Rev 2; Jan 16, 09

Network-based Mobility Extensions (NetExt) BOF proposal:
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Background and Motivation:
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Proxy MIP6, which is the IETF Network-based Mobility Protocol
specified in RFC 5213, has been incorporated into the evolved
architecture of Long-Term Evolution (LTE) and Wimax networks. The
respective standards organizations are in the process of specifying
the Proxy MIP6 protocol for their current requirements and outlining the
enhancements for subsequent releases of these networks. In light of
the above, the following observations can be made: 

o as the trials and deployments of 4G networks are expected to begin
  in 2009, their evolution to support features such multihoming,
  inter-access technology handovers and localized routing
  continues

o while the base PMIPv6 protocol is completed, improvements are
  necessary in some areas, most notably multihoming and 
  inter-access technology handovers 

o certain deployment considerations, including localized routing and
  bulk refresh of lifetime are already emerging

In summary, improvements, deficiencies and deployment considerations
are identified to extend the network-based mobility (i.e., PMIPv6) to
better meet the evolution of 4G mobile networks. 

Prior activity:
--------------

The NetExt Bar BoF was held during the Dublin IETF meeting on
Thursday, July 31 from 1300 - 1500. Subsequently another followup
meeting of interested contributors was held at IETF73 in
Minneapolis. The primary purpose of the BOF was 
to investigate problems of relevance to the Network-based mobility
protocol (i.e., PMIPv6) and its adoption in the industry. Three main
categories of problems - Improvements, Deployment Considerations and
Deficiencies were discussed. There were a total of 12 presentations,
and a summary presentation/discussion was held in the final half hour.  
There was consensus that the current charter and roadmap of the NETLMM
Working Group makes it imperative to pursue the above-mentioned
categories of problems in a separate, complementary WG. 
There was overwhelming support among the approximately 40 people who
attended the Bar BoF in working on the proposed items. Over 25 people
who are interested in contributing to the work attended the Netext
special-interest-group meeting in Minneapolis. Work on defining the
problem statements for the proposed work items is now in
progress. There were no objections to creating a potential WG in the
Internet Area.  

Proposed Work:
-------------

The proposed NetExt Working Group will focus on the following topics
relevant for network-based mobility:

 Improvements:

   o Multihoming: a specification including the target scenarios,
   preservation of IP sessions and load balancing (Proposed Standard)
  
   o Inter-access Technology handovers: a specification for IP session
   preservation when changing access technologies (PS)

 Deployment Considerations:

   o Localized Routing: a specification for constraining routing to
   the MAG(s) without involving the LMA within a single PMIPv6
   domain (PS)

   o Bulk Refresh: specification of improving the signaling load for
   binding lifetime refresh (PS)

 Deficiencies:

   o MN involvement: documentation of scenarios where MN involvement
   may be seen as beneficial (Informational)

The BoF proposes to discuss the above items and gauge interest in
forming a working Group. There is already work in progress addressing
the identified problems, which is expected to be the starting point
for the deliverables. 

The proposed activity will be complementary to the existing IETF
Working Groups, notably the NETLMM and MEXT WGs. 

Approximate Timeline for Deliverables:
-------------------------------------

March 2009  WG approved by IESG 
2Q09  	       Problem statements for multihoming, localized routing
	       and inter-access HO agreed upon in the WG
2H09           Submit Inter-access Tech Handover, Localized Routing
               and Multihoming I-Ds to IESG  
4Q09           Submit the I-D on MN Involvement to IESG 
1Q10           Submit Bulk Refresh I-D to IESG 
2H10           Recharter or close WG