Network-based Localized Mobility Management BOF (netlmm)

xxxxxx, November 1 at xxxx-xxxx
=============================

CHAIRS:  James Kempf <kempf@docomolabs-usa.com>
         Phil Roberts <Phil.Roberts@motorola.com>

DESCRIPTION:

There is considerable evidence that mobility for IP hosts 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 Mobile IP hosts, and 
the protocols developed have required host-side support at the IP 
layer. Recently in the IETF, new work on global mobility management 
approaches other than Mobile IP 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 host involvement, have 
seen widespread deployment, indicating the technical feasibility 
and positive user acceptance of this approach. This suggests a 
possible design paradigm that could be used to accommodate global 
mobility management protocols of different types while reducing 
host software complexity and expanding the range of hosts that 
could be accommodated: a network-based, localized mobility protocol 
with no host software required specifically for localized mobility 
management and no requirement for a network interface to change IP 
address when it 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 wired network maintain a collection of routes for individual 
hosts. The routes point to the access routers on which mobile hosts 
currently are located. Packets for the mobile host are routed to and 
from the hosts through the mobility anchor point. When a host moves 
from one access router to another, the access routers send a route 
update to the mobility anchor point. While some host involvement is 
necessary and expected for generic mobility functions such as movement 
detection and to inform the access router about host movement, no 
specific host to network protocol will be required for localized 
mobility management. 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 host that powers on or moves from another 
  localized mobility management domain, or an existing mobile host 
  that shuts down without any notice (i.e. crashes),
- Handles routing update when a mobile host 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 must work across multiple different kinds 
of wired and wireless backbone network link layer types. The protocol 
itself will be agnostic with respect to the last hop link layer 
protocol between the host 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 host. This will enable the access router 
to do a route update using NETLMM on behalf of the host. In addition 
to the NETLMM protocol document, the Working Group will produce an 
informational document that describes how existing and developing 
IETF standards for host 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, 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 host. 
Security will be defined for the protocol based on standard IETF 
security protocols, but should maintain configuration flexibility 
for varying deployment circumstances. 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 NEMO, DNS, 
DNA, and global mobility protocols such as Mobile IP.

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 drills down in more detail on 
  the required properties for a protocol solution and why existing 
  IETF protocols are insufficient,
- A protocol design for an interoperable, scalable network-based
  localized mobility management protocol between the access routers 
  and the mobility anchor point,
- A document describing how existing or developing IETF protocol
  standards can be used between the access router and the host to 
  inform the access router about the arrival of a host, for use when 
  the wireless link protocol does not provide support for this function.

This document will also discuss the issue of secure host 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.

Schedule
--------
Nov. 2005 - IETF 64, Charter Working Group.

Feb. 2006 - Working Group Last Call on Problem Statement and Requirements
drafts.

March 2006 - IETF 65, Discuss Last Call comments on Problem Statement and
Requirements drafts.

April 2006 - Submit Problem Statement and Requirements drafts to IESG for
publication as Informational RFCs.

June 2006 - Working Group Last Call on Protocol draft. Working Group Last
Call on host to access router draft.

Aug. 2006 - IETF 66, Discuss Last Call comments on Protocol draft.

Nov. 2006 - IETF 67, Submit Protocol draft for publication as Proposed
Standard. Submit host to access router draft as Informational.

Dec. 2006 - Recharter to address enhancements

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