Subject: [seamoby] Seamoby WG meeting minutes for San Diego IETF

From: Pat Calhoun <[email-masked]>
Date: Fri, 12 Jan 2001 15:38:27 -0800 (PST)

Please find the attached minutes for the meeting.

Thanks,

PatC
49th IETF in San Diego
Seamoby Working Group

Chairs: Pat Calhoun ([email-masked])
	Phil Neumiller ([email-masked])

minutes by: La Monte Henry Piggy Yarroll ([email-masked])

Meeting Summary:

As a result of the meeting, three design groups were formed. James Kempf
([email-masked]) will lead the paging team, Dana Blair
([email-masked]) will lead the micro-mobility team, while Gary Kenward
([email-masked]) will lead the context transfer team).

The design teams are responsible for coming up with a problem statement
for their respective area.

Minutes:

1. Agenda

  Agenda Bashing
  Ground Rules
	- Chairs are very firm about charter.
	- White gloves only
  Milestones
	- Layer 3 paging
	  A point was made that the working group should first handle context
	  transfer, given that this was the most complicated work item.
	  The chair stated that all work will progress in parallel.

	  Another point was made that paging should exist in the Mobile IP WG,
	  but MIP has already agreed that paging is not within its charter.

	- Micro-Mobility
	  A point was made that a succinct definition of WHAT Micro-mobility
	  IS, is lacking from OUR COMMON VOCABULARY.

	  Sampling question:  Do we need to reassess?  Is MobileIP becoming
	  sufficient (see 3 above)?
	  We need a clear problem statement.

	  A point was made that MIP may be sufficient, but there are scenarios
	  that might need more than MIP. We need some scenarios. Is MM mobility
	  within a subnet? Why doesn't MIP solve this? Why aren't the current
	  radio protocols sufficient?

	  The MIP WG co-chair stated that we should explore the possible
	  solutions which MIP is NOT exploring. There is an ID presented
	  that has such a problem description., which will be presented
	  in the meeting.

	  The chair stated that we need a set of requirements.  We need a
	  separate design team for a problem statement and a set of
	  requirements.

	  Ideally, submit candidate protocols around about 22 February.
	  REQUIRED is a document that compares the protocol to the
	  requirements.

	  A comment was made that we should not over-narrow the scope of the
	  WG. Another comment was made that some Mobile IP submissions might
	  be relevant to some of our work items, and that we should take a
	  closer look at what's going on in MIP.

	  An evaluation team will then select a protocol from the submitted
	  candidates. A comment was made that evaluation teams are against
	  the IETF mantra, and the working group should be the one that
	  decides. There was some concern as to whether one single solution
	  could be chosen, which the AD responded that one is sufficient,
	  more would create confusion in the marketplace. There was many
	  discussions on whether one or more problems are appropriate, and
	  the problem description should address that issue.

	  There was another thread that questioned what kind of solutions are
	  appropriate, whether it's routing, link or application. Some 
	  suggested routing.

	- State Transfer

	  There are three options that the WG should evaluate:
	    1. Have the network nodes transfer state
	    2. Let the mobiles upload their state
	    3. Let the mobiles renegotiate with network
	  Comments were made that the first option seems most likely, and
	  would probably best provide seamless mobility.

	  There was some discussion on what state transfer is, and isn't,
	  but a problem statement is required, as per our charter, for
	  the IESG to decide whether the work will be done.

2. Seamoby Reference Model

  Phil Neumiller presented a reference model with a picture of some
  kinds of MIP peer within IP and "Hints" going down to layer 2. 
  There was also another diagram provided by Phil that shows a network 
  doing a vertical handoff. There was much controversy on what the pictures 
  meant, and where some functions resided, but the main focus was to show 
  that multi-technology handoffs should be possible. How it is done is
  something that can only be answered once a problem statement has been
  written.

  There were more discussions on how QoS is affected in a seamoby
  environment, and another diagram showing an actual handoff taking
  place. There was a comment that Mobile IP already solves this problem,
  but Mobile IP doesn't handle mobile routers or subnets.

3. Seamoby Concerns (John Loughney)

  John Loughney presented some concerns, and in his presentations he showed
  a long list of handover types, followed by a list of definitions of the
  various handover types, such as seamless, fast, smooth, etc. There was
  a slide that discussed context transfer, which may include compression state,
  policy, security, etc. There was a question as to what kind of state we
  really want to send, what makes sense? There was a comment that end-to-end
  QoS is obviously out of scope, given that the edge has no control over
  the network (and the endpoint), so there are no QoS guarantees.

  John then presented some of his requirements, which are:
	-- IPv6-friendly
	-- Split micro/macro  (e.g. minimize reauthentication)
	-- Layer 2 independent, but use what we can
	   "Do what you can locally, but go global when necessary."
	-- minimize air signaling
	-- applications should not need to be mobile-aware
	-- Security is important

  His drafts will be announced on the mailing list.

4. SeaMoby Header Compression (Rajeev Koodli)

  Rejeev is presenting his two Internet Drafts:
	draft-koodli-rohc-hc-relocate-00.txt
	draft-koodli-mobileip-smoothv6-00.txt

  The problem is how to move the compression state from an
  old router to a new router. The proposed solution is HCRP,
  where the MN asks the new router to fetch the context from
  the old router.

  There are many compression profile types, so what kind of
  compression info is needed? A possible work item is to define
  a bunch of compression profiles, but a question was raised as
  to what the savings were. The response was that packet loss over
  the air could cause problems for state handoff.

5. Cellular IP

  Andrew Campbell presented Cellular IP, and stated that more information
  on Cellular IP can be found on the web site (both the code and the docs).
  The discussion was not Mobile IP does not scale as well as IP, and that
  something new is required. Many comments were made in regards to this
  presentation, but the fact of the matter is that we need to understand
  the problem before we look into the solutions.

  More questioned how a stateful protocol can be more scalable than a
  stateless protocol, and questions on how L3 paging can be used, etc.
  However, these were all solutions, and not requirements.

  There was a comment on why this presentation was made here, given that
  we aren't at the solutions stage yes, which drew some applause some the
  audience. The response from the chair was fairness.

6. State transfer between Access Routers during Handoff

  Context Transfer++ (draft-oneill-handoff-state-00.txt) was
  presented, and briefly summarized some of the states that need
  to be transferred to expose some of the gory bits. The transferred
  state might have some attachment to surrounding universe of the
  edge router. 

  Some approaches were discussed, such as allowing the mobile to rebuild
  the state on the new router using the appropriate protocols (e.g. RSVP,
  Mobile IP, etc). It was noted that it make take several seconds to
  rebuild the state. Another approach is to assume that the Mobile Node
  can securely upload all of the state to the new router, but the
  speaker stated that there are some trust issues in this model. Another
  model is to allow the routers to exchange the states directly.

  An example of state that could be transferred was multicast information.
  We could not do anything, and let the mobile rejoin, have the mobile 
  send IGMP information to the router, or have the old router send the
  IGMP information to the new router.

  The recommended approach was to document the state, design a solution
  and document it per protocol. First, we should document the requirements
  for generalized context transfer.

  There were questions whether this could be handled at layer 2, and 
  the feeling was no.

  A question was raised why is there a need for seamless handoff in the
  first place, where Charlie Perkins answered "S a m e s H nd  v r".

7. Buffer Mgmt (Charlie Perkins, the Tallest MIP Designer)

  Rate of beacons in MIP is too slow to do voice buffering, but if you
  increase the beacon rate you can make it work.
  Hand over 2-3 buffers and you get pretty-good results.
  Holy Grail:  Do smooth voice hand-over.
  Problem statement (paraphrase): "Mobile node has some context and
  needs to retrieve it later..."

8. Realtime Mobile IPv6

  Dana Blair presented draft-blair-rt-mobileipv6-seamoby-00.txt. The
  goals of the draft are:
	- Address HO for realtime within subnets (micro) and
	  between subnets (macro).
	- Address access, AAA, QoS, IPSec, handoff signaling.
	- Common terminology
  Dana presented some Micro-Mobility objectives, which should become
  requirements:
	- Minimize packets sent/received by mobile
	- Minimize time between access link changes
	- Minimize lots of other stuff...
	  Ditto for Macro-mobility

  There were a few proposed solutions:
	- Combine the whole mess into a single message from the mobile
	- Cache context
	- Re-use existing protocols
	- Avoid a new protocol

  There was a question whether minimizing packets meant round trips,
  and the speaker answered that packets matter too. Another questioned
  why multicasting was missing (as a state to transfer), and the answer
  was that it hadn't come up, and it did complicate the problem. Another
  questioned whether a single packet solution (to transfer state)
  generalized lots of other stuff, but someone stated that some state
  information may not fit in a single packet. Lastly, someone questioned
  the reliability of a single packet handoff.

9. Next steps
  Chair: Who wants to participate in the problem statement?  (Many hands)
  Who wants to do the administrative overhead?
  Context Transfer: Gary Kenward
  MM: Dana Blair
  Paging: James Kempf

  A comment was made that all micro-mobility people should simply post
  their comments to the main list. A follow-on stated that everybody has
  their own terminology, and a team would help tp to unify the terminology.

  Another comment was made that the dates in the milestone are too aggressive.
  The chair responded that this was caused by the latency in fixing the
  charter to address IESG comments, and its approval. This can be changed at
  the next charter review.