Network-Based Mobility Extensions

Document Charter Network-Based Mobility Extensions WG (netext)
Title Network-Based Mobility Extensions
Last updated 2009-05-19
State Approved
WG State Concluded
IESG Responsible AD Suresh Krishnan
Charter Edit AD (None)
Send notices to (None)


Proxy Mobile IPv6, specified in RFC 5213, is a network-based mobility
  protocol. It uses a Mobile Access Gateway (MAG) and a Local Mobility
  Anchor (LMA) to allow hosts to move around within a domain while keeping
  their address or address prefix stable. Proxy Mobile IPv6 has been
  incorporated into a number of products and deployments are starting.
  Certain deployment considerations, including localized routing and bulk
  refresh of lifetime are already emerging.
  The working group will focus on the following topics relevant for
  network-based mobility:
  Localized Routing: a specification for routing traffic between the
  MAG(s) without involving the LMA. That is, allow the MAGs to route
  traffic between hosts from one MAG to another, without being tunneled
  all the way to the LMA. This reduces latency and backhaul load.
  Applications such as voice can benefit from the reduced latency.
  The working group will produce a problem statement and a
  specification of the localized routing mechanism.
  Bulk Refresh: a specification of improving the signaling load for
  binding lifetime refresh. The current specifications call for the
  handling of each mobility session independent of each other. When a
  large number of hosts are served by a single MAG, a periodic refresh of
  the binding lifetimes can lead to a signaling storm. The purpose of the
  Bulk Refresh feature is to construct a protocol feature that allows such
  refreshes to occur on a per-MAG basis.
  LMA Redirection: a specification for allowing an LMA to redirect a MAG
  to another LMA. This is primarily needed as a way to perform load
  balancing. This functionality is complementary to implementation
  techniques that allow distributed MAG implementations to move tasks
  around without a visible impact at the protocol level, and the
  initial LMA discovery work in the NETLMM WG. An applicability statement
  describing the situations where the new functionality is or is not
  applicable has to be included in the specification.
  Hiding access technology changes from host IP layer: Proxy mobility is
  based on the assumption that changes in host IP stacks are
  undesirable. However, link layer implementations can hide the
  actually used physical interfaces from the IP stack. For instance, a
  "logical interface" at the IP layer may enable packet
transmission and   reception over different physical media. Such
techniques can be used   to achieve inter-access handovers or flow
mobility, i.e., the movement   of selected flows from one access
technology to another. It is   assumed that an IP layer interface can
simultaneously and/or   sequentially attach to multiple MAGs (possibly
over multiple media).   The hiding mechanisms also need to work together
with existing RFC   5213 handover hint mechanisms. The specification of
any actual link   layer mechanisms is outside the scope of the working
group, but the   group works on the following:     -
Informational applicability statement that analyzes the issues   involved
with this approach and characterizes the contexts in which   such use is
or is not appropriate.     - The working group will determine what
protocol extensions are   required between the Proxy Mobile IPv6 network
nodes (MAGs and LMAs)   to support the ability for an interface (at the IP
layer) to   transmit packets over different media, the ability to
distribute   specific traffic flows on different media components of that
  interface, and making this work with the handover hints in the base
  protocol. The relevant protocol extensions will be developed as  
necessary.     Radius Extensions to PMIP6: In order to enable network
based   mobility using PMIP6, the policy profile needs to signal a set of
  attributes and policies to the MAG and LMA. New Radius attributes  
need to be specified that are relevant to PMIP6 based   mobility. This
work item will specify Radius extensions and   attributes specific to
PMIP6.     The work in this charter is entirely internal to the
network and does   not affect host IP stack operation in any way (except
perhaps through   impacting packet forwarding capacity visible to the
hosts). The working   group is not allowed to specify new IP layer
protocol mechanisms to   signal mobility related events between the host
and the network.     The proposed activity will be complementary to
the existing IETF Working   Groups, notably the NETLMM and MEXT WGs. The
NETEXT working group will   also act as the primary forum where new
extensions on top of the Proxy   Mobile IPv6 protocol can be developed.
The addition of such new   extensions to the working group involves
addition of the extension to   this charter through the normal
rechartering process.