Subject: WG Action: Network-based Localized Mobility Management (netlmm)

From: IESG Secretary <[email-masked]>
Date: Wed, 11 Jan 2006 16:51:49 -0500

A new IETF working group has been formed in the Internet Area.  For
additional information, please contact the Area Directors or the WG Chairs.

+++

Network-based Localized Mobility Management (netlmm)
=====================================================

Current Status: Active Working Group

Chair(s):
Phil Roberts <[email-masked]>
James Kempf <[email-masked]>

Internet Area Director(s):
Mark Townsley <[email-masked]>
Margaret Wasserman <[email-masked]>

Internet Area Advisor:
Margaret Wasserman <[email-masked]>

Mailing Lists:
General Discussion: [email-masked]
To Subscribe: https://vesuvio.ipv6.cselt.it/mailman/listinfo/netlmm to subscribe
Archive: 

Description of Working Group:
There is considerable evidence that mobility for IP nodes can be more
efficiently handled if mobility management is broken down into 
localized mobility management and global mobility management. Local 
mobility involves movements across some administratively and 
geographically contiguous set of subnets, while global mobility 
involves movements across broader administrative, geographical, 
and topological domains. Previous work in the IETF has focused on
supporting localized mobility management for a Mobile IPv6 node, and 
the protocols developed have required mobile node-side support at the 
IP layer. Recently in the IETF, new work on global mobility 
management approaches other than Mobile IPv6 suggests that a localized
mobility management approach decoupled from the global mobility 
management protocol might result in a more modular mobility management 
system design and therefore more longevity and an easier evolution 
path. In the WLAN infrastructure market, WLAN switches, which perform 
localized mobility management without any mobile node involvement, have
seen widespread deployment, indicating the technical feasibility and 
positive user acceptance of this approach. This suggests a design 
paradigm that could be used to accommodate global mobility management 
protocols of different types while not increasing software complexity: 
a network-based, localized mobility protocol with no mobile node 
software to specifically implement localized mobility management
and no requirement for a network interface to change IP address when 
the mobile node changes to a new router. The task of the NETLMM Working
Group is to design a protocol solution for network-based localized 
mobility management.

The network-based localized mobility management protocol will conform 
to the following framework. Mobility anchor points within the backbone 
network maintain a collection of routes for individual mobile nodes. 
The routes point to the access routers on which mobile nodes currently 
are located. Packets for the mobile node are routed to and from the 
mobile node through the mobility anchor point. When a mobile node 
moves from one access router to another, the access routers send a 
route update to the mobility anchor point. While some mobile node 
involvement is necessary and expected for generic mobility functions
such as movement detection and to inform the access router about 
mobile node movement, no specific mobile node to network protocol will 
be required for localized mobility management itself. The working 
group will develop a protocol between the access routers and mobility 
anchor points that minimally has the following functions:

- Handles a new mobile node that powers on or moves from another
localized mobility management domain, or an existing mobile node that 
shuts down without any notice (i.e. crashes), 

- Handles routing update when a mobile node moves from one access
router to another within the localized mobility management domain,

The necessity for additional protocol functions may arise during 
Working Group discussions, so this list should not be taken as final. 

The protocol will be independent of any particular global mobility
management protocol, and it will be link-layer agnostic by running on 
top of IP. The protocol itself will be agnostic with respect to the 
last hop link layer protocol between the mobile node and the access 
router. Adaptation of the protocol to different kinds of last hop link 
layers is accomplished through an interface on the access router 
common to all link layers under which specific link layer mechanisms 
(possibly together with authentication mechanisms) can provide a
reliable handover indication and unique identity for the mobile node. 
This will enable the access router to do a route update using NETLMM
on behalf of the mobile node. In addition to the NETLMM protocol
document, the Working Group will produce an informational document 
that describes how existing and developing IETF standards for node to 
access router communication on the local link can be used to accomplish
secure triggering of route update. This document will be informational 
only, because some link protocols are expected to provide their own 
mechanisms. 

The scope of the work is initially limited to IPv6 both in the backbone
and on the edges, and is primarily for networks covering larger 
geographical regions such as multiple corporate campuses and 
metropolitian areas. The protocol will not attempt to hide handover 
between two separate interfaces on the mobile node. The protocol will 
not define a new tunneling protocol but will reuse existing IP 
tunneling mechanisms if necessary. The NETLMM protocol will maintain 
compatibility with other IETF standards, both existing and developing, 
such as DNS, DNA, and global mobility protocols such as Mobile IPv6 
and NEMO Basic Support.

Security between access routers and the mobility anchor will be defined
for the protocol based on an IETF-approved threat model giving 
preference to existing security solutions where applicable. The threat 
model will be described in a document delivered sufficiently in 
advance of completion of the protocol design that the protocol design 
can accommodate mitigation measures. In addition, the mobile node to
router interface document will describe threats to the protocol when 
the default, IP-level mobile node to router protocol is used, and will 
prescribe how existing security protocols are used to counter the 
threats.

The Working Group has the following deliverables:

- A problem statement document that clearly and succinctly describes
the problem posed by localized mobility management and why a 
network-based approach is desirable,
- A requirements and gap analysis that examines a selection of 
existing IETF protocols, particularly within the mobility space, for 
applicability as a solution. If a proposed protocol is insufficient as 
a solution, the reasons why will be clearly stated.
- A threat model draft that describes the threats to a netlmm
protocol, based on the framework described in this charter, and how 
the threats can be mitigated giving preference to existing security 
solutions where applicable.
- A protocol design for an interoperable, scalable network-based
localized mobility management protocol between the access routers and 
the mobility anchor point including security for the access router to 
mobility anchor interface, 
- A document describing how existing or developing IETF protocol
standards can be used between the access router and the mobile node to 
inform the access router about the arrival of a mobile node, for use 
when the wireless link protocol does not provide support for this 
function. This document will also discuss threats and security
countermeasures for mobile node identification.

Out of scope for the first design are: route optimization, inter-access
router tunneling to optimize handover, mechanisms for handover between 
localized mobility management domains (other than standard global 
mobility management protocols), IPv4 support, and multiple mobility 
anchor points. During the design process, these enhancements will be 
kept in mind, but actual work to incorporate them or other 
enhancements will be deferred until after the initial design is 
complete and the working group recharters.

Goals and Milestones:
Jan 2006    Charter Working Group  
Mar 2006    Working Group Last Call on Problem Statement and Requirements documents  
Mar 2006    IETF 65, Discuss Last Call comments on Problem Statement and Requirements documents  
Apr 2006    Submit Problem Statement and Requirements documents to IESG for publication as Informational RFCs  
Jun 2006    Working Group Last Call on Threat Model documents. Submit Threat Model document to SAAG for review  
Jul 2006    Working Group Last Call on Threat Model document  
Aug 2006    IETF 66, Discuss Last Call comments on Threat Model document  
Sep 2006    Submit Threat Model document to IESG for publication as an Informational RFC  
Oct 2006    Working Group Last Call on Protocol draft. Working Group Last Call on Mobile Node to Access Router document  
Nov 2006    IETF 67, Discuss last call comments on Protocol document and Mobile Node toAccess Router document  
Dec 2006    Submit Protocol draft to IESG for publication as Proposed Standard and Mobile Node to Access Router document for publication as Informational  
Jan 2007    Recharter to address enhancements

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