DEMAPS: A Load-Transition-Based Mobility Management Scheme for
an Efficient Selection of MAP in Mobile IPv6 Networks Tarik Taleb,
Member, IEEE, Abbas Jamalipour, Fellow, IEEE, Yoshiaki Nemoto,
Senior Member, IEEE, and Nei Kato, Senior Member, IEEE 1 IEEE
TRANSACTIONS ON VEHICULAR TECHNOLOGY, VOL. 58, NO. 2, FEBRUARY
2009
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Outline Introduction Related Work DEMAPS Scheme Performance
Evaluation Discussion Concluding Remarks 2
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Introduction Mobile IP (MIP) an important protocol for
accommodating the IP mobility. Hierarchical Mobile IPv6 (HMIPv6)
locally handle handovers by the usage of an entity called mobility
anchor point (MAP). overcome the excessive delay and signaling
involved when handover a more efficient way for mobility management
in IP networks, 3
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HMIPv6 overview 4
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Introduction (contd) For large mobile network, HMIPv6 does not
control traffic among multiple MAPs if the selected MAP is
overloaded, extensive delays are experienced during the routing
process. the traditional distance-based MAP selection scheme The MN
select the MAP that is most distant, provided that its preference
value is not zero (RFC 5380) Some MAPs may overly congested with
packets, whereas others are underutilized. Dynamic Efficient MAP
Selection (DEMAPS) works similar to HMIPv6 when the network is not
overloaded. When the network gets heavy loads, the selection of
MAPs is based on an estimation of MAP load transition using the
exponential moving average method. 5
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Outline Introduction Related Work DEMAPS Scheme Performance
Evaluation Discussion Concluding Remarks 6
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Related Work To reduce handoff-signaling delays in macro
mobility, the central theme in the pioneering studies pertains to
adopting hierarchical management strategies by using local agents
to localize the binding traffic Determining the optimal size of
local networks is one of the most challenging tasks 1.the average
total location update and packet delivery cost 2.mobility patterns,
registration delays, and the CPU processing overhead 7
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some local agents get congested with traffic, whereas other
agents are not efficiently utilized. should be dynamic ex. Dynamic
domain list deliver packets to users via multiple levels of ARs.
leads to long packet delivery delay and congestion of the selected
ARs with redundant traffic. One possible solution to this issue is
to reduce the size of the subnet domains. lead to frequent
interdomain handoffs and, consequently, excessive BU cost. 8
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Related Work (contd) Referring to the mobility pattern
Velocity: if high, register to a MAP at higher level Fixed and
Dynamic consists of high accuracy in estimating the velocity, not
always simple, moving range(area) how the moving range of each MN
can be defined, how the scheme can be applied to MNs that keep
changing their moving areas longer delivery delay the
session-to-mobility ratio (SMR) the ratio of the session arrival
rate to the handover frequency. Small SMR high MAP is selected
9
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Outline Introduction Related Work DEMAPS Scheme Performance
Evaluation Discussion Concluding Remarks 10
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DEMAPS Scheme overview 11 Optimum MAP v dynamic MAP discovery
No change on MN save battery life If OMAP!=Previous MAP, then
inter-domain handover Router Sol. Router Adv. v
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load of a MAP_to_AR link each access point receives MAP option
messages from high- layer MAPs every period of time Define the load
of the ith MAP, as shown in its kth downstream node, at the nth
time slot as M ik [n] C ik : the data processing speed of the ith
MAP on the link to its kth downstream node p ik [n] : the total
number of data packets that are forwarded on the link as a mere
router at the nth time slot q ik [n] : the number of data packets
that are destined to MNs registered with the ith MAP at the nth
time slot W : a weight factor for reflecting the difference in p ik
[n] and q ik [n] 12
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predicting future transitions in a MAPs loads exponential
moving average (EMA) a cut-and-dry approach for analyzing and
predicting performance easy to implement and requires minimal
computational load the EMA value of the ith MAP load with respect
to its kth downstream node at the nth time slot: 13 r is set to
0.9
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E ik [n] < M ik [n] the load of the ith MAP on the link to
its kth downstream node has more tendency to increase [i.e., the
load increase (LI) tendency] E ik [n] > M ik [n] the MAP load on
the same link may likely decrease [i.e., the load decrease (LD)
tendency]. MAP load index tendency RA MAP option 14
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deciding the most appropriate MAPs ARs decide the most
appropriate MAPs for future visiting mobile users Stage 1: When the
network is not overloaded MAPs with loads < = 80% are sorted The
farthest MAP among the sorted MAPs is selected first Stage 2: the
loads of all MAPs > MAPs with LD at higher hierarchy are
preferably selected create large MAP domain for MNs so that their
future handoffs can locally be handled If all MAPs have LI, select
the higher hierarchy MAP with the minimum traffic load 15
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Simulation Setup Use QualNet 4.0 16 for simplicity Over each
inter-MAP link, the rate of the background traffic is randomly
chosen from within 40% to 70% of the link capacity
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two mobility models the random waypoint model the group
mobility model four groups are simulated, with each consisting of
12 or 13 MNs the MN speed is set to [0, 2] m/s, and the pause time
is set to null Compare DEMAPS to HMIPv6 The farthest MAP
(preference!=0) is selected HMIPv6-UP velocity-based MAP selection
scheme in [24] if the velocity > 0.5 m/s, the MN registers with
an upper MAP 17 [24] E. Natalizio, A. Scicchitano, and S. Marano,
Mobility anchor point selection based on user mobility in HMIPv6
integrated with fast handover mechanism, in Proc. IEEE WCNC, New
Orleans, LA, Mar. 2005, pp. 14341439.
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Simulation Results Load transitions 18 HMIPv6HMIPv6-UP DEMAPS
random waypoint group mobility
Slide 19
In HMIPv6, when MNs roam from one AR to another AR, each MN
always selects the same MAP that was previously used The same in
HMIPv6-UP when the MNs mobility pattern does not change. DEMAPS
increase the throughput and reduce the end-to-end delay mostly
attributed to the selection of the most appropriate MAP Higher
throughput MAPs with LD tendencies are preferably selected 19 group
mobility
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aggregate performance both UDP data packets and signaling
packets are plotted the overall bandwidth consumption in DEMAPS is
almost the same as that of HMIPv6 and HMIPv6-UP the additional cost
due to signaling packets is minimal DEMAPS achieves better
distribution of traffic load among the MAPs. Almost no packet drop
mostly due to the transmission of packets over congested links upon
handoff 20 group mobility
Slide 21
binding updates HMIPv6 and HMIPv6-UP reduce the frequency of BU
messages to HAs however, many data packets drop at congested links
the average BU latency for some MNs in the case of HMIPv6 and
HMIPv6-UP is higher than in the case of DEMAPS due to the selection
of heavily loaded MAPs high queuing delays 21
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the effect of changing captures the efficiency of traffic
distribution over the network i is the number of packets that were
processed by the ith link N is the number of inter-MAP links ( = 1
s) represents a good tradeoff between an efficient distribution of
data traffic and a reduced frequency of MAP option packets 22
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small values of consists of the guarantee of high prediction
accuracy of the EMA method 23 =1 s=10 s
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the effect of changing r the system guarantees an efficient
traffic distribution for all the values of r reaches its optimum
when r takes large values (=1) 24
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Discussion DEMAPS neither generates any new signaling packets,
modifies the HMIPv6 protocol itself, nor require any modifications
at the mobile terminals In DEMAPS, the frequency of re-registering
to HA is high Solution: MNs should be given freedom in choosing the
MAPs to which they register If the load of the old MAP is not at a
critical point, the MN can keep registering with it Selecting the
MAP may require some energy at the MN This operation is, however,
performed only upon handoff Solution: implement MAP decision-making
mechanism at ARs the MN could notify the AR of the old MAP via the
RS message 25
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Discussion (contd) The working of DEMAPS can further be
enhanced by anticipating the occurrence of MN handoffs. DEMAPS can
easily be applied with minor modifications to the networks with
mobile routers as used for seamless Internet access in public
transportation and in wireless metropolitan networks 26
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Concluding Remarks DEMAPS significantly improves the
performance of HMIPv6 in large mobile networks a dynamic efficient
technique for selecting the most appropriate MAP for registration
based on an estimation of MAP load transition using the EMA method
easy to implement the additional cost that signaling packets
requires is proven to be minimal Extensive simulation results have
demonstrated that DEMAPS improving the average communication delay,
reducing the number of losses, and making better utilization of the
network resources. 27
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comments DEMAPS is simple but effective Can be applied to Local
Mobility Anchor selection in Proxy Mobile IPv6 Knowing the MAP list
of new AR before handover can improve handover performance In the
case of PMIPv6, the new MAG or the new LMA initiate
handover-performance improving operation 28
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determining the optimal local network size [18] propose an
analytic model based on the average total location update and
packet delivery cost In [19] and [20], the decision is based on
mobility patterns, registration delays, and the CPU processing
overhead that is loaded on the local mobility agents. They are
fixed? Why? dynamic some local agents get congested with traffic,
whereas other agents are not efficiently utilized. the choice of
network hierarchies should be performed in a dynamic manner 29 [18]
J. Xie and I. F. Akyildiz, A distributed dynamic regional location
management scheme for mobile IP, in Proc. IEEE INFOCOM,NewYork,
Jun. 2002, pp. 10691078. [19] M. Woo, Performance analysis of
mobile IP regional registration, IEICE Trans. Commun., vol. E86-B,
no. 2, pp. 472 478, Feb. 2003. [20] S. Pack and Y. Choi, A study on
performance of Hierarchical Mobile IPv6 in IP-based cellular
networks, IEICE Trans. Commun., vol. E87-B, no. 3, pp. 462469, Mar.
2004.
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dynamic local network size selection In [21], a group of ARs
forms a domain. A domain list that indicates the ARs that belong to
the same domain is stored at each AR. MNs that reside in a given
domain maintain that domain list. If an MN changes its point of
attachment to a new AR within a different domain, the node will,
then, update its domain list to that of the new AR, and the new AR
will serve as a MAP for the node. 30 [21] C. W. Pyo, J. Li, and H.
Kameda, A dynamic and distributed domain-based mobility management
method for Mobile IPv6, in Proc. IEEE VTCFall, Orlando, FL, Oct.
2003, pp. 19641968.
Slide 31
In [22], when a mobile host connects to a new subnet via a new
AR, the new AR notifies the new CoA of the host to the previous AR.
The new AR then serves as a new location-management hierarchical
level for the node. 31 [22] W.Ma and Y. Fang, Dynamic hierarchical
mobility management strategy for mobile IP networks, IEEE J. Sel.
Areas Commun., vol. 22, no. 4, pp. 664676, May 2004. dynamic local
network size selection (contd)
Slide 32
[21] [22] both deliver packets to users via multiple levels of
ARs a fact that leads to long packet delivery delay and congestion
of the selected ARs with redundant traffic. One possible solution
to this issue is to reduce the size of the subnet domains. lead to
frequent interdomain handoffs and, consequently, excessive BU cost.
32 dynamic local network size selection (contd)
Slide 33
referring to the mobility pattern In [23], users are classified
based on their velocity. Users receive thresholds from the network
and compare their velocity to those thresholds. If exceed the
thresholds register with higher levels of the MAP hierarchies. the
velocity range for each MAP is fixed does not solve the issues of
traffic distribution among MAPs. in the case where all users have
the same feature of mobility, they end up registering with the same
MAPs. This will intuitively overload the selected MAPs with
traffic, whereas other MAPs remain underutilized. 33
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[25] considered a dynamic setting of the velocity range of each
MAP, depending on the actual velocities of MNs that are currently
serviced by the MAP. A general requirement for schemes based on the
velocity of MNs, consists of high accuracy in estimating the
velocity not always simple, which results, more frequently, in
selecting inappropriate MAPs 34 referring to the mobility pattern
(contd)
Slide 35
In [26], the moving range of an MN is the main factor in the
MAP selection. MNs are assumed to keep track of their moving area.
The lowest MAP that covers the entire moving area is considered the
most appropriate MAP for registration. issues have yet to be solved
how the moving range of each MN can be defined, how the scheme can
be applied to MNs that keep changing their moving areas (? paper)
35 [26] M. H. Liu and C. C. Yang, A multicast extension to HMIPv6
with efficient MAP selection, in Proc. IEEE VTCFall, Dallas, TX,
Sep. 2005, pp. 816820. referring to the mobility pattern
(contd)
Slide 36
In [27], a distributed location management scheme allow an MN
to roam over an area that is covered by a number of MAPs (among
which the farthest MAP is distant from the MN by a threshold of
hops) without triggering regional BUs. Although this operation
achieves load balancing, to some extent, and reduces the BU cost,
it comes at the price of longer delivery delays. paper 36 [27] M.
Bandai and I. Sasase, A load balancing mobility management for
multilevel Hierarchical Mobile IPv6 networks, in Proc. IEEE PIMRC,
Beijing, China, Sep. 2003, pp. 460464. referring to the mobility
pattern (contd)
Slide 37
In [28], a newly defined factor, i.e., the session-to- mobility
ratio (SMR), is used the ratio of the session arrival rate to the
handover frequency. the highest MAP is selected for MNs with small
values of SMR. [29] 37 [28] S. Pack, M. Nam, T. Kwon, and Y. Choi,
An adaptive mobility anchor point selection scheme in Hierarchical
Mobile IPv6 networks, Comput. Commun., vol. 29, no. 16, pp.
30663078, Oct. 2006. referring to the mobility pattern (contd)