Mobility Management Approaches for Mobile IP Networks
Abstract:
In wireless networks, efficient management of mobility is a crucial issue to support
mobile users. The Mobile Internet Protocol (MIP) has been proposed to support
global mobility in IP networks. Several mobility management strategies have been
proposed which aim reducing the signaling traffic related to the Mobile Terminals
(MTs) registration with the Home Agents (HAs) whenever their Care-of-Addresses
(CoAs) change. They use different Foreign Agents (FAs) and Gateway FAs (GFAs)
hierarchies to concentrate the registration processes. For high-mobility MTs, the
Hierarchical MIP (HMIP) and Dynamic HMIP (DHMIP) strategies localize the
registration in FAs and GFAs, yielding to high-mobility signaling. The Multicast HMIP
strategy limits the registration processes in the GFAs. For high-mobility MTs, it
provides lowest mobility signaling delay compared to the HMIP and DHMIP
approaches. However, it is resource consuming strategy unless for frequent MT
mobility. Hence, we propose an analytic model to evaluate the mean signaling delay
and the mean bandwidth per call according to the type of MT mobility. In our
analysis, the MHMIP outperforms the DHMIP and MIP strategies in almost all the
studied cases. The main contribution of this paper is the analytic model that allows
the mobility management approaches performance evaluation.
MIP:In the MIP protocol, mobile terminals that can change their points of attachment in
different subnets are called mobile hosts (MHs). An MH has a permanent address
(home address) registered in its home network and this IP address remains
unchanged when the user moves from subnet to subnet. This address is used for
identification and routing purpose, which is stored in a home agent (HA). An HA is a
router in a mobile node’s home network, which can intercept and tunnel the packets
for the mobile node and also maintains the current location information for the
mobile node. If an MH roams to a sub network other than the home network, this
sub network is a foreign network for that user. In the current MIP protocol, the MH
can obtain a new IP address from a router [foreign agent
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(FA)] in the visited network or through some external means. An MH needs to
register with the FA or some one-hop router for the routing purpose. The care-ofaddress (CoA) for the MH will change from subnet to subnet. In order to maintain
continuous services while the user is on the move, MIP requires the MH to update its
location to it’s HA whenever it moves to a new subnet so that the HA can intercept
the packets delivered to it and tunnel the packets to the user’s current point of
attachment.
MIP location registration and packet routing:
HMIP:
It is a well-known observation that MNs moving quickly as well as far away from
their respective home domain or correspondent nodes produce significant BU
signaling traffic and will suffer from handoff latency and packet losses when no
extension to the baseline Mobile IP protocol is used. Hierarchical MobileIP (HMIP) is
a localized mobility management proposal that aims to reduce the signaling load due
to user mobility. The mobility management inside the local domain is handled by a
Mobility Anchor Point (MAP). Mobility between separate MAP domains is handled by
MIPv6. The MAP basically acts as a local Home Agent. When a mobile node enters
into a new MAP domain it registers with it obtaining a regional care-of address
(RCoA). The RCoA is the address that the mobile node will use to inform its Home
Agent and correspondent nodes about its current location. Then, the packets will be
sent to and intercepted by the MAP, acting as a proxy, and routed inside the domain
to the on-link care-of address (LCoA). When a mobile node then performs a handoff
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between two access points within the same MAP domain only the MAP has to be
informed. Note, however that this does not imply any change to the periodic BUs a
MN has to sent to HA, CNs and now additionally to the MAP.
HMIPv6 presents the following advantages: it includes a mechanism to reduce the
signaling load in case of handoffs within the same domain and may improve handoff
performance reducing handoff latency and packet losses since intra-domain handoffs
are performed locally. However, since the periodic BUs is not reduced but the ones
due to handoffs, the gain depends on the mobility of the mobile nodes.
DHMP:
Dynamic hierarchical system architecture there is no fixed hierarchical architecture
for users or any restriction on the shape and the geographic location for subnets. In
the MIP protocol, an MH can determine if it enters a new subnet by detecting the
agent advertisement messages sent by the mobility agents (HAs or FAs). The MH
then obtains a new CoA and sends a location update message to it’s HA. Upon
receiving the message, the HA sets up a binding between the MH permanent
address and current CoA so that theHAcan intercept the packets to this MH and
tunnel them to the user’s current access point. The MHs in the MIP networks are
required to update their new CoA whenever they are changing their locations
(subnets) even though the MHs do not communicate with others. As shown in Fig. ,
this could result in significant signaling traffic to the network.
DHMIP location registration and call delivery:
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Comparison of the total costs for different schemes.
Hardware Interface
 Hard disk
: 40 GB
 RAM
: 512 MB
 Processor Speed
: 3.00GHz
 Processor
: Pentium IV Processor
Software Interface
 JDK 1.5
 Java Swing
 MS-Access
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