2.7.1 Interim Meeting - Mobility EXTensions for IPv6 (mext)

NOTE: This charter is a snapshot of the 71st IETF Meeting in Philadelphia, PA USA. It may now be out-of-date.

Last Modified: 2007-11-26


Marcelo Bagnulo <marcelo@it.uc3m.es>
Julien Laganier <julien.ietf@laposte.net>

Internet Area Director(s):

Jari Arkko <jari.arkko@piuha.net>
Mark Townsley <townsley@cisco.com>

Internet Area Advisor:

Jari Arkko <jari.arkko@piuha.net>

Mailing Lists:

General Discussion: mext@ietf.org
To Subscribe: https://www1.ietf.org/mailman/listinfo/mext
Archive: http://www1.ietf.org/mail-archive/web/mext/current

Description of Working Group:

Mobile IPv6 specifies routing support which permits an IPv6 host to
continue using its home address as it moves around the Internet,
enabling continuity of sessions. Mobile IPv6 supports transparency
above the IP layer, including maintenance of active transport level
sessions. In addition, network mobility (NEMO) mechanisms built on top
of Mobile IPv6 allow managing the mobility of an entire network, as it
changes its point of attachment to the Internet. The base
specifications consist of:

o RFC 3775 (Mobile IPv6)
o RFC 3963 (NEMO)
o RFC 4877 (Mobile IPv6 Operation with IKEv2)

The MEXT Working Group continues the work of the former MIP6, NEMO,
and MONAMI6 Working Groups.

The primary goal of MEXT will be to (A) enhance base IPv6 mobility by
continuing work on developments that are required for wide-scale
deployments and specific deployment scenarios. Additionally, (B) the
working group will ensure that any issues identified by implementation
and interoperability experience are addressed, and that the base
specifications are maintained. (C) The group will also produce
informational documentation, such as design rationale documents or
description of specific issues within the protocol.

Deployment considerations call for (A.1) solutions to enable
dual-stack operation, (A.2) mechanisms to support high-availability
home agents, (A.3) allowing the use of multiple interfaces in mobile
nodes, (A.4) ways to employ Mobile IPv6 in the presence of firewalls,
(A.5) address the specific needs of automotive and aviation
communities for route optimisation in network mobility, and (A.6)
support for AAA is needed as a continuation of earlier work on

Work items related to large scale deployment include:

(A.1) A Solution for Mobile IPv6 and NEMO session continuity for dual
stack hosts which attach to IPv4 access networks. Additionally
provide a mechanism for carrying IPv4 packets via the Home agent
for Mobile IPv6 or NEMO capable dual-stack hosts.

(A.2) A protocol based solution for enhancing the reliability of home
agents and a method to force a host/router to switch home agents.

A mechanism to force an MN to switch the HA that is currently
serving it. This is required in deployments where the HA needs to
be taken offline for maintenance.

(A.3) Use of multiple interfaces.

Today, the protocols do not provide suppport for simultaneous
differentiated use of multiple access technologies. Several
proposals exist for such support, and some of them have been
implemented and tested.

When a mobile host/router uses multiple network interfaces
simultaneously, or when multiple prefixes are available on a
single network interface, the mobile host/router would end up
with multiple Care-of Addresses (CoAs). In addition, the Home
Agent might be attached to multiple network interfaces, or to a
single network interface with multiple prefixes, hence resulting
in the option to use multiple IP addresses for the Home
Agent. This could result in the possibility of using a multitude
of bi-directional tunnels between pairs of {Home Agent address,
CoA} and a number of associated issues: establishment, selection
and modification of multiple simultaneous tunnels.

The objective of the WG is to produce a clear problem statement
and to produce standard track specifications to the problems
associated with the simultaneous use of multiple addresses for
either mobile hosts using Mobile IPv6 or mobile routers using
NEMO Basic Support and their variants (FMIPv6, HMIPv6,
etc). Where the effects of having multiple prefixes on a single
interface is identical to the effects of having multiple
interfaces each with a single prefix, the WG will consider a
generalized approach to cater for multiple prefixes available to
a mobile host/router.

The WG uses existing tunneling mechanisms defined for Mobile
IPv6. The involved nodes need to select which tunnel instance
to use when multiple ones are available due to multiple
addresses on either end. But the WG does not plan to define a
new mechanism for this, but rather document how to use existing
mechanisms based upon preferences or policies. In particular,
the WG will consider that a tunnel is alive as long as packets
can be exchanged with the corresponding peer. In addition, local
information, such as interface up/down events, or other failure
detection mechanisms can be used to quickly detect failure of

Deliverables related to this include

- A document explaining the motivations for a node using multiple
interfaces and the scenarios where it may end up with multiple
global addresses on its interfaces [Informational]

- An analysis document explaining what are the limitations for
mobile hosts using multiple simultaneous Care-of Addresses and Home
Agent addresses using Mobile IPv6, whether issues are specific to
Mobile IPv6 or not [Informational].

- A protocol extension to support the registration of multiple
Care-of Addresses at a given Home Agent address [Standard

- A "Flow/binding policies exchange" solution for an exchange of
policies from the mobile host/router to the Home Agent and from the
Home Agent to the mobile host/router influencing the choice of the
Care-of Address and Home Agent address. The solution involves two
specifications, one for the policy format and another for its
transport [both Standard Track].

(A.4) Work on solutions to deal with firewalls and the problems that
firewalls cause as identified in RFC 4487.

(A.5) Route optimization of network mobility.

Three use cases have been identified for this. These are called
the Aviation case, the Automotive case, and the Personal Mobile
Router (consumer electronics) case, though the actual technical
problems are characterized by the type of movements and
environments more than by the specific industry using the
technology. The group will explore these cases to gather
requirements and proceed with solving the open issues.

(1) Airline and spacecraft community, who are deploying NEMO for
control systems, as well as Internet connectivity and
entertainment systems. This use case is characterized by fast (~
1000 km/h) moving objects over large distances (across
continents). The main technical problem is that tunneling-based
solutions imply a roundtrip to another continent and that BGP
based solutions imply significant churn in the global Internet
routing table.

(2) Automotive industry who are deploying NEMO for in-car
communication, entertainment, and data gathering, possible
control systems use, and communication to roadside devices. This
use case is characterized by moderately fast (~ 100-300 km/h)
moving objects that employ local or cellular networks for

(3) Personal Mobile Routers, which are consumer devices that
allow the user to bring a NEMO network with the user while
mobile, and communicate with peer NEMO Basic Support nodes
and nodes served by them.

After gathering the requirements for these types of deployments,
the working group will evaluate what type of route optimization
needs to be performed (if any), and formulate a solution to
those problems.

If no requirements for those scenarios can be collected by the
deadline, it will be assumed that the work is premature, and
that type of deployment will be dropped from the WG.

The group will only consider airline and spacecraft solutions
that combine tunneling solutions for small movements with either
federated tunnel servers or slowly changing end host prefixes.
The group will only consider personal mobile router requirements
about optimized routes to another mobile router belonging to the
same operator. The group will only consider automotive industry
requirements to allow MR-attached hosts to directly access the
network where MR has attached to. Work on automotive and
personal mobile router solutions requires rechartering.

The WG will not consider extensions to routing protocols. The
group will not consider general multi-homing problems that are
not related to the deployment and maintenance of Mobile IPv6 or
NEMO Basic Support protocols. The group will also not consider
general route optimization, or other problems that are not
related to the deployment and maintenance of NEMO Basic Support
protocols. Similarly, the group will not consider or rely on the
results of general routing architecture, Internet architecture,
or identifier-locator split issues that are discussed in
separate, long term efforts elsewhere in the IETF. Finally, the
group will not consider solutions that require changes from
correspondent nodes in the general Internet

(A.6) Bootstrapping mechanisms developed earlier in the MIP6 WG
require AAA support for Mobile IPv6. Part of this work is
already being done in the DIME WG, but the MEXT WG is chartered
to complete a design for RADIUS.

Work items related to base specification maintenance include:

(B.1) Create and maintain issue lists that are generated on the basis
of implementation and interoperability experience. Address
specific issues with specific updates or revisions of the base
specification. One specific area of concern that should be
analyzed and addressed relates to multilink subnets.

This work item relates only to corrections and
clarifications. The working group shall not revisit design
decisions or change the protocol.

(B.2) Update the IANA considerations of RFC 3775 to allow extensions for
experimental purposes as well passing of optional vendor-specific

(B.3) Finish working group documents that are currently in process, and
submit for RFC. This includes prefix delegation protocol mechanism
for network mobility, and a MIB for NEMO Basic Support.

Work items related to informational documentation include:

(C.1) Produce a design rationale that documents the historical
thinking behind the introduction of an alternative security
mechanism, the Authentication Protocol (RFC 4285).

The group employs IPsec and IKE as a security mechanism. The group
shall refrain, however, from making generic extensions to these
protocols. Any proposed extension must be reviewed by the ADs
before it can be accepted as a part of a work item.

Goals and Milestones:

Done  Submit I-D 'Mobile IPv6 Vendor Specific Option' to IESG for publication as a Proposed Standard
Dec 2007  Submit I-D 'Mobile IPv6 Dual-Stack Operation' to IESG for publication as a Proposed Standard.
Dec 2007  Submit I-D 'Motivation for Authentication I-D' to IESG for publication as Informational.
Dec 2007  Submit Multiple CoA Registration to IESG
Done  Submit I-D 'Mobile IPv6 Experimental Allocations' to IESG for publication as a Proposed Standard
Feb 2008  Submit I-D 'Goals for AAA HA Interface' to IESG for publication as Informational.
Feb 2008  Submit -00 draft on Route Optimization needs for Personal Mobile Router
Feb 2008  Submit -00 draft on Route Optimization Needs for Automobile and Highway Deployments
Feb 2008  Submit -00 draft on Route Optimization Needs for Aircraft and Spacecraft Deployments
Mar 2008  Submit the final doc on Prefix Delegation for NEMO to the IESG, for Proposed Standard
Done  Submit I-D 'Mobility Header Home Agent Switch Message' to IESG for publication as a Proposed Standard
May 2008  Submit final doc on Route Optimization needs for Personal Mobile Router, for Informational
May 2008  Submit final doc on Route Optimization Needs for Automobile and Highway Deployments, for Informational
May 2008  Submit final doc on Route Optimization Needs for Aircraft and Spacecraft Deployments, for Informational
May 2008  Submit -00 draft for solution to aircraft/spacecraft problem
Jun 2008  Determine how to proceed with remaining automotive/Personal Mobile Router solutions
Jun 2008  Submit the I-D 'RADIUS Mobile IPv6 Support' to IESG for publication as a proposed standard.
Jul 2008  Submit Analysis of the use of Multiple Simultaneous Care-of Addresses and Home Agent addresses, for Informational
Jul 2008  Submit Multiple Interfaces Motivations and Scenario to IESG, for Informational
Aug 2008  Submit I-D 'Mobile IPv6 Operation with Firewalls' to IESG for publication as Informational.
Aug 2008  Submit the final doc on MIB for NEMO Basic Support to the IESG, for Proposed Standard
Oct 2008  Submit Flow/binding policy transport to IESG, for Proposed Standard
Oct 2008  Submit Flow/binding policy format to IESG, for Proposed Standard
Nov 2008  Submit final doc for solution to aircraft/spacecraft problem to the IESG, for Proposed Standard
Nov 2008  Recharter to work on the remaining automotive/Personal Mobile Router solutions
Dec 2008  Submit I-D(s) related to specific updates and corrections of RFC 3775 to IESG for publication as Proposed Standard.
Dec 2008  Submit I-D 'Home agent reliability' to IESG for publication as a Proposed Standard.


  • draft-ietf-mip6-nemo-v4traversal-06.txt
  • draft-ietf-monami6-mipv6-analysis-04.txt
  • draft-ietf-monami6-multiplecoa-06.txt
  • draft-ietf-mip6-hareliability-03.txt
  • draft-ietf-mip6-radius-04.txt
  • draft-ietf-mip6-generic-notification-message-00.txt
  • draft-ietf-mext-aero-reqs-01.txt
  • draft-ietf-mext-aaa-ha-goals-00.txt
  • draft-ietf-mext-nemo-v4traversal-01.txt
  • draft-ietf-mext-nemo-mib-00.txt
  • draft-ietf-mext-nemo-ro-automotive-req-00.txt

    No Request For Comments

    Meeting Minutes


    None received.