance Evaluation
• Conclusions and Future Work
2
Introduction
• The Host-Based Mobility protocol depends on the
mobility stack installed in a mobile host (MH).
– which typically operates in a limited capacity
• maintaining binding information has a strong influence on the limited
resource.
• Proxy Mobile IPv6 (PMIPv6) supports network-based
mobility for the MH.
– the MH does not need to install the mobility stack into its
protocol stack.
• handoff across different networks without its own mobility signaling cost
3
Introduction (cont.)
• Drawbacks of PMIPv6
– all mobility signaling is controlled through the mobility entities
– data traffic of MH must be managed by the mobility entities
– This network-based mobility architecture
• not only lacks the network resource,
• but also limits the scalability in support of very large numbers of MHs
• we propose a paging extension scheme
– to minimize the signaling overhead and optimize mobility
management cost in PMIPv6.
4
Outline
• Introduction
• Preliminaries
– Proxy Mobile IPv6
– Paging Mechanism
• Paging Extension for PMIPv6
• Performance Evaluation
• Conclusions and Future Work
5
Proxy Mobile IPv6 (PMIPv6)
• Mobile IPv6 requires client functionality in the IPv6 stack
of a mobile node.
– Host-based
• Network-based mobility is another approach to solving
the IP mobility challenge.
• Per-MN-Prefix model
– an addressing model where there is a unique network prefix or
prefixes assigned for each node.
S. Gundavelli, K. Leung, V. Devarapalli, K. Chowdhury, and B. Patil, "Proxy Mobile IPv6," IETF, RFC 5213, 2008.
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• Local Mobility Anchor (LMA)
– has the functional capabilities of a MIPv6 home agent as with
the additional capabilities
– the topological anchor point for the MN’s “home network”
prefix(es) in a PMIPv6 domain
• Mobile Access Gateway (MAG)
– a function on an access router
– tracks the MN’s movements
– manages the mobility signaling on behalf of an MN
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Initiation
wide area
network
Proxy Binding Ack.:
with a home prefix
for the MN
(e.g., 1400:0112::1/64)
Proxy Binding Update:
with MN-ID and
the address of MAG1
correspondent node
home
domain
LMA
home domain
3
(e.g., 1400:0112::0/40)
2
MAG2
MAG1
(e.g., proxy-CoA1)
4
AP1
1) Unicast Router Advertisement
2) Configure “home address”
(e.g., 1400:0112::1::30)
1
AP2
L2 access authentication
with MN-ID
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CommunicationCommunicate with the MN
using the MN’s “home address”
(1400:0112::1::30::MN_MAC)
Downlink :
LMA tunnels packets that
destined to the MN’s
“home address”
to Proxy-CoA1
Uplink:
MAG1 tunnels packets from
the MN to the LMA
wide area
network
correspondent node
home
domain
LMA
home domain
(e.g., 1400:0112::0/40)
MAG1
AP1
MAG2
AP2
9
Handover within the Home Domain
wide area
network
Proxy Binding Ack.:
with the same home prefix
for the MN
(i.e., 1400:0112::1/64)
Proxy Binding Update:
with MN-ID and
the address of MAG2
correspondent node
home
domain
LMA
home domain
3
(e.g., 1400:0112::0/40)
2
MAG2
MAG1
(e.g., proxy-CoA2)
AP1
1
4AP2
1) Unicast Router Advertisement
2) use the same “home address”
L2 access
(e.g., 1400:0112::1::30)
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authentication
Communication-2
Communicate with the MN
using the MN’s “home address”
(1400:0112::1::30::MN_MAC)
wide area
network
correspondent node
home
domain
LMA
home domain
(e.g., 1400:0112::0/40)
MAG1
AP1
MAG2
AP2
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• Network traffic bottleneck at the LMA while it tries to
support a large number of MHs
– all registration messages generated by MAGs,
– data traffic generated by MHs, and
– data traffic destined for MHs
12
Paging Mechanism
• operates on a set of neighboring networks which
constitutes a paging area.
– active mode
• the mobility entity, i.e., home agent or LMA recognizes the exact location
of the MH
– idle mode
• the MH hands off across different networks in a paging area without the
registration procedure resulting in need for paging
• achieve a reduction in signaling loads occurred by MHs in
the idle mode
• a battery consumption at the MH is reduced significantly
13
paging mechanisms for Mobile IPv4 in [3]
• Home Agent paging – the paging initiator is the home
agent
– simple  required only at the home agent and mobile host
– flexible  different update and paging algorithms may be
implemented in the home agent and mobile hosts.
– reduced efficiency  home agents may be located some
distance from the mobile hosts
– poor scalability
– decreasing reliability  the failure of a home agent or paging
process in a home agent would render all the mobile hosts it
serves unreachable
– deployment  the paging information could be considered
confidential and may not be available
[3] R. Ramjee et al. IP Paging Service for Mobile Hosts. In Proc. of ACM SIGMOBILE, pages 332–345, July 2001.
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• Foreign Agent paging – the previous foreign agent is the
paging initiator
– simple  requiring changes to foreign agents and mobile hosts.
– scalability  the processing load of paging is distributed among
the different foreign agents
– efficient and deployable  the confidentiality issues of Home
Agent paging are avoided
– somewhat flexible  different update and paging algorithms
can be implemented in the mobile hosts and foreign agents
– will not work with the mobile host co-located CoA option of
Mobile IP
– reliability  the failure of the previous foreign agent could
result in the mobile host being unreachable indefinitely
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• Domain paging – paging initiator selected
dynamically
– load balancing for performance
– fail-over for reliability
– reliability  a completely distributed approach, retaining the
scalability and efficiency
– confidentiality issues of Home Agent paging are avoided
– truly localized  no updates to the home agent due to paging
– works both with the co-located care-of option of Mobile IP as
well as the network-based foreign agent option.
– additional functionality in the routers
– not as simple to implement nor as easy to deploy
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paging performance study [6]
• the paging size is the most important unit for acquiring
the effect of IP paging.
• IP paging shows its ability only when the number of cells
per network is small.
• However, we argue that this interpretation of paging in
IP-based mobility protocols has to be examined under
various performance parameters, not only by the cell size.
[6] J. Kempf and P. Mutaf. IP Paging Considered Unnecessary: Mobile IPv6 and IP Paging for Dormant Mode Location
Update in Macrocellular and Hotspot Networks. In Proc. of IEEE WCNC, pages 1032–1036, March 2003.
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Outline
•
•
•
•
•
Introduction
Preliminaries
Paging Extension for PMIPv6
Performance Evaluation
Conclusions and Future Work
18
Design considerations
• Support for unmodified mobile hosts
– the previous paging mechanisms proposed for HBM protocols
require paging response messages sent from the MH
• Reduction in mobility signaling cost
– signaling converging to the LMA
• increases the network unavailability probability
• decreases the scalability in support of very large numbers of MHs
• Avoidance of paging processing at a single point
– the paging processing would be distributed among the MAGs
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Paging Architecture
• the MAGs in the same paging
area are involved in the same
multicast group
• time-based state
– a lifetime of a currently active
binding for an MH
turns into the idle mode
when the lifetime is expired
– the serving MAG informs other
MAGs located in the same
paging area
• The paging area information is only updated in the LMA when the
MH hands off to a new paging area
20
Paging Message Sequence
Idle Indication?
Idle Indication?
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Outline
•
•
•
•
•
Introduction
Preliminaries
Paging Extension for PMIPv6
Performance Evaluation
Conclusions and Future Work
22
Network Model
• each paging area is consisted of the
same number of cells
• an MAG is located in each cell
– a cell is considered as a subnet
• The number of cells in the L-level
paging area is calculated as follows
23
Mobility Model
• Fluid-flow model
– suitable for MHs having a high mobility and static velocity
• The direction of an MH is distributed uniformly in the
range of (0, 2π)
• The cell and paging area crossing rate:
–
–
–
–
ν  the average velocity of the MH
ρ  the MH’s density
Lc  the cell perimeter
Lp  the paging area perimeter
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Cost Analysis
• the location update for the basic PMIPv6
MAG-LMA
MH-MAG
tunnel
Move out of cell
location update
refreshing
25
• the location update for the PMIPv6 with paging extension
MAG-LMA
MH-MAG
active mode MH 移出cell
location update refreshing
tunnel
incoming/outgoing
session for idle mode MH
Signaling between MAGs
paging when session incoming
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Numerical Results
• it is typically assumed that
the distance between the
MAG and the LMA (tγ) is
larger than the distance
between the MAGs (tβ)
• pα includes CPU processing
time, queuing delay, etc
Size of a cell = 6500 m2  32~130 MHs per cell
[11] X. Zhang, J. Castellanos, and A. Campbell. P-MIP: Paging Extensions for Mobile IP. ACM Mobile Networks and
Applications, 7(2):127–141, March 2002
27
• slow moving MHs stay in the same cell (subnet) for longer periods
than the fast moving MHs.
• the size of paging areas is carefully designed and deployed in
networks.
• such a problem can be absorbed by applying the dynamic paging
algorithm [10]
– the paging area is dynamically allocated based on several performance units
[10] Xie, H., Tabbane, S. and Goodman, D.J. Dynamic Location Area Management and Performance Analysis. In Proc.
of IEEE VTC, pages 536–539, May 1993.
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• the fast moving MHs frequently hand off across the cell
boundary
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• small percentage of MHs operating in the active mode
30
• if there are all MHs operating in the active mode, the
paging extension scheme cannot improve the network
performance
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Outline
•
•
•
•
•
Introduction
Preliminaries
Paging Extension for PMIPv6
Performance Evaluation
Conclusions and Future Work
32
Conclusions
• PMIPv6 follows a centralized mobility management architecture
– poses heavy burden on the LMA and
– causes network traffic bottleneck at the LMA.
• The proposed paging scheme has a decentralized paging
architecture that distributes the paging state among the MAGs
– the processing load of paging MHs is decentralized.
• We have modeled the location update cost
– using layered hexagonal network model and the fluid flow model.
• numerical results confirm that the proposed paging extension
scheme provides significant reduction in the location update cost
• In future, we would like to explore dynamic paging algorithms to
further reduce the signaling load.
33