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Mobile Nodes and Multiple Interfaces in IPv6

Document Charter Mobile Nodes and Multiple Interfaces in IPv6 WG (monami6)
Title Mobile Nodes and Multiple Interfaces in IPv6
Last updated 2007-11-20
State Approved
WG State Concluded
IESG Responsible AD Jari Arkko
Charter edit AD (None)
Send notices to (None)


There is currently rapid development in the area of new wireless
standards (802.11*, 802.16, 802.20, UMTS, Bluetooth and others). At
the same time, terminals which have radio and protocol support for
two, three or even more standards are appearing. This opens the
possibility of using multiple access types simultaneously, with each
access used to transport the traffic for which it is most
appropriate. For instance, an intermittent, but high-bandwidth access
type might be used for file transfers (e.g. music download) while a
low-bandwidth, high reliability access might simultaneously be used
for a voice call.

In the meantime, IP-level mobility support protocols such as Mobile
IPv6 (RFC 3775) and NEMO Basic Support (RFC 3963) have been conceived
by the IETF to support handoffs for IPv6 mobile hosts and routers,

However, these protocols do not today provide standardized support for
simultaneous differentiated use of multiple access technologies,
although 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. Some of the issues are very specific to mobility and are
generally applicable to both mobile hosts and mobile routers using
Mobile IPv6 and NEMO Basic Support respectively. Some of these issues
can be resolved with relatively small and straight-forward changes to
Mobile IPv6 and NEMO Basic Support (e.g. multiple CoAs registration).

The objective of the Monami6 WG is to produce a clear problem
statement and to produce standard track specifications to the
straight-forward 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, Monami6 will consider a generalized
approach to cater for multiple prefixes available to a mobile
host/router. Once this is done, the WG might re-charter in order to
work on more generic issues that prevent taking advantage of the
multiple CoAs and HoAs available to mobile nodes and routers.

The WG does not plan to define a tunnel selection mechanism, but may
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 tunnel(s).

WG Deliverables:

  • 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 Mobile IPv6 (RFC 3775) and NEMO Basic
    Support (RFC 3963) to support the registration of multiple Care-of
    Addresses at a given Home Agent address [Standard Track].

  • 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 [Standard Track].