wdiff draft-ietf-netlmm-nohost-req-04.txt draft-ietf-netlmm-nohost-req-05.txt

Internet Draft J. Kempf, Editor
Document: draft-ietf-netlmm-nohost-req-04.txt August, draft-ietf-netlmm-nohost-req-05.txt October, 2006
Expires: Feburary, April, 2007

Goals for Network-based Localized Mobility Management (NETLMM)
(draft-ietf-netlmm-nohost-req-04.txt)
(draft-ietf-netlmm-nohost-req-05.txt)

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Contributors

Gerardo Giaretta, Kent Leung, Katsutoshi Nishida, Phil Roberts, and
Marco Liebsch all contributed major effort to this document. Their
names are not included in the authors' section due to the RFC
Editor's limit of 5 names.

Abstract

In this document, design goals for a network-based localized
mobility management (NETLMM) protocol are discussed.

Table of Contents

1.0 Introduction............................................2
2.0 NETLMM Functional Architecture..........................3
3.0 Goals for Localized Mobility Management.................2
3.0 the NETLMM Protocol...........................3
4.0 IANA Considerations....................................10
4.0 Security Considerations................................10
5.0 Acknowledgements.......................................11 Security Considerations................................11
6.0 Acknowledgements.......................................11
7.0 Author's Addresses.....................................11
7.0 Informative References.................................12
8.0 Appendix: Gap Analysis.................................13 Normative References...................................12
9.0 IPR Statements.........................................23 Informative References.................................12
10.0 IPR Statements.........................................13
11.0 Disclaimer of Validity.................................23
11.0 Validity.................................13
12.0 Copyright Notice.......................................23 Notice.......................................13

1.0 Introduction

In [9], [1], the basic problems that occur when a global mobility
protocol is used for managing local mobility are described, and two
basic
currently used approaches to localized mobility management - the
host-based approach that is used by most IETF protocols, and the
proprietary WLAN switch approach used between WLAN switches in
different subnets - are examined. The conclusion from the problem
statement document is that none of the approaches has a complete
solution to the problem. While the WLAN switch approach is most
convenient for network operators and users because it requires no
software on the mobile node other than the standard drivers for
WiFi, the proprietary nature limits interoperability and the
restriction to a single wireless last hop link type and wired backhaul link
type restricts scalability. The IETF host-based protocols require
host software stack changes that may not be compatible with all
global mobility protocols, and also require specialized and complex
security transactions with the network that may limit
deployability. The use
of an IGP to distribute host routes has scalability conclusion was that a localized mobility
management protocol that was network based and deployment
limitations. required no software
on the host for localized mobility management is desirable.

This document develops more a brief functional architecture and detailed
goals for a network-based localized mobility management protocol. protocol
(NETLMM). Section 2.0 describes the functional architecture of
NETLMM. In Section 2.0, we review 3.0, a list of goals that are desirable in a network-based localized
mobility management solution. the
NETLMM protocol is presented. Section 3.0 4.0 concerns IANA
considerations. Section 5.0 briefly outlines security
considerations. More discussion of security can be found in the
threat analysis document [20]. The architecture of the NETLMM
protocol for which the goals in this document have been formulated
is described in Section 5 of [9]. [2].

1.1 Terminology

Mobility terminology in this draft follows that in RFC 3753 [13] [10]
and in [9].

2.0 Goals for [1]. In addition, the following terms are related to the
functional architecture described in Section 2.0:

Localized Mobility Management Domain

An Access Network in the sense defined in [1] in which
mobility is handled by the NETLMM protocol.

Mobile Access Gateway
A Mobile Access Gateway (MAG) is a functional network
element that terminates a specific edge link and tracks
mobile node IP level mobility between edge links, through
NETLMM signaling with the Localized Mobility Anchor. The MAG
also terminates host routed data traffic from the Localized
Mobility Anchor for mobile nodes currently located within
the edge link under the MAG's control, and forwards data
traffic from mobile nodes on the edge link under its control
to the Localized Mobility Anchor.

Local Mobility Anchor

A Local Mobility Anchor (LMA) is a router that maintains a
collection of host routes and associated forwarding
information for mobile nodes within a localized mobility
management domain under its control. Together with the MAGs
associated with it, the LMA uses the NETLMM protocol to
manage IP node mobility within the localized mobility
management domain. Routing of mobile node data traffic is
anchored at the LMA as the mobile node moves around within
the localized mobility management domain.

2.0 NETLMM Functional Architecture

The NETLMM architecture consists of the following components.
Localized Mobility Anchors (LMAs) within the backbone network
maintain a collection of routes for individual mobile nodes within
the localized mobility management domain. The routes point to the
Mobile Access Gateways (MAGs) managing the links on which the
mobile nodes currently are located. Packets for a mobile node are
routed to and from the mobile node through tunnels between the LMA
and MAG. When a mobile node moves from one link to another, the MAG
sends a route update to the LMA. While some mobile node involvement
is necessary and expected for generic mobility functions such as
movement detection and to inform the MAG about mobile node
movement, no specific mobile node to network protocol will be
required for localized mobility management itself. Host stack
involvement in mobility management is thereby limited to generic
mobility functions at the IP layer, and no specialized localized
mobility management software is required.

3.0 Goals for the NETLMM Protocol

Section 2 of [9] [1] describes three problems with using a global
mobility management protocol for localized mobility management. Any
localized mobility management protocol must naturally address these
three problems. In addition, the side effects of introducing such a
solution into the network need to be limited. In this section, we
address goals on a localized mobility solution for NETLMM including both solving the basic problems
(Goals 1, 2, 3) and limiting the side effects (Goals 4+).

Some basic goals of all IETF protocols are not discussed in detail
here, but any solution is expected to satisfy them. These goals are
fault tolerance, robustness, interoperability, scalability, and
minimal specialized network equipment. A good discussion of their
applicability to IETF protocols can be found in [3]. [4].

Out of scope for the initial goals discussion are QoS, multicast, QoS and dormant
mode/paging. While these are important functions for mobile nodes,
they are not part of the base localized mobility management
problem. In addition, mobility between localized mobility
management domains is not covered here. It is assumed that this is
covered by the global mobility management protocols.

2.1

3.1 Handover Performance Improvement (Goal #1)

Handover packet loss occurs because there is usually latency
between when the wireless link handover starts and when the IP subnet
configuration and global mobility management signaling completes.
During this time the mobile node is unreachable at its former
topological location on the old link where correspondents are
sending packets and to which they are being forwarded. packets. Such misrouted packets are dropped. This aspect of
handover performance optimization has been the subject of an enormous amount of much
work, both in other SDOs, to reduce the latency of wireless link
handover, SDOs and in the IETF and elsewhere, IETF, in order to reduce the
latency in IP handover. Many solutions to this problem have been
proposed at the
wireless link layer and at the IP layer. One aspect of this
goal for localized mobility management is that the processing delay
for changing the forwarding after handover must approach as closely
as possible the sum of the delay associated with link layer
handover and the delay required for active IP layer movement
detection, in order to avoid excessive packet loss. Ideally, if
network-side link layer support is available for handling movement
detection prior to link handover or as part of the link handover
process, the routing update should complete within the time
required for wireless link handover. This delay is difficult to quantify,
but for voice traffic, the entire handover delay including Layer 2
handover time and IP handover time should be between 40-70 ms to
avoid any degradation in call quality. Of course, if the link layer
handover latency is too high, sufficient IP layer handover
performance for good real time service cannot be matched.

A goal of the NETLMM protocol - in networks where the link layer
handover latency allows it - is to reduce the loss amount of accurate forwarding
to reduce interruptions which may cause user-perceptible service
degradation for real time traffic such as voice.

2.2 latency in
IP handover, so that the combined IP and link layer handover
latency is less than 70 ms.

3.2 Reduction in Handover-related Signaling Volume (Goal #2)

Considering Mobile IPv6 [9] as the global mobility protocol (other
mobility protocols require about the same or somewhat less), if a
mobile node using address autoconfiguration is required to
reconfigure on every move between links, the following signaling
must be performed:

1) Link layer signaling required for handover and reauthentication.
For example, in 802.11 [6] [7] this is the Reassociate message
together with 802.1x [7] [8] reauthentication using EAP.
2) Active IP level movement detection, including router
reachability. The DNA protocol [4] [5] uses Router
Solicitation/Router Advertisement for this purpose. In addition,
if SEND [1] [3] is used and the mobile node does not have a
certificate cached for the router, the mobile node must use
Certification Path Solicitation/Certification Path Advertisement
to obtain a certification path.
3) Two Multicast Listener Discovery (MLD) [19] [14] REPORT messages, one
for each of the solicited node multicast addresses corresponding
to the link local address and the global address,
4) Two Neighbor Solicitation (NS) messages for duplicate address
detection, one for the link local address and one for the global
address. If the addresses are unique, no response will be
forthcoming.
5) Two NS messages from the router for address resolution of the
link local and global addresses, and two Neighbor Advertisement
messages in response from the mobile node,
6) Binding Update/Binding Acknowledgement between the mobile node
and home agent to update the care of address binding,
7) Return routability signaling between the correspondent node and
mobile node to establish the binding key, consisting of one Home
Test Init/Home Test and Care of Test Init/Care of Test,
8) Binding Update/Binding Acknowledgement between the correspondent
node and mobile node for route optimization.

Note that Steps 1-2 may be necessary, necessary even for intra-link mobility,
if the wireless last hop link protocol doesn't provide much help for IP
handover. Step 3-5 will be different if stateful address
configuration is used, since additional messages are required to
obtain the address. Steps 6-8 are only necessary when Mobile IPv6
is used. The result is approximately 18 messages at the IP level,
where the exact number depends on various specific factors such as
whether the mobile node has a router certificate cached or not,
before a mobile node can be ensured that it is established on a
link and has full IP connectivity. In addition to handover related
signaling, if the mobile node performs Mobile IPv6 route
optimization, it may be required to renew its return routability
key periodically (on the order of every 7 minutes) even if it is
not moving, resulting in additional signaling.

The signaling required has a large impact on the performance of
handover, impacting Goal #1. Perhaps more importantly, the
aggregate impact from many mobile nodes of such signaling on
expensive shared links (such as wireless where the capacity of the
link cannot easily be expanded) can result in reduced last hop link
capacity for data traffic. Additoinally, in links where the end
user is charged for IP traffic, IP signaling is not without cost.

To address the issue of signaling impact described above, the goal
is that handover signaling volume from the mobile node to the
network should be no more than what is needed for the mobile node
to perform secure IP level movement detection, in cases where no
link layer support exists. Furthermore, NETLMM should not introduce
any additional signaling during handover beyond what is required
for IP level movement detection. If link layer support exists for
IP level movement detection, the mobile node may not need to
perform any additional IP level signaling after link layer
handover.

2.3

3.3 Location privacy Privacy (Goal #3)
Although location privacy issues for Mobile IPv6 have been
discussed in [12], the location privacy referred to here focuses on
the IP layer.

In most wireless IP network deployments, different any IP
subnets are used to cover different geographical areas. It network, there is
therefore possible to derive a topological to geographical map, in
which particular IPv6 subnet prefixes are mapped to particular
geographical locations. The precision of the map depends on the
size of the geographic area covered by a particular subnet: if the
area is large, then knowing the subnet prefix won't provide much
information about threat that an attacker can determine
the precise geographical physical location of a mobile network node within from the subnet.

When node's topological
location. Depending on how an operator deploys their network, an
operator may choose to assign subnet coverage in a mobile node moves geographically, way that is
tightly bound to geography at some timescale or it also moves
topologically between subnets. In order may choose to maintain routability,
the mobile node must change its local IP address when
assign it moves
between subnets. If the mobile node sources packets with its local
IP address in the clear, for example through route optimization ways in
Mobile IPv6, the correspondent node or an eavesdropper can use which the
topological to geographical map to deduce in real time where threat of someone finding a
mobile node - and therefore
physically based on its user - IP address is located. Depending on how
precisely smaller. Allowing
the geographical location can L2 attachment and L3 address to be deduced, less tightly bound is one
tool for reducing this
information could be used to compromise the privacy or even cause
harm threat to the user. The geographical location information should not
be revealed to nor be deducible by the correspondent node or privacy.

Mobility introduces an
eavesdropper without the authorization of the mobile node's owner.

The threats to location privacy come in a variety of forms. One is
a man in the middle attack in which traffic between additional threat. An attacker can track a correspondent
and the mobile node is intercepted and the
mobile node's geographical location
is deduced from that. Others are attacks in which the correspondent
itself is the attacker, and the correspondent deliberately starts a
session with real time, if the victim
mobile node in order to track must change its location by
noting the source IP address of packets originating as it moves from one subnet
to another through the mobile
node. Note that covered geographical area. If the location privacy referred to here
granularity of the mapping between the IP subnets and geographical
area is different
from small for the location privacy discussed in [12]. The location privacy
discussed particular link type in these drafts primarily concerns modifications to use, the
Mobile IPv6 protocol attacker can
potentially assemble enough information to eliminate places where an eavesdropper
could track find the mobile node's movement by correlating home address
and care of address. victim in real
time.

In order to reduce the risk from location privacy compromises as a
result of IP address changes, the goal for NETLMM is to remove the
need to change IP address as a mobile node moves across links. links in an
access network. Keeping the IP address fixed removes any possibility for the
correspondent node to deduce the precise geographic location of the
mobile node without the user's authorization. Note that keeping the
address constant doesn't completely remove the possibility of
deducing the geographical location, since over a local address still is
required. However, it does allow large
geographical region fuzzes out the network to be deployed such
that resolution of the mapping
between the geographic IP subnets and topological location is
considerably less precise. If the mapping is not precise, an
attacker can only deduce in real time that the mobile node is
somewhere in a large geographic geographical area, like, for example, a
metropolitan region or even a regardless of how
small country, reducing reducing the natural deployment granularity of the location information.

2.4 Efficient Use of Wireless Resources (Goal #4)

Advances in wireless physical layer and medium access control layer
technology continue to increase the bandwidth available from
limited wireless spectrum, but even with technology increases,
wireless spectrum remains a limited resource. Unlike wired network
links, wireless links are constrained in the number of bits/Hertz
by their coding technology and use of physical spectrum, which is
fixed by the physical layer. It is not possible to lay an extra
cable if the link becomes increasingly congested as is the case
with wired links.

While header compression technology can remove header overhead, it
does not come without cost. Requiring header compression on the
wireless access points increases the cost and complexity of the
access points, and increases the amount of processing required for
traffic across the wireless link. Header compression also requires
special software on the host, which may or may not be present.
Since be. This reduces the access points tend to be a critical bottleneck in
wireless access networks for real time traffic (especially on
chance that the
downlink), reducing attacker can deduce the amount precise geographic location
of per-packet processing is
important. While header compression probably cannot be completely
eliminated, especially for real time media traffic, simplifying
compression to reduce processing cost is an important goal.

The goal is that the localized mobility management protocol should
not introduce any new signaling or increase existing signaling over
the air.

2.5 mobile node.

3.4 Limit the Signaling Overhead in the Network (Goal #5)

While bandwidth and router processing resources are typically not
as constrained in #4)

Access networks, including both the wired network, access networks and wireless parts, tend
to have somewhat stronger bandwidth and router processing
constraints than the backbone. These In the wired part of the network,
these constraints are a function of the cost of laying fiber or
wiring to the wireless access points in a widely dispersed
geographic area. In the wireless part of the network, these
constraints are due to the limitation on the number of bits per
Hertz imposed by the physical layer protocol. Therefore, any
solutions for localized mobility management should minimize signaling
overhead within the wired
network as well.

2.6 No Extra Security Between access network.

3.5 Simplify Mobile Node and Mobility Management Security by Deriving from
IP Network Access and/or IP Movement Detection Security (Goal #6) #5)

Localized mobility management protocols that have signaling between
the mobile node and network host involvement
may require a an additional security association between the mobile
node and the network entity that is the target of the
signaling. Establishing a mobility anchor, and establishing this security
association specifically for
localized mobility service in a roaming situation may prove
difficult, because provisioning a require additional signaling between the mobile
node with security
credentials for authenticating and authorizing localized the mobility
service in each roaming partner's network may be unrealistic from a
deployment perspective. anchor (see [13] for an example). The
additional security association requires extra signaling and
therefore extra time to negotiate. Reducing the complexity of
mobile node to network security for localized mobility management
can therefore reduce barriers to deployment.

If deployment and improve
responsiveness. Naturally, such simplification must not come at the access router deduces
expense of maintaining strong security guarantees for both the
network and mobile node.

In NETLMM, the network (specifically the MAG) derives the
occurrence of a mobility event requiring a routing update for a
mobile node movement based on active
IP-level from link layer handover signaling or IP layer movement
detection by signaling from the mobile node, then authentication node. This information is required used
to update routing for the IP-level mobile node at the LMA. The handover or
movement detection messages from signaling must provide the
mobile node to ensure network with proper
authentication and authorization so that the network can
definitively identify the mobile node is authorized to possess
the address used for the movement detection. and determine its
authorization. The authorization may be at the IP level level, for
example, using something like SEND [3] to secure IP movement
detection signaling, or it may be tied to at the original network access link level. Proper
authentication and wireless link layer authorization for handover.
Some wireless must be implemeted on link layers, especially cellular protocols, feature
full support and strong security for layer
handover at the link level,
and require no signaling and/or IP support level movement detection signaling in
order for handover. If such wireless link
security is not available, however, then it must be provided at the
IP level. MAG to securely deduce mobile node movement events.
Security threats to the NETLMM protocol are discussed in
[20].

In summary, ruling out mobile node involvement in local mobility
management simplifies [2].

The goal is that security by removing the need for service-
specific credentials to authenticate and authorize the NETLMM mobile node
for localized mobility
management in the network. This puts
localized mobility management on the same level as basic should derive from IP
routing. Hosts obtain this service network access and/or IP movement
detection security, such as part of their SEND or network access.

The goal is that support for localized mobility management should access authentication,
and not require any additional security associations or additional
signaling between the mobile node and the network other
than that required for network access or local link security (such
as SEND [1]).

2.7 Wireless network.

3.6 Link Technology Agnostic (Goal #7) #6)

The number of wireless link technologies available is growing, and
the growth seems unlikely to slow down. Since the standardization
of a wireless link physical and medium access control layers is a
time consuming process, reducing the amount of work necessary to
interface a particular wireless link technology to an IP network is
necessary. A When the last hop link is a wireless link, a localized
mobility management solution should ideally require minimal work to
interface with a new wireless link technology.

In addition, an edge mobility solution should provide support for
multiple wireless link technologies. It is not required that the
localized mobility management solution support handover from one
wireless link technology to another without change in IP address,
but this possibility should not be precluded.

The goal is that the localized mobility management protocol should
not use any wireless link specific information for basic routing
management, though it may be used for other purposes, such as
securely identifying a mobile node.

2.8

3.7 Support for Unmodified Mobile Nodes (Goal #8) #7)

In the wireless LAN switching market, no modification of the
software on the mobile node is required to achieve localized
mobility management. Being able to accommodate unmodified mobile
nodes enables a service provider to offer service to as many
customers as possible, the only constraint being that the customer
is authorized for network access.

Another advantage of minimizing mobile node software for localized
mobility management is that multiple global mobility management
protocols can be supported. There are a variety of global mobility
management protocols that might also need support, including
proprietary or wireless link technology-specific protocols needing support
for backward compatibility reasons. Within the Internet, both HIP [14]
[11] and Mobike [5] [6] are likely to need support in addition to
Mobile IPv6, IPv6 [9], and Mobile IPv4 [12] support may also be
necessary.

Note that this goal does NOT mean that the mobile node has no
software at all associated with mobility or wireless. mobility. The mobile node must have
some kind of global mobility protocol if it is to move from one
domain of edge mobility support to another and maintain session
continuity, although no global mobility protocol is required if the
mobile node only moves within the coverage area of the localized
mobility management protocol or no session continuity is required
during global movement. Also, if the last hop link is a wireless
link, every wireless link protocol requires handover support on the
mobile node in the physical and medium access control layers,
typically in the wireless interface driver. Information passed from
the medium access control layer to the IP layer on the mobile node
may be necessary to trigger IP signaling for IP handover. Such
movement detection support at the IP level may be required in order
to determine whether the mobile node's default router is still
reachable after the move to a new access point has occurred at the
medium access control layer. Whether or not such support is
required depends on whether the medium access control layer can
completely hide link movement from the IP layer. For a cellular type
wireless link protocol such as the 3G protocols, the mobile node and network undergo an
extensive negotiation at the medium access control layer prior to
handover, so it may be possible to trigger routing update without
any IP protocol involvement. However, for a wireless link protocol
such as IEEE 802.11 [7] in which the decision for handover is
entirely in the hands of the mobile node, IP layer movement
detection signaling from the mobile node may be required to trigger
a routing update.

The goal is that the localized mobility management solution should
be able to support any mobile node that joins the link and that has
a wireless interface that can communicate with the network, without
requiring localized mobility management software on the mobile
node.

2.9

3.8 Support for IPv4 and IPv6 (Goal #9) #8)

While most of this document is written with IPv6 in mind, localized
mobility management is a problem in IPv4 networks as well. A
solution for localized mobility that works for both versions of IP
is desirable, though the actual protocol may be slightly different
due to the technical details of how each IP version works. From
Goal #8 #7 (Section 2.8), 3.7), minimizing mobile node support for localized
mobility means that ideally no IP version-specific changes would should
be required on the mobile node for localized mobility, and that
global mobility protocols for both IPv4 and IPv6 should be
supported. Any IP version-specific features would should be confined to
the network protocol.

2.10

3.9 Re-use of Existing Protocols Where Sensible (Goal #10) #9)

Many existing protocols are available as Internet Standards upon
which the NETLMM protocol can be built. The design of the protocol
should have a goal to re-use existing protocols where it makes
architectural and engineering sense to do so. The design should
not, however, attempt to re-use existing protocols where there is
no real architectural or engineering reason. For example, the suite
of Internet Standards contains several good candidate protocols for
the transport layer, so there is no real need to develop a new
transport protocol specifically for NETLMM. Re-use is clearly a
good engineering decision in this case, since backward
compatibility with existing protocol stacks is important. On the
other hand, the network-based, localized mobility management
functionality being introduced by NETLMM is a new piece of
functionality, and therefore any decision about whether to re-use
an existing global mobility management protocol should carefully
consider whether re-using such a protocol really meets the needs of
the functional architecture for network-based localized mobility
management. The case for re-use is not so clear in this case, since
there is no compelling backward compatibility argument.

2.11

3.10 Localized Mobility Management Independent of Global Mobility
Management (Goal #10)

Localized mobility management should be implementable and
deployable independently of any global mobility management
protocol. This enables the choice of local and global mobility
management to be made independently of particular protocols that
are implemented and deployed to solve the two different sorts of
mobility management problems. The operator can choose a particular
localized mobility management protocol according to the specific
features of their access network. It can subsequently upgrade the
localized mobility management protocol on its own, without even
informing the mobile nodes. Similarly, the mobile nodes can use a
global mobility management protocol that best suits their
requirements, or even not use one at all. Also, a mobile node can
move into a new access network without having to check that it
understands the localized mobility management protocol being used
there.

The goal is that the implementation and deployment of the localized
mobility management protocol should not restrict, or be restricted
by, the choice of global mobility management protocol.

2.12

3.11 Configurable Data Plane Forwarding between Local Mobility Anchor
and Mobile Access Router Gateway (Goal #11)

Different network operators may require different types of
forwarding options between the mobility anchor LMA and the access
routers MAGs for mobile node
data plane traffic. An obvious forwarding option that has been used
in past IETF localized mobility management protocols is IP-IP
encapsulation for bidirectional tunneling. The tunnel endpoints could be are
the mobility anchor LMA and the access routers. MAGs. But other options are possible. Some network
deployments may prefer routing-based solutions. Others may require
security tunnels using IPsec ESP encapsulation if part of the
localized mobility management domain runs over a public access
network and the network operator wants to protect the traffic.

A goal of the NETLMM protocol is to allow the forwarding between
the mobility anchor LMA and access routers MAGs to be configurable depending on the particulars of
the network deployment. Configurability is not expected to be
dynamic as in controlled by the arrival of a mobile node; but
rather, configuration is expected to be similar in time scale to
configuration for routing. The NETLMM protocol may designate a
default forwarding mechanism. It is also possible that additional
work may be required to specify the interaction between a
particular forwarding mechanism and the NETLMM protocol, but this
work is not in scope of the NETLMM base protocol.

3.0

4.0 IANA Considerations

There are no IANA considerations for this document.

4.0

5.0 Security Considerations

There are two kinds of security issues involved in network-based
localized mobility management: security between the mobile node and
the network, and security between network elements that participate
in the network-based localized mobility management protocol

Security between the mobile node and the network itself consists of
two parts: threats involved NETLMM protocol. The security-related goals in localized mobility management this
document, described in
general, Section 3.3 and threats to 3.5, focus on the former,
because those are unique to network-based localized mobility
management from the host. The first is discussed above in Sections
2.3 and 2.6. management. The second is discussed in the
threat analysis document [20].

For threats to network-based localized mobility management, the
basic threat is an attempt by an unauthorized party to signal [2] contains a
bogus mobility event. Such an event must be detectable. This
requires proper mutual authentication and authorization more detailed discussion of network
elements that participate in the network-based localized mobility
management protocol, and data origin authentication on
both kinds of threats, which the
signaling traffic between network elements.

5.0 protocol design must address.

6.0 Acknowledgements

The authors would like to acknowledge the following for
particularly diligent reviewing: Vijay Devarapalli, Peter McCann,
Gabriel Montenegro, Vidya Narayanan, Pekka Savola, and Fred
Templin.

6.0

7.0 Author's Addresses

James Kempf
DoCoMo USA Labs
181 Metro Drive, Suite 300
San Jose, CA 95110
USA
Phone: +1 408 451 4711
Email: kempf@docomolabs-usa.com

Kent Leung
Cisco Systems, Inc.
170 West Tasman Drive
San Jose, CA 95134
USA
EMail: kleung@cisco.com

Phil Roberts
Motorola Labs
Schaumberg, IL
USA
Email: phil.roberts@motorola.com

Katsutoshi Nishida
NTT DoCoMo Inc.
3-5 Hikarino-oka, Yokosuka-shi
Kanagawa,
Japan
Phone: +81 46 840 3545
Email: nishidak@nttdocomo.co.jp

Gerardo Giaretta
Telecom Italia Lab
via G. Reiss Romoli, 274
10148 Torino
Italy
Phone: +39 011 2286904
Email: gerardo.giaretta@tilab.com

Marco Liebsch
NEC Network Laboratories
Kurfuersten-Anlage 36
69115 Heidelberg
Germany
Phone: +49 6221-90511-46
Email: marco.liebsch@ccrle.nec.de

7.0 Informative

8.0 Normative References

[1] Kempf, J., editor, "Problem Statement for IP Local Mobility,"
Internet Draft, Work in Progress.
[2] Vogt, C., and Kempf, J., "Security Threats to Network-based
Localized Mobility Management", Internet Draft, Work in
Progress.

9.0 Informative References

[3] Arkko, J., Kempf, J., Zill, B., and Nikander, P., "SEcure
Neighbor Discovery (SEND)", RFC 3971, March, 2005.
[2] Campbell, A., Gomez, J., Kim, S., Valko, A., and Wan, C.,
"Design, Implementation and Evaluation of Cellular IP", IEEE
Personal Communications, June/July 2000.
[3]
[4] Carpenter, B., "Architectural Principles of the Internet,"
RFC 1958, June, 1996.
[4]
[5] Choi, J, and Daley, G., "Goals of Detecting Network
Attachment in IPv6", Internet Draft, Work in Progress.
[5]
[6] Eronen, P., editor, "IKEv2 Mobility and Multihoming Protocol
(MOBIKE)", RFC 4555, June 2006.
[6]
[7] IEEE, "Wireless LAN Medium Access Control (MAC)and Physical
Layer (PHY) specifications", IEEE Std. 802.11, 1999.
[7]
[8] IEEE, "Port-based Access Control", IEEE LAN/MAN Standard
802.1x, June, 2001.
[8]
[9] Johnson, D., Perkins, C., and Arkko, J., "Mobility Support in
IPv6", RFC 3775.
[9] Kempf, J., editor, "Problem Statement for IP Local Mobility,"
Internet Draft, Work in Progress. 3775, June, 2004.
[10] Kempf, J., and Koodli, R., "Distributing a Symmetric FMIPv6
Handover Key using SEND", Internet Draft, Work in Progress.
[11] Koodli, R., editor, "Fast Handovers for Mobile IPv6", RFC
4068, July, 2005.
[12] Koodli, R., " IP Address Location Privacy and Mobile IPv6:
Problem Statement", Internet Draft, Work in Progress.
[13] Manner, J., and Kojo, M., "Mobility Related Terminology", RFC
3753, June, 2004.
[14]
[11] Moskowitz, R., and Nikander, P., "Host Identity Protocol
(HIP) Architecture", RFC 4423, May, 2006.
[15] Narayanan, V., Venkitaraman, N., Tschofenig, H., Giaretta,
G., and Bournelle, J., "Handover Keys Using AAA", Internet
Draft, Work in Progress.

[16] Ramjee, R., La Porta, T., Thuel, S., and Varadhan, K.,
"HAWAII: A domain-based approach for supporting mobility in
wide-area wireless networks", in Proceedings of the
International Conference on Networking Protocols (ICNP),
1999.
[17] Soliman, H., Tsirtsis, G., Devarapalli, V., Kempf, J.,
Levkowetz, H., Thubert, P, and Wakikawa, R. "Dual Stack
Mobile IPv6 (DSMIPv6)
[12] Perkins, C., "IP Mobility Support for Hosts and Routers", Internet Draft,
Work in Progress.
[18] IPv4", RFC 3344,
August, 2002.
[13] Soliman, H., Castelluccia, C., El Malki, K., and Bellier, L.,
"Hierarchical Mobile IPv6 Mobility Management (HMIPv6)", RFC
4140, August, 2005.
[19]
[14] Vida, R., and Costa, L., " Multicast Listener Discovery
Version 2 (MLDv2) for IPv6", RFC 3810, June 2004.
[20] Vogt, C., and Kempf, J., "Security Threats to Network-based
Localized Mobillity Management", Internet Draft, Work in
Progress.

8.0 Appendix: Gap Analysis

This section discusses a gap analysis between existing proposals
for solving localized mobility management and the goals in Section.
2.0.

8.1 Mobile IPv6 with Local Home Agent

One option is to deploy Mobile IPv6 with a locally assigned home
agent in the local network. This solution requires the mobile node
to somehow be assigned a home agent in the local network when it
boots up. This home agent is used instead of the home agent in the
home network. The advantage of this option is that no special
solution is required for edge mobility - the mobile node reuses the
global mobility management protocol for that purpose - if the
mobile node is using Mobile IPv6.

The analysis of this approach against the goals above is the
following.

Goal #1 Handover Performance Improvement: If the mobile node does
not perform route optimization, this solution reduces, but does not
eliminate, IP handover related performance problems.

Goal #2 Reduction in Handover-related Signaling Volume: Similarly
to Goal #1, signaling volume is reduced if no route optimization
signaling is done on handover.

Goal #3 Location privacy: Location privacy is preserved for
external correspondents as long as all of the mobile node's traffic
is routed through the local HA.

Goal #4 Efficient Use of Wireless Resources: If traffic is not
route optimized, the mobile node still pays for an over-the-air
tunnel to the locally assigned home agent. The overhead here is
exactly the same as if the mobile node's home agent in the home
network is used and route optimization is not done.

Goal #5 Limit the Signaling Overhead in the Network: If the
localized mobility management domain is large, the mobile node may
suffer from unoptimzed routes. RFC 3775 [8] provides no support for
notifying a mobile node that another localized home agent is
available for a more optimized route, or for handing over between
home agents. A mobile node would have to perform the full home
agent bootstrap procedure, including establishing a new IPsec SA
with the new home agent.

Goal #6 No Extra Security Between Mobile Node and Network: A local
home agent in a roaming situation requires the guest mobile node to
have the proper credentials to authenticate with the local home
agent in the serving network. The credentials used for network
access authentication could also be used for mobile service
authentication and authorization if the local home agent uses EAP
over IKEv2 to authenticate the mobile node with its home AAA
server. This may require additional authorization between the home
and visited networks to use the same credentials for a different
service, however. In addition, as in Goal #3, if binding updates
are done in cleartext over the access network or the mobile node
has become infected with malware, the local home agent's address
could be revealed to attackers and the local home agent could
become the target of a DoS attack. So a local home agent would
provide no benefit for this goal.

Goal #7 Support for Heterogeneous Wireless Link Technologies: This
solution supports multiple wireless technologies with separate IP
subnets for different links. No special work is required to
interface a local home agent to different wireless technologies.

Goal #8 Support for Unmodified Mobile Nodes: The mobile node must
support Mobile IPv6 in order for this option to work. So mobile
node changes are required and other IP mobility protocols are not
supported.

Goal #9 Support for IPv4 and IPv6: The Mobile IPv6 working group is
working on modifying the protocol to allow registration of IPv4
care of addresses in an IPv6 home agent, and also to allow a mobile
node to have an IPv4 care of address [17].

Goal #10 Re-use of Existing Protocols Where Sensible: This solution
re-uses an existing protocol, Mobile IPv6.

Goal #11 Localized Mobility Management Independent of Global
Mobility Management: This solution merges localized mobility
management and global mobility management, so it does not support
the goal.

8.2 Hierarchical Mobile IPv6 (HMIPv6)

HMIPv6 [18] provides the most complete localized mobility
management solution available today. In HMIPv6, a localized
mobility anchor called a MAP serves as a routing anchor for a
regional care of address. When a mobile node moves from one access
router to another, the mobile node changes the binding between its
regional care of address and local care of address at the MAP. No
global mobility management signaling is required, since the care of
address seen by correspondents does not change. This part of HMIPv6
is similar to the solution outlined in Section 8.1; however, HMIPv6
also allows a mobile node to hand over between MAPs.

Handover between MAPs and MAP discovery requires configuration on
the routers. MAP addresses are advertised by access routers.
Handover happens by overlapping MAP coverage areas so that, for
some number of access routers, more than one MAP may be advertised.
Mobile nodes need to switch MAPs in the transition area, and then
must perform global mobility management update and route
optimization to the new regional care of address, if appropriate.

The analysis of this approach against the goals above is the
following.

Goal #1 Handover Performance Improvement: This solution shortens,
but does not eliminate, the latency associated with IP handover,
since it reduces the amount of signaling and the length of the
signaling paths.

Goal #2 Reduction in Handover-related Signaling Volume: Signaling
volume is reduced simply because no route optimization signaling is
done on handover within the coverage area of the MAP.

Goal #3 Location privacy: Location privacy is preserved for
external correspondents.

Goal #4 Use of Wireless Resources: The mobile node always pays for
an over-the-air tunnel to the MAP. If the mobile node is tunneling
through a global home agent or VPN gateway, the wired link
experiences double tunneling. Over-the-air tunnel overhead can be
removed by header compression, however.

Goal #5 Limit the Signaling Overhead in the Network: From Goal #1
and Goal #4, the signaling overhead is no more or less than for
mobile nodes whose global mobility management anchor is local.
However, because MAP handover is possible, forwarding across large
localized mobility management domains can be improved thereby
improving wired network resource utilization by using multiple MAPs
and handing over, at the expense of the configuration and
management overhead involved in maintaining multiple MAP coverage
areas.

Goal #6 Extra Security Between Mobile Node and Network: In a
roaming situation, the guest mobile node must have the proper
credentials to authenticate with the MAP in the serving network. In
addition, since the mobile node is required to have a unicast
address for the MAP that is either globally routed or routing
restricted to the local administrative domain, the MAP is
potentially a target for DoS attacks across a wide swath of network
topology.

Goal #7 Support for Heterogeneous Wireless Link Technologies: This
solution supports multiple wireless technologies with separate IP
subnets for different links.

Goal #8 Support for Unmodified Mobile Nodes: This solution requires
modification to the mobile nodes. In addition, the HMIPv6 design
has been optimized for Mobile IPv6 mobile nodes, and is not a good
match for other global mobility management protocols.

Goal #9 Currently, there is no IPv4 version of this protocol;
although there is an expired Internet draft with a design for a
regional registration protocol for Mobile IPv4 that has similar
functionality. It is possible that the same IPv4 transition
solution as used for Mobile IPv6 could be used [17] above.

Goal #10 Re-use of Existing Protocols Where Sensible: This solution
re-uses an existing protocol, HMIPv6.

Goal #11 Localized Mobility Management Independent of Global
Mobility Management: While HIMPv6 is technically a separate
protocol from MIPv6 and could in principle be implemented and
deployed without MIPv6, the design is very similar and
implementation and deployment would be easier if the mobile nodes
supported MIPv6.

8.3 Combinations of Mobile IPv6 with Optimizations

One approach to local mobility that has received much attention in
the past and has been thought to provide a solution is combinations
of protocols. The general approach is to try to cover gaps in the
solution provided by MIPv6 by using other protocols. In this
section, gap analyses for MIPv6 + FMIPv6 and HMIPv6 + FMIPv6 are
discussed.

8.3.1 MIPv6 with local home agent + FMIPv6

As discussed in Section 8.1, the use of MIPv6 with a dynamically
assigned, local home agent cannot fulfill the goals. A fundamental
limitation is that Mobile IPv6 cannot provide seamless handover
(i.e. Goal #1). FMIPv6 [11] above has been defined with the intent
to improve the handover performance of MIPv6. For this reason, the
combined usage of FMIPv6 and MIPv6 with a dynamically assigned
local home agent has been proposed to handle local mobility.

Note that this gap analysis only applies to localized mobility
management, and it is possible that MIPv6 and FMIPv6 might still be
acceptable for global mobility management.

The analysis of this combined approach against the goals follows.

Goal #1 Handover Performance Improvement: FMIPv6 provides a
solution for handover performance improvement that should fulfill
the goals raised by real-time applications in terms of jitter,
delay and packet loss. The location of the home agent (in local or
home domain) does not affect the handover latency.

Goal #2 Reduction in Handover-related Signaling Volume: FMIPv6
requires the mobile node to perform extra signaling with the access
router (i.e. exchange of RtSolPr/PrRtAdv and FBU/FBA). Moreover, as
in standard MIPv6, whenever the mobile node moves to another link,
it must send a Binding Update to the home agent. If route
optimization is used, the mobile node also performs return
routability and sends a Binding Update to each correspondent node.
Nonetheless, it is worth noting that FMIPv6 should result in a
reduction of the amount of IPv6 Neighbor Discovery signaling on the
new link.

Goal #3 Location privacy: The mobile node maintains a local care of
address. If route optimization is not used, location privacy can be
achieved using bi-directional tunneling.

Goal #4 Use of Wireless Resources: As stated for Goal #2, the
combination of MIPv6 and FMIPv6 generates extra signaling overhead.
For data packets, in addition to the Mobile IPv6 over-the-air
tunnel, there is a further level of tunneling between the mobile
node and the previous access router during handover. This tunnel is
needed to forward incoming packets to the mobile node addressed to
the previous care of address. Another reason is that, even if the
mobile node has a valid new care of address, the mobile node cannot
use the new care of address directly with its correspondents
without performing route optimization to the new care of address.
This implies that the transient tunnel overhead is in place even
for route optimized traffic.

Goal #5 Limit the Signaling Overhead in the Network: FMIPv6
generates extra signaling overhead between the previous access
router and the new access router for the HI/HAck exchange.
Concerning data packets, the use of FMIPv6 for handover performance
improvement implies a tunnel between the previous access router and
the mobile node that adds some overhead in the wired network. This
overhead has more impact on star topology deployments, since
packets are routed down to the old access router, then back up to
the aggregation router and then back down to the new access router.

Goal #6 Extra Security Between Mobile Node and Network: In addition
to the analysis for Mobile IPv6 with local home agent in Section
8.1, FMIPv6 requires the mobile node and the previous access router
to share a security association in order to secure FBU/FBA
exchange. Two solutions have been proposed: a SEND-based solution
[10] above and an AAA-based solution [15]. Both solutions require
additional support on the mobile node and in the network beyond
what is required for network access authentication.

Goal #7 Support for Heterogeneous Wireless Link Technologies: MIPv6
and FMIPv6 support multiple wireless technologies, so this goal is
fulfilled.

Goal #8 Support for Unmodified Mobile Nodes: The mobile node must
support both MIPv6 and FMIPv6, so it is not possible to satisfy
this goal.

Goal #9 Support for IPv4 and IPv6: Work is underway to extend MIPv6
with the capability to run over both IPv6-enabled and IPv4-only
networks [17] above. FMIPv6 only supports IPv6. Even though an IPv4
version of FMIP has been recently proposed, it is not clear how it
could be used together with FMIPv6 in order to handle fast
handovers across any wired network.

Goal #10 Re-use of Existing Protocols Where Sensible: This solution
re-uses existing protocols, Mobile IPv6 and FMIPv6.

Goal #11 Localized Mobility Management Independent of Global
Mobility Management: This solution merges localized mobility
management and global mobility management, so it does not support
the goal.

8.3.2 HMIPv6 + FMIPv6

HMIPv6 provides several advantages in terms of local mobility
management. However, as seen in Section 8.2, it does not fulfill
all the goals identified in Section 2.0. In particular, HMIPv6 does
not completely eliminate the IP handover latency. For this reason,
FMIPv6 could be used together with HMIPv6 in order to cover the
gap.

Note that even if this solution is used, the mobile node is likely
to need MIPv6 for global mobility management, in contrast with the
MIPv6 with dynamically assigned local home agent + FMIPv6 solution.
Thus, this solution should really be considered MIPv6 + HMIPv6 +
FMIPv6.

The analysis of this combined approach against the goals follows.

Goal #1 Handover Performance Improvement: HMIPv6 and FMIPv6 both
shorten the latency associated with IP handovers. In particular,
FMIPv6 is expected to fulfill the goals on jitter, delay and packet
loss raised by real-time applications.

Goal #2 Reduction in Handover-related Signaling Volume: Both FMIPv6
and HMIPv6 require extra signaling compared with Mobile IPv6. As a
whole the mobile node performs signaling message exchanges at each
handover that are RtSolPr/PrRtAdv, FBU/FBA, LBU/LBA and BU/BA.
However, as mentioned in Section 8.2, the use of HMIPv6 reduces the
signaling overhead since no route optimization signaling is done
for intra-MAP handovers. In addition, naive combinations of FMIPv6
and HMIPv6 often result in redundant signaling. There is much work
in the academic literature and the IETF on more refined ways of
combining signaling from the two protocols to avoid redundant
signaling.

Goal #3 Location privacy: HMIPv6 may preserve location privacy,
depending on the dimension of the geographic area covered by the
MAP.

Goal #4 Use of Wireless Resources: As mentioned for Goal #2, the
combination of HMIPv6 and FMIPv6 generates a lot of signaling
overhead in the network. Concerning payload data, in addition to
the over-the-air MIPv6 tunnel, a further level of tunneling is
established between mobile node and MAP. Notice that this tunnel is
in place even for route optimized traffic. Moreover, if FMIPv6 is
directly applied to HMIPv6 networks, there is a third temporary
handover-related tunnel between the mobile node and previous access
router. Again, there is much work in the academic literature and
IETF on ways to reduce the extra tunnel overhead on handover by
combining HMIP and FMIP tunneling.

Goal #5 Limit the Signaling Overhead in the Network: The signaling
overhead in the network is not reduced by HMIPv6, as mentioned in
Section 8.2. Instead, FMIPv6 generates extra signaling overhead
between the previous access router and new access router for
HI/HAck exchange. For payload data, the same considerations as for
Goal #4 are applicable.

Goal #6 Security Between Mobile Node and Network: FMIPv6 requires
the mobile node and the previous access router to share a security
association in order to secure the FBU/FBA exchange. In addition,
HMIPv6 requires that the mobile node and MAP share an IPsec
security association in order to secure LBU/LBA exchange. The only
well understood approach to set up an IPsec security association is
the use of certificates, but this may raise deployment issues.
Thus, the combination of FMIPv6 and HMIPv6 doubles the amount of
mobile node to network security protocol required, since security
for both FMIP and HMIP must be deployed.

Goal #7 Support for Heterogeneous Wireless Link Technologies:
HMIPv6 and FMIPv6 support multiple wireless technologies, so this
goal is fufilled.

Goal #8 Support for Unmodified Mobile Nodes: The mobile node must
support both HMIPv6 and FMIPv6 protocols, so this goal is not
fulfilled.

Goal #9 Support for IPv4 and IPv6: Currently there is no IPv4
version of HMIPv6. There is an IPv4 version of FMIP but it is not
clear how it could be used together with FMIPv6 in order to handle
fast handovers across any wired network.

Goal #10 Re-use of Existing Protocols Where Sensible: This
solution re-uses existing protocols, HMIPv6 and FMIPv6.

8.4 Micromobility Protocols

Researchers have defined some protocols that are often
characterized as micromobility protocols. Two typical protocols in
this category are Cellular-IP [2] and HAWAII [16]. Researchers
defined these protocols before local mobility optimizations for
Mobile IP such as FMIP and HMIP were developed, in order to reduce
handover latency. Cellular-IP and HAWAII were proposed in the IETF
for standardization, but after some study in the IRTF, were
dropped. There are many micromobility protocols defined in the
academic literature, but in this document, the term is used
specifically to refer to Cellular-IP and HAWAII.

The micromobility approach to localized mobility management
requires host route propagation from the mobile node to a
collection of specialized routers in the localized mobility
management domain along a path back to a boundary router at the
edge of the localized mobility management domain. A boundary router
is a kind of localized mobility management domain gateway.
Localized mobility management is authorized with the access router,
but reauthorization with each new access router is necessary on
link movement, in addition to any reauthorization for basic network
access. The host routes allow the mobile node to maintain the same
IP address when it moves to a new link, and still continue to
receive packets on the new link.

Cellular IP and HAWAII have a few things in common. Both are
compatible with Mobile IP and are intended to provide a higher
level of handover performance in local networks than was previously
available with Mobile IP without such extensions as HMIP and FMIP.
Both use host routes installed in a number of routers within a
restricted routing domain. Both define specific messaging to update
those routes along the forwarding path and specify how the
messaging is to be used to update the routing tables and forwarding
tables along the path between the mobile and a micromobility domain
boundary router at which point Mobile IP is to used to handle
global mobility in a scalable way. Unlike the FMIP and HMIP
protocols, however, these protocols do not require the mobile node
to obtain a new care of address on each access router as it moves;
but rather, the mobile node maintains the same care of address
across the micromobility domain. From outside the micromobility
domain, the care of address is routed using traditional longest
prefix matching IP routing to the domain's boundary router, so the
care of address is conceptually withain the micromobility domain
boundary router's subnet. Within the micromobility domain, the care
of address is routed to the correct access router using host
routes.

Micromobility protocols have some potential drawbacks from a
deployment and scalability standpoint. Both protocols involve every
routing element between the mobile device and the micromobility
domain boundary router in all packet forwarding decisions specific
to care of addresses for mobile nodes. Scalability is limited
because each care of address corresponding to a mobile node
generates a routing table entry, and perhaps multiple forwarding
table entries, in every router along the path. Since mobile nodes
can have multiple global care of addresses in IPv6, this can result
in a large expansion in router state throughout the micromobility
routing domain. Although the extent of the scalability for
micromobility protocols is still not clearly understood from a
research standpoint, it seems certain that they will be less
scalable than the Mobile IP optimization enhancements, and will
require more specialized gear in the wired network.

The following is a gap analysis of the micromobility protocols
against the goals in Section 2.0:

Goal #1 Handover Performance Improvement: The micromobility
protocols reduce handover latency by quickly fixing up routes
between the boundary router and the access router. While some
additional latency may be expected during host route propagation,
it is typically much less than experienced with standard Mobile IP.

Goal #2 Reduction in Handover-related Signaling Volume: The
micromobility protocols require signaling from the mobile node to
the access router to initiate the host route propagation, but that
is a considerable reduction over the amount of signaling required
to configure to a new link.

Goal #3 Location privacy: No care of address changes are exposed to
correspondent nodes or the mobile node itself while the mobile node
is moving in the micromobility-managed network.

Goal #4 Use of Wireless Resources: The only additional over-the-air
signaling is involved in propagating host routes from the mobile
node to the network upon movement. Since this signaling would be
required for movement detection in any case, it is expected to be
minimal. Mobile node traffic experiences no overhead.

Goal #5 Limit the Signaling Overhead in the Network: Host route
propagation is required throughout the wired network. The volume of
signaling could be more or less depending on the speed of mobile
node movement and the size of the wired network.

Goal #6 Security Between Mobile Node and Network: The mobile node
only requires a security association of some type with the access
router. Because the signaling is causing routes to the mobile
node's care of address to change, the signaling must prove
authorization to hold the address.

Goal #7 Support for Heterogeneous Wireless Link Technologies:
HMIPv6 The micromobility protocols support multiple wireless
technologies, so this goal is satisfied.

Goal #8 Support for Unmodified Mobile Nodes: The mobile node must
support some way of signaling the access router on link handover,
but this is required for movement detection anyway. The nature of
the signaling for the micromobility protocols may require mobile
node software changes, however.

Goal #9 Re-use of Existing Protocols Where Sensible: Support for
IPv4 and IPv6: Most of the work on the micromobility protocols was
done in IPv4, but little difference could be expected for IPv6.

Goal #10 This solution does not reuse an existing protocol because
there is currently no Internet Standard protocol for micromobility.

Goal #11 Localized Mobility Management Independent of Global
Mobility Management: This solution separates global and local
mobility management, since the micromobility protocols only support
localized mobility management.

8.5 Summary

The following table summarizes the discussion in Section 9.1
through 9.5. In the table, a "M" indicates that the protocol
completely meets the goal, a "P" indicates that it partially meets
the goal, and an "X" indicates that it does not meet the goal.

Protocol #1 #2 #3 #4 #5 #6 #7 #8 #9 #10
-------- -- -- -- -- -- -- -- -- -- ---

MIPv6 P X X X X X M X M M
HMIPv6 P X X X P X M X X M

MIPv6 +
FMIPv6 M X X X P X M X P M

HMIPv6 +
FMIPv6 M X X X X X M X X M

Micro. M M M M P M M M P X

9.0

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