Subject: [multimob] MULTIMOB BOF outcome

From: Jari Arkko <[email-masked]>
Date: Thu, 13 Aug 2009 15:27:56 +0300

I have been thinking about what to do about this. My (remote)
interpretation of the meeting was that people in the room felt a WG is
needed and that the charter was reasonable. Due to scheduling and other
reasons I don't think this is the entire picture, however. I think parts
of the mobility community still feel that a working group is an overkill
and/or the optimization work is unwarranted. However, I am personally
quite convinced that _some_ work is needed, given, for instance, the
fact that while implementing some forms of multicast in proxy MIP is
easy, the word multicast doesn't appear in the specification.

I think we have realistically three options:

1. Put the work in an existing WG, such as NETEXT, as a part of
extensions and clarification work on proxy MIP.
2. Create a new working group, but tune the charter from the proposed
one into a little bit more restrictive, mainly to remove too much
optimization work. Once this work is complete, we can more confidently
let the working group do the optimization work as well.
3. Creata a working group as requested.

I'm leaning on alternative 2, thoughts? Here's a proposed charter:

Mobility Multicast (multimob)

Chairs:
TBD

Internet Area (int) Directors:
Jari Arkko <[email-masked]>
Ralph Droms <[email-masked]>

Internet Area Advisor:
Jari Arkko <[email-masked]>

Mailing Lists:
General Discussion: [email-masked]
Subscribe online at: https://www1.ietf.org/mailman/listinfo/multimob

Description of Working Group

The Multicast mobility (multimob) working group provides guidance for
supporting multicast in a mobile environment. The scope of work will
be limited to Proxy Mobile IPv6, MLD/IGMP protocols and listener
mobility. Work requiring modifications to mobility protocols,
MLD/IGMP, and multicast routing protocols is out of scope in this
first stage of this working group.

Specific goals are:
- Document how multicast can be supported in a Proxy Mobile IPv6
environment
- Document the configuration of IGMP/MLD in mobile environments

The Proxy Mobile IPv6 (PMIPv6) specification as defined in RFC 5213
does not describe how to support multicast. Some forms of multicast
support can, however, be built in the involved nodes by using existing
capabilities of multicast protocols and the underlying mobility
protocols. The first task of the working group is to document such
solutions for PMIPv6. This work will not require any additions or
changes to message types and parameters specified in RFC 5213, and
will assume an unmodified mobile host. The work will employ the remote
subscription model. This is mechanism by which a mobile node joins a
multicast group and receives multicast data forwarded via the local
mobility anchor.

IGMPv3/MLDv2 has been specified for wired networks with shared links.
Mobile nodes have needs that are specific to wireless networks and
mobility (e.g. entering a dormant mode to conserve battery power,
minimizing the latency for joining and leaving a group in support of
movement).

The second task of the WG is to assess existing solutions for group
management, and determine to what extent these methods are sufficient
in a mobile environment. This will include recommending appropriate
selection of timer values and protocol parameters.

In performing its work, the working group will work closely with both
the mobility community (NETLMM and NETEXT WGs) and the multicast
community (MBONED WG). The group will consider both source specific
multicast and any source multicast multicast models.

Future work, subject to rechartering, may study/evaluate extensions to
support PMIPv6 optimizations to address the avalanche problem and fast
handover and extensions to IGMPv3/MLDv2 to support better operation in
mobile environments.

Milestones:

Nov 2009  Initial version of a document explaining the use of multicast
in PMIPv6
Nov 2009  Initial version of a document on how to tune IGMP/MLD for
mobility
Feb 2010  Submit a document explaining the use of multicast in PMIPv6,
for publication as either Informational or Best Current Practice
Feb 2010  Submit a document on how to tune IGMP/MLD for mobility, for
publication as either Informational or Best Current Practice
Mar 2010  Recharter for additional optimization work involving
extensions to PMIPv6, IGMPv3, or MLDv2

---

From: "Thomas C. Schmidt" <[email-masked]>
Date: Thu, 13 Aug 2009 14:57:44 +0200

Dear Jari,

many thanks for your thoughtful considerations.

Your proposed modifications to the charter put a very nearby and narrow 
focus, which I believe is doable on the basis of the preliminary work 
that is already around.

... and yes, I can share your sensing of need for broader consensus on 
'Multimob work' - given previous debates, it should be convincing to see 
a first outcome that is of practical value and nicely integrates into 
existing protocols of mobility and of multicast.

So, personally I could go along well with your proposal.

Btw. - there is a typo in the charter text:

PMIPv6 paragraph, last sentence should be
"This is *a* mechanism by which a mobile node joins a multicast group 
and receives multicast data forwarded via the local mobility anchor."

Thanks,

Thomas

Jari Arkko wrote:
> _______________________________________________
> multimob mailing list
> [email-masked]
> https://www.ietf.org/mailman/listinfo/multimob

-- 

Prof. Dr. Thomas C. Schmidt
° Hamburg University of Applied Sciences                   Berliner Tor 7 °
° Dept. Informatik, Internet Technologies Group    20099 Hamburg, Germany °
° http://www.haw-hamburg.de/inet                   Fon: +49-40-42875-8452 °
° http://www.informatik.haw-hamburg.de/~schmidt    Fax: +49-40-42875-8409 °

---

From: Frank Xia <[email-masked]>
Date: Thu, 13 Aug 2009 09:26:04 -0500

Hi Jari

I agree with you.

Alternative 2 is quite fair.

BR
Frank

---

From: Hitoshi Asaeda <[email-masked]>
Date: Fri, 14 Aug 2009 00:54:18 +0900 (JST)

Hi Jari,

> first stage of this working group.

IMO, it is too early to decide to eliminate the discussions of
protocol modifications.
And what is the expected efforts or advantages by completely
eliminating the discussions of protocol modifications in this group?
Without discussions of protocol modifications, what kinds of
deployment scenarios do you expect?

I cannot get the great benefit of eliminating such discussions, by
explicitly mentioning "modifications to mobility protocols, MLD/IGMP,
and multicast routing protocols is out of scope".

In my sense, some of protocol modifications are not always for
"optimization", but for "necessary discussion for its deployment".

I'd therefore say keeping discussion space for protocol modifications
is better, even with the lower priority than Info/BCP documents.

Any thoughts?

Regards,
--
Hitoshi Asaeda

---

From: Behcet Sarikaya <[email-masked]>
Date: Thu, 13 Aug 2009 13:45:55 -0700 (PDT)

Hi Hitoshi,
  Nobody is saying protocol modifications will not be considered. The charter text is very clear as you cited below "in this first stage of this working group" where no protocol modifications apply.

  Considering protocol modifications a little bit later for example in 2010 in the context of rechartering is OK, IMO.

Regards,

Behcet

----- Original Message ----
> From: Hitoshi Asaeda <[email-masked]>
> To: [email-masked]
> Cc: [email-masked]
> Sent: Thursday, August 13, 2009 10:54:18 AM
> Subject: Re: [multimob] MULTIMOB BOF outcome
> 
> Hi Jari,
>

---

From: Matthias Waehlisch <[email-masked]>
Date: Fri, 14 Aug 2009 00:47:12 +0200

Hi Hitoshi, hi all,

On Fri, 14 Aug 2009, Hitoshi Asaeda wrote:

> IMO, it is too early to decide to eliminate the discussions of protocol 
> modifications.
[...]
  that's no problem if you look on the very short-term charter. A 
re-chartering is scheduled for the 77th IETF ... A narrow scope with a 
tight schedule is fine. I vote for option two, as well - it's a good 
chance to start with the topic at all.

Regards
  matthias

-- 
Matthias Waehlisch
.  FU Berlin, Inst. fuer Informatik, AG CST
.  Takustr. 9, D-14195 Berlin, Germany
.. mailto:[email-masked] .. http://www.inf.fu-berlin.de/~waehl
:. Also: http://inet.cpt.haw-hamburg.de .. http://www.link-lab.net

---

From: Stig Venaas <[email-masked]>
Date: Thu, 13 Aug 2009 16:40:33 -0700

> chance to start with the topic at all.

I agree. It makes sense to focus on getting those fundamental documents
done first. Making the initial charter very focused is probably good,
and the initial documents would be of use to any further work in the
area.

Stig

---

From: Liu Hui <[email-masked]>
Date: Fri, 14 Aug 2009 09:58:00 +0800

Hi all,

I agree with stig that the fundemental documents are necessary to be
prepared as the guidance for the future work.

And option 2  proposed by Jari seems a reasonable compromise at this moment.

BRs,
Liu Hui

> -----Original Message-----
> From: [email-masked] 
> [mailto:[email-masked]] On Behalf Of Stig Venaas
> Sent: Friday, August 14, 2009 7:41 AM
> To: Matthias Waehlisch
> Cc: [email-masked]
> >>> The Multicast mobility (multimob) working group provides guidance 
> >>> for supporting multicast in a mobile environment. The 
> scope of work 
> >>> will be limited to Proxy Mobile IPv6, MLD/IGMP protocols and 
> >>> listener mobility. Work requiring modifications to mobility 
> >>> protocols, MLD/IGMP, and multicast routing protocols is 
> out of scope 
> >>> in this first stage of this working group.
> I agree. It makes sense to focus on getting those fundamental 
> documents done first. Making the initial charter very focused 
> is probably good, and the initial documents would be of use 
> to any further work in the area.
> 
> Stig
> 
> > Regards
> >   matthias
> > 
>

---

From: <[email-masked]>
Date: Fri, 14 Aug 2009 10:08:47 +0200

Hi all,
 
As we already had envisaged to focus on the BCP document w/o protocol modifications in the first phase anyway, IMHO the actual difference is not too large between options 2 and 3. Of course it would be nice to have the 'complete program' for the WG in the very beginning, but as chances to start with work at all seem to increase with the two-stage approach, I am fine with Jari's proposal and a very concise roadmap.
Once we have shown in detail the remaining open issues for deployment the justification for work extension is even better so that re-chartering should face no real trouble ;-) ...

Thanks!

Best regards,
Dirk

-----Ursprüngliche Nachricht-----
Von: [email-masked] [mailto:[email-masked]] Im Auftrag von Matthias Waehlisch
Gesendet: Freitag, 14. August 2009 00:47
An: Hitoshi Asaeda
Cc: [email-masked]
Betreff: Re: [multimob] MULTIMOB BOF outcome

Hi Hitoshi, hi all,

[...]

Regards
  matthias

---

From: Xiaoming Fu <[email-masked]>
Date: Fri, 14 Aug 2009 22:59:26 +0200

+1

Xiaoming

---

From: jouni korhonen <[email-masked]>
Date: Mon, 17 Aug 2009 11:56:13 +0300

Hi,

If we go for alternative 2 (which would be ok), the proposed modified  
charter is now more or less what I wanted & proposed earlier. I would  

> subscription model. This is mechanism by which a mobile node joins a

s/will assume/must assume

> extensions to PMIPv6, IGMPv3, or MLDv2

Do we need to say here also "..or close the WG" ?

Cheers,
	Jouni

---

From: Jari Arkko <[email-masked]>
Date: Mon, 17 Aug 2009 12:09:40 +0300

Jouni,

I like the suggested wording changes.

Jari

---

From: Gorry Fairhurst <[email-masked]>
Date: Mon, 17 Aug 2009 13:53:54 +0100

OK with me too.

However, I think the decision to progress the IGMP/MLD protocol changes 
could be made independently of the decision for PMIP extension: these 
changes seem less architectural and have been discussed a number of 
times in the past - however, I think it would also be essential to first 
identify the solution space and produce the BCP/INFO on this topic, 
before advancing any PS.

Gorry

---

From: Jari Arkko <[email-masked]>
Date: Mon, 17 Aug 2009 16:26:23 +0300

Gorry Fairhurst wrote:
>
> OK with me too.
>
> However, I think the decision to progress the IGMP/MLD protocol 
> changes could be made independently of the decision for PMIP extension: 

Perhaps we need two separate milestones for the two different tracks and 
their associated rechartering events.

Jari

---

From: Gorry Fairhurst <[email-masked]>
Date: Mon, 17 Aug 2009 15:43:45 +0100

> their associated rechartering events.
That could work, or have one rechartering discussion, but remember there 
are two separate issues to be addressed and both need decisions.

Gorry

---

From: Behcet Sarikaya <[email-masked]>
Date: Mon, 17 Aug 2009 08:36:08 -0700 (PDT)

----- Original Message ----
> From: Gorry Fairhurst <[email-masked]>
> To: Jari Arkko <[email-masked]>
> Cc: [email-masked]
> Sent: Monday, August 17, 2009 9:43:45 AM
> >> However, I think the decision to progress the IGMP/MLD protocol changes could 
> be made independently of the decision for PMIP extension: 
> > 
> > Perhaps we need two separate milestones for the two different tracks and their 
> associated rechartering events.
> > 
> > Jari
> > 
> > 
> That could work, or have one rechartering discussion, but remember there are two 
> separate issues to be addressed and both need decisions.
> 

I don't really see this as an issue that requires any charter text changes.
Let's keep the charter text as is and during rechartering, make sure not to mix up the protocol changes in two very different protocols.

Regards,

Behcet