INTERNET-DRAFT Carl Williams, Editor
Internet Engineering Task Force MCSR Labs
Issued: October 2003
Expires: April 2004
Localized Mobility Management Requirements
<draft-ietf-mobileip-lmm-requirements-04.txt>
Status of This Memo
This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC 2026.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas and its working groups. Note that
other groups may also distribute working documents as Internet-
Drafts.
Internet-Drafts are draft documents valid for a maximum of six
months and may be updated, replaced, or obsoleted by other documents
at any time. It is inappropriate to use Internet-Drafts as
reference material or to cite them other than as 'work in progress.'
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.
Abstract
This document describes requirements for Localized Mobility
Management (LMM) for Mobile IP and Mobile IPv6 protocols.
These requirements are intended to guide the design of a protocol
specification for LMM. Localized Mobility Management, in general,
introduces enhancements to Mobile IPv4 and Mobile IPv6 to
reduce the amount of latency in binding updates sent to the Home
Agent and, for route-optimization, Correspondent Nodes, upon
Care of Address change. In addition, LMM seeks to reduce the
amount of signaling over the global Internet when a mobile
node traverses within a defined local domain. The identified
requirements are essential for localized mobility management
functionality. They are intended to be used as a guide for
analysis on the observed benefits over the identified requirements
for architecting and deploying LMM schemes.
Carl Williams, Editor Expires April 2004 [Page 1]
INTERNET DRAFT Localized Mobility Management Requirements October 2003
Table of Contents
1.0 Introduction .................................................... 2
2.0 Terminology ..................................................... 4
3.0 Requirements .................................................... 4
3.1 Intra-domain mobility ........................................ 4
3.2 Security ..................................................... 4
3.3 Induced LMM functional requirement ........................... 5
3.4 Scalability, Reliability, and Performance .................... 5
3.5 Mobility Management Support .................................. 7
3.6 Auto-configuration capabilities for LMM constituents.......... 7
3.7 LMM Inter-working with IP routing infrastructure requirement.. 8
3.8 Sparse routing element population requirement ................ 8
3.9 Support for Mobile IPv4 or Mobile IPv6 Handover .............. 8
3.10 Simple network design requirement ........................... 8
3.11 Stability ................................................... 9
3.12 QoS Requirements ............................................ 9
4.0 Security Considerations ......................................... 9
5.0 Acknowledgments ................................................. 9
6.0 References ...................................................... 9
Appendix A û LMM Requirements and HMIPv6............................. 11
Author's Addresses .................................................. 11
Full Copyright Statement ............................................ 11
1.0 Introduction
In order to meet the demands of real-time applications and the expectations
of future wireless users for service level quality similar to the one of
wireline users, IP based mobility management is facing a number of technical
challenges in terms of performance and scalability [4, 5, 6]. These manifest
themselves as increased latencies in the control signaling between a Mobile
Node and its peer entities, namely the Home Agent (HA) and its Corresponding
Nodes (CNs).
In the base Mobile IP protocol [3], movement between two subnets
requires that the Mobile Node obtain a new Care of Address in the
new subnet. This allows the Mobile Node to receive traffic on the
new subnet. In order for the routing change to become effective,
however, the Mobile Node must issue a binding update (also known in
Mobile IPv4 as a Home Agent registration) to the Home Agent so that
the Home Agent can change the routing from the previous subnet to
the new subnet. The binding update establishes a host route on the
Home Agent between the Mobile Node's Home Address and its new Care
of Address. In addition, if route optimization is in use [3], the
Mobile Node may also issue binding updates to Correspondent Nodes to
allow them to send traffic directly to the new Care of Address
rather than tunneling their traffic through the Home Agent.
Traffic destined for the Mobile Node is sent to the old Care of
Address and is, effectively, dropped until the Home Agent processes
the MIPv6 Binding Update or MIPv4 Home Agent Registration. If the
Mobile Node is at some geographical and topological distance away
Carl Williams, Editor Expires April 2004 [Page 2]
INTERNET DRAFT Localized Mobility Management Requirements October 2003
from the Home Agent and Correspondent Nodes, the amount of time
involved in sending the binding updates may be greater than 100
hundred milliseconds. This latency in routing update may cause
some packets for the Mobile Node to be lost at the old Access Router.
Recently, Mobile IP has been extended by certain local mobility mechanisms,
aiming to alleviate the above performance limitations; they are identified
as hierarchical/regional or more generically Localized Mobility Management
(LMM). LMM schemes allow the Mobile Node to continue receiving traffic on
the new subnet without any change in the Home Agent or Correspondent
Node binding. The latency involved in updating the Care of Address bindings
at far geographical and topological distances is eliminated or reduced until
such time as the Mobile Node is in a position to manage the latency cost.
Having provided some motivation and brief summary of the underlying
principles of LMM, it is important to enumerate goals for LMM.
Goals for LMM:
- reduce the signaling induced by changes in the
point of attachment due to the movement of a host;
reduction in signaling delay will minimize
packet loss and possible session loss;
- reduce the usage of air-interface and network
resources for mobility;
- reduce the processing overhead at the peer nodes,
thereby improving protocol scalability;
- avoid or minimize the changes of, or impact to the
Mobile Node, Home Agent or the Correspondent Node;
- avoid creating single points of failure;
- simplify the network design and provisioning
for enabling LMM capability in a network;
- allow progressive LMM deployment capabilities.
Identifying a solid set of requirements that will render the
protocol internals, for some LMM scheme, robust enough to
cater for the aforementioned considerations becomes essential
in designing a widely accepted solution. The remainder of this
document present a set of requirements that encompass essential
considerations for the design of an LMM scheme. It is with this
foundation that we can seek to ensure that the resulting LMM
solution will best preserve the fundamental philosophies and
architectural principles of the Internet in practice today.
Carl Williams, Editor Expires April 2004 [Page 3]
INTERNET DRAFT Localized Mobility Management Requirements October 2003
2.0 Terminology
Please also see [7] for mobility terminology used in this document.
3.0 LMM Requirements
This section describes the requirements for a LMM solution. The
requirements are relevant to both Mobile IPv4 and Mobile IPv6.
3.1 Intra-domain mobility
LMM is introduced to minimize the signaling traffic to the Home Agent
and/or Correspondent Node(s) for intra-domain mobility (within a
Local Coverage Area). This is the fundamental reason for
introducing localized mobility management extensions to core Mobile
IPv6.
In the LMM infrastructure a Correspondent Node or Home Agent outside
the administration domain MUST always be able to address the mobile
host by the same IP address, so that from the point of view of hosts
outside the administration domain, the IP address of the mobile host
remains fixed regardless of any changes in the Mobile Node's subnet.
3.2 Security
3.2.1 LMM protocol MUST provide for "security provisioning" within the
respective local coverage area.
The security of exchanging LMM specific information and signaling MUST
be ensured. Security provisioning includes protecting the integrity,
confidentiality, and authenticity of the transfer of LMM specific
information within the administration domain. If applicable, replay
protection MUST exist mutually between the LMM agents.
3.2.2 LMM protocol MUST NOT interfere with the security provisioning that
exists between the Home Agent and the Mobile Node.
3.2.3 LMM protocol MUST NOT interfere with the security provisioning that
exists between the Correspondent Node and the Mobile Node.
3.2.4 LMM protocol MUST NOT introduce new security holes or the possibility
for DOS-style attacks.
Carl Williams, Editor Expires April 2004 [Page 4]
INTERNET DRAFT Localized Mobility Management Requirements October 2003
3.3 Induced LMM functional requirements
3.3.1 Any Localized Mobility Management protocol MUST NOT inject
any additional functionality over base Mobility [2, 3] at the
Home Agent or any of its peer CNs. Thus, the LMM framework
MUST NOT add any modifications or extensions to the Correspondent
Node(s) and Home Agent. It is essential to minimize
the involvement of the Mobile Node in routing beyond what is in
the basic MIP and MIpv6 protocol. Preferences, load balancing, and
other complex schemes requiring heavy mobile node involvement
in the mobility management task SHOULD BE avoided.
3.3.2 Non-LMM-aware routers, hosts, Home Agents, and Mobile Nodes
MUST be able to interoperate with LMM agents.
3.3.3 The LMM framework MUST NOT increase the number of messages between
the mobile host and the respective Correspondent Node(s) and Home
Agent. Indeed, the LMM framework MUST minimize the global
signaling between the MN and its peers. The amount
of regional signaling MUST NOT surpass the amount of global
signaling that would have otherwise occurred if LMM were not
present.
3.4 Scalability, Reliability, and Performance
3.4.1 The LMM complexity MUST increase at most linearly with the
size of the local domain and the number of Mobile Nodes.
3.4.2 Any Localized Mobility Management protocol MUST assure that
that LMM routing state scales at most linearly with the number
of Mobile Nodes registered, and that the increase in routing
state is confined to those ARs/ANRs involved in implementing
the LMM protocol at hand. This would involve MIP-specific
routing state as binding caches in addition to standard
routing table host routes. While host routes cannot be
eliminated by any mobility management protocol including
base IP mobility, any LMM protocol MUST keep the number of
host routes to a minimum.
Carl Williams, Editor Expires April 2004 [Page 5]
INTERNET DRAFT Localized Mobility Management Requirements October 2003
3.4.3 The LMM framework MUST NOT introduce additional points of failure in
the network. The current access router would be excluded from
this requirement.
3.4.4 The LMM framework MUST NOT interfere with the basic IP mobility
performance of a mobile host communications with a Correspondent
Node(s).
3.4.5 Scalable expansion of the network
The LMM framework MUST allow for scalable expansion of the network
and provide for reasonable network configuration with regard
to peering, inter-administrative domain connectivity, and other
inter-administrative domain interoperability characteristics of
interest to wireless ISPs. The LMM framework MUST NOT introduce
any additional restrictions in how wireless ISPs configure their
network, nor how they interconnect with other networks beyond
those introduced by standard IP routing. In addition, the
amount of regional signaling MUST NOT increase as the Local
Domain expands in size.
3.4.6 Resilience to topological changes
The LMM protocols MUST be topology-independent. The LMM protocols
MUST be able to adapt to topological changes within the domain. The
topological changes may include the addition or removal/failure of
LMM agents or that of changes in the routing of the local domain
over which the LMM scheme is applied.
3.4.7 Header or Tunneling overhead
The LMM framework MUST not prevent header compression from being applied.
It is recommended that andidate LMM designs that require additional header
overhead for tunnel be reviewed by the ROHC working group to determine if
the header compressor can be restarted from transferred compressor context
when handover occurs without requiring any full header packet exchange on
the new link.
Carl Williams, Editor Expires April 2004 [Page 6]
INTERNET DRAFT Localized Mobility Management Requirements October 2003
3.4.8 Optimized signaling within the Local Coverage Area
By its very nature, LMM reintroduces triangle routing into Mobile IPv6
in that all traffic must go through the LMM agent. There is no way
to avoid this. The LMM framework SHOULD be designed in such a way
as to reduce the length of the unwanted triangle leg.
The LMM design SHOULD not prohibit optimal placement of LMM agents to
reduce or eliminate additional triangle routing introduced by LMM.
NOTE: It is not required that a LMM scheme specify LMM agents as part
of its solution.
3.5 Mobility Management Support
The following LMM requirements pertain to both inter-domain and
intra-domain hand-off.
3.5.1 The LMM framework MUST NOT increase the amount of latency or amount of
packet loss that exists with the core Mobile IP and Mobile IPv6
specification [2, 3]. Indeed, the LMM framework SHOULD decrease the
amount of latency or amount of packet loss that exists with the
core mobility protocols.
3.5.2 The LMM framework MUST NOT increase the amount of service disruption
that already exists with the core mobility specifications.
Again, the LMM framework SHOULD decrease the amount of service
disruption that already exists with the core mobility protocols.
3.5.3 The LMM framework MUST NOT increase the number of messages between
the mobile host and the respective Correspondent Node(s) and Home
Agent as is in the core mobility specifications [2, 3]. The LMM
framework SHOULD decrease the number of messages between the
mobile host and the respective Correspondent Node(s) and Home
Agent as is in the core mobility specifications [2, 3].
3.6 Auto-configuration capabilities for LMM constituents
It is desirable that in order to allow for simple incremental
deployment of an LMM scheme, the local mobility agents MUST
require minimal (if any) manual configuration. This plug-and-play
feature could make use of IPv6 auto-configuration mechanisms in
the case of Mobile IPv6 [3], even though most likely other
automatic configurations will be needed (such as, for example,
learning about adjacent LMM agents). Auto-configuration also
facilitates the network to dynamically adapt to general topological
changes (whether planned or due to link or node failures).
Carl Williams, Editor Expires April 2004 [Page 7]
INTERNET DRAFT Localized Mobility Management Requirements October 2003
3.7 LMM inter-working with IP routing infrastructure requirement
The LMM framework MUST NOT disrupt core IP routing outside
the local domain.
3.8 Sparse routing element population requirement
Any LMM protocol MUST be designed to be geared towards
incremental deployment capabilities; the latter implies
that the LMM scheme itself imposes minimum requirements
on the carrierÆs network. Incremental deployment capabilities
for an LMM protocol signifies that an initial set of sparse
LMM agents can populate the administration domain of a network
provider and operate sufficiently. In addition, any LMM
scheme MUST be compatible with any additional deployment
of LMM agents in future infrastructure expansions; that is to
say, allow progressive LMM deployment capabilities.
It is for this reason that the LMM framework MUST NOT require
that all routing elements be assumed to be LMM-aware in the
signaling interactions of an LMM protocol. The LMM framework
MUST BE supported, at the very minimum, by a sparse (proper
subset) LMM agent population that is co-located within the
routing topology of a single administration domain.
3.9 Support for Mobile IPv4 or Mobile IPv6 Handover
Since one of the primary goals of LMM is to minimize
signaling during handover, an LMM solution MUST be
available for the standardized Mobile IPv4 or Mobile IPv6
handover algorithms. LMM and the Mobile IP or Mobile IPv6
handover algorithms MUST maintain compatibility in their
signaling interactions for fulfilling complementary roles
with respect to each other.
This requirement SHOULD NOT be interpreted as ruling out
useful optimizations of LMM and Mobile IP or Mobile IPv6 handoff
schemes that simplify the implementation or deployment of LMM or
Mobile IP or Mobile IPv6 handoff.
3.10 Simple Network design requirement
LMM SHOULD simplify the network design and provisioning for enabling LMM
capability in a network and allow progressive LMM deployment capabilities.
Carl Williams, Editor Expires April 2004 [Page 8]
INTERNET Draft Localized Mobility Management Requirements October 2003
3.11 Stability
LMM MUST avoid any forwarding loops.
3.12 Quality of Service requirements
3.12.1 The LMM MUST have the ability to coexist with
QoS schemes to hide the mobility of the MN to its peer
by avoiding end-to-end QoS signaling.
3.12.2 The LMM MUST have the ability to coexist with QoS
schemes to facilitate the new provisioning of both uplink
and downlink QoS after a handoff.
4.0 Security Considerations
This document does not generate any additional security considerations.
5.0 Acknowledgments
Thank you to all who participated in the LMM requirement discussion
on the Mobile IP working group alias. First, the editor wishes to recognize
Theo Pagtzis's work on LMM requirement analysis. Theo has contributed
significantly to the LMM discussion on the mailing list and at IETF
working group meetings and has provided text for various requirements.
Special thanks also to Gabriel Montenegro, John Loughney, Alper Yegin, Alberto
Lopez Toledo, and Madjid Nakhjiri for providing input to the draft in its
preliminary stage and many other comments they had.
Thanks to the LMM requirement analysis design team: Hesham Soliman, Erik
Nordmark, Theo Pagtzis, James Kempf, and Jari Malinen.
Additional comments on the LMM requirements were received from: Charlie
Perkins, Muhammad Jaseemuddin, Tom Weckstr, Jim Bound, Gopal Dommety,
Glenn Morrow, Arthur Ross, Samita Chakrabarti, Karim El-Malki, Phil Neumiller,
Behcet Sarikaya, Karann Chew, Michael Thomas, Pat Calhoun, Bill Gage, Vinod
Choyi, John Loughney, Wolfgang Schoenfeld, David Martin, Daichi Funato, Ichiro
Okajima, Jari Malinen, Kacheong Poon, Koshimi Takashi, and Cedric Westphal.
An LMM requirement analysis of this body of work was completed by a number
of members of the Mobile IP working group and published in [1] below.
In addition special thanks to the Mobile IP working group chairs,
Phil Roberts, Gabriel Montengro, and Basavaraj Patil, for their input as
well as capturing/organizing the initial set of requirements from the
discussions.
Carl Williams, Editor Expires April 2004 [Page 9]
INTERNET DRAFT Localized Mobility Management Requirements October 2003
6.0 References
Normative References
[1] T. Pagtzis, C. Williams, P. Kirstein, C. Perkins and
A. Yegin, "Requirements for Localised IP Mobility
Management", Proceedings of IEEE Wireless Communications
and Networking Conference (WCNC2003), Louisiana,
New Orleans, March 2003.
[2] Perkins, C., "IP Mobility Support for IPv4,"
RFC3344, August 2002.
[3] David B. Johnson, Charles Perkins, J. Arkko,
"Mobility Support in IPv6", Work in Progress, June 2003.
[4] G. Karlsson, ôQuality Requirements for Multimedia Network
Servicesö, Proceedings of Radiovetenskap ach kommunikation,
June 1996, pp. 96-100.
[5] T. Kurita, S. Iai, and N. Kitawaki, ôEffects of transmission
delay in audiovisual communicationsö, Electronics and
Communications in Japan, Vol 77, no 3, pp. 63-74, 1995.
[6] Y. Wang, M. Claypool, and Z. Zuo, ôAn Empirical Study of
RealVideo Performance Across the Internetö, in Proceedings of
ACM SIGCOMM Internet Measurement Workshop, Nov. 2001.
[7] J. Manner, M. Kojo, ôMobility Related Terminologyö,
Work in Progress, April 2003.
Informative References
[8] R. Koodli. (Editor), "Fast Handovers for Mobile
IPv6"; Work in Progress; October 2003.
[9] Soliman, H., Castelluccia, C., El-Malki, K., Bellier L.,
ôHierarchical Mobile Ipv6 mobility management (HMIPv6)ö,
Work in progress, June 2003.
Carl Williams, Editor Expires April 2004 [Page 10]
INTERNET DRAFT Localized Mobility Management Requirements October 2003
Appendix A - LMM requirements and HMIPv6
HMIPv6 was evaluated as a localized mobility management protocol, and that it
was mostly found to satisfy the requirements put forth in this document. This
section details one exception with some explanation.
Exception 1:
One LMM requirement that needs further clarification with respect to HMIPv6 is
the requirement that states that LMM should not introduce additional single
points of failure. The HMIPv6 Mobility Anchor Point (MAP) is a new single
point of failure. Proposals for HMIPv6 MAP replication can be optionally
incorporated in order to avoid this new single point of failure. Such proposals
can also be applied to the base Mobile IPv6 specification to also allow for Home
Agent failover as well.
Author Address
Carl Williams
MCSR Labs
3790 El Camino Real
Palo ALto, CA 94306 USA
phone: +1 650 279 5903
email: carlw@mcsr-labs.org
Full Copyright Statement
Copyright (C) The Internet Society (2000). All Rights Reserved.
This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any
kind, provided that the above copyright notice and this paragraph
are included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for
copyrights defined in the Internet Standards process must be
followed, or as required to translate it into languages other than
English.
The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assigns.
This document and the information contained herein is provided on an
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Carl Williams, Editor Expires April 2004 [Page 11]
