Subject: [multimob] Minutes

From: Behcet Sarikaya <[email-masked]>
Date: Mon, 16 Nov 2009 14:05:49 -0800 (PST)

Hi all,
  Minutes of last week's meeting have been posted at:
http://www.ietf.org/proceedings/09nov/minutes/multimob.txt

Many thanks to Dirk von Hugo and Matthias Waehlisch for taking the minutes so precisely.

Also thanks to Marshall Eubanks for scribing the Jabber notes at
http://www.ietf.org/jabber/logs/multimob/2009-11-12.txt

Please check the minutes and let us know if any changes are needed.

Regards,

Behcet

---

From: Stig Venaas <[email-masked]>
Date: Mon, 16 Nov 2009 14:32:17 -0800

> Please check the minutes and let us know if any changes are needed.

I think the minutes are a bit too condensed. I think some points may
have been missed.

Behcet, I propose using the minutes attached to this email. They are
in a more verbatim style. Or at least some points in the minutes you
posted should be extended.

Stig

> Regards,
> 
> Behcet
> 
> 
>       
> _______________________________________________
> multimob mailing list
> [email-masked]
> https://www.ietf.org/mailman/listinfo/multimob

Multicast Mobility WG
======================================
 
Thursday, November 12 2009, 
1300-1500, Room : Cattleya West

Behcet: Presented the agenda and the IETF Note-Well.
Stig: Clarified the charter. First, we have to work on basic stuff, but
keep working on optimization extensions in the background.
Jari: Some motivation for the basic stuff: Do it fast and well, then you can
work on optimizations.
Stig: What do we mean with basics: Multicast support without changes to PMIP
and other protocols.

IGMP/MLD for Mobility
 
Hitoshi presents his ideas how optimization can take place w/o protocol
modification. 

Stig: Draft interesting, it covers different ways to solve some problems,
which are part of the charter. However, charter is fairly strict. Split the
draft. Regarding the timers, it is hard to find values that cover all
scenarios.
Hitoshi: Agree, it is really hard to find specific timer values. Maybe, we
can introduce some correlations and describe situations. But it is really
hard to define dedicated timer settings. We should clarify this discussion.
Thomas Schmidt: The number of retransmits is also important in wireless
scenarios. I agree with Stig and Hitoshi: We should define characteristic
values with respect to technologies.
Suresh Krishnan: I agree. It would also be useful to explain how the modified
values affect the protocol operations.
Thomas: Slowing down the timers preserve WLAN resources but may affect
protocol behaviour (cf. discussions on the mailing list). One has to discuss
this part, as well.
Hitoshi: I don't want to introduce very, very short intervals to cover
mobility, it's harm. 
Thomas: You cannot assume that MNs use this in the future.

Light Weight IGMP/MLD.
Jari thinks that profiling (e.g. as would be a pointing to LW protocols)
is ok, guidelines should be given ... if this is not possible then state so.
Marshall thinks that LW changes protocol - same situation is with unicast
general query ... it may take decades for real deployment. (?)
Jari: separate things - if LW changes the protocol, we should say so. But
that is not task of this WG. Characteristics in wireless environment should
be considered where and when affecting the protocol.
Thomas: You say there are no cons to use MLD light, but there are advantages
to use exclude mode in mobility regimes (cf. discussions on mailing list).
Hitoshi: Why a mobile node needs exclude?
Stig: In video conferencing for example, you might want to exclude sources to
preserve bandwidth, I guess.

Unicast MLD Queries.
Stig: Unicast MLD Queries might be supported but who has implemented this?
I suppose there are no routers that have implemented the query part based on
unicast. It would be Interesting to check existing implementations.

<Discussion on charter items>
Stig: Discussed the meaning of tuning IGMP/MLD. My personal opinion is, that
it would be fine to support unicast-based MLD Queries if vendors have
implemented this.
Marshall: Are unicast MLD Qeueries part of the MLD light version?
Hitoshi: The MLD light version does not change this aspect. Should we change
the name of the draft to consider the described optimizations?
Stig: Change the title. We cannot change protocols and nodes (s. charter).
Suresh: You have to think about routers, as well.
Thomas: A BCP contains advisory. You can add a section what to do if unicast
general Query is supported.
Stig: It seems that lightweight MLD is orthogonal to mobility scenarios.
Jari: There are multiple things: Specify exact timer values, may mean guidance;
including the MLD light protocol is profiling.
Stig: I am not sure if this could work or not work.
Marshall: It seems that lightweight MLD really changes the protocol. Similar
to the MLD unicast-based Query, this may introduce problems if there are nodes
that do not support this. It takes decades to deploy updated MLD protocol
versions.
Jari: One have to separate: If MLD light changes protocol, we should state
this. Consider wireless specifics when affecting the protocol.
Stig: I suggest that Hitoshi separates basic parts of the document. A revised
version of the document may be a basis. Additionally, more people should
contribute to this MLD draft.

Next Steps. No formal adoption of this draft for the charter item yet. It was
agreed that the basic part of the draft would be a good basis. More people
agreed to contribute. 

PMIPv6 solution documents.  

Thomas: Presented "Minimal Deployment Option Solution Overview"

Suresh: Presented "PMIPv6 Multicast Support Solution Overview".
Marshall: Is there any aggregation?
Suresh: No.

Seil Jeon: Presented "Mobile Multicasting Support Solution Overview"
Stig: Thomas suggested to merge these protocols. Is this your opinion, as well?
Seil: Yes.

Guang Lu: Presented "Multicast Services Solution Overview".
Marshall: Would the multicast LMA be co-located with the unicast LMA?
Guang: It doesn't have to be physical boxes, but the functionality is
duplicated.
Marshall: Does each location of the LMA have to deploy a multicast LMA, or
is there a central one?
Juan Carlos: No, you can concentrate multicast traffic.
Thomas: You would be bound to one LMA. Otherwise severe handover problems
may occur. It is not correct to say it solves the scaling problem as you add
the avalanche problem to the LMA.
Suresh: There can be multiple LMAs, but you need some way to split. Thus, I
agree mostly to Thomas.
Guang: We do not need one-to-one mapping between unicast and multicast.
Thomas: I don't think the picture is right: You cannot split per group, you
can only split per MAG.

Carlos J. Bernardos: Presented "Multicast Service Delivery Solution Overview"

<Discussion on all the presented proposals>

Carlos: I have a question to Thomas' presentation. Your solution requires
that each MAG sends an MLD Query. What are the cons in terms of signaling
and battery? (2) What will happen if MN is multi-homed (different MAGs),
what happens in the case of handover?
Thomas: (1) Yes, there is MLD signaling, as well as router signaling (regular
PMIP). That's of the same quality (w.r.t. point-to-point links). (2) If the
MN is multi-homed, it has several interfaces, which may distribute traffic.
That's something the MN has to do. It will get traffic twice, this
optimization is out-of-scope and a normal multi-homing 'issue'.
Actually, it depends on the interface selection by the MN. It is not really
related to mobility.
Behcet: Multiple interface selection is out of charter.
Carlos: Agree with Thomas' reply, but not to Behcet comment.
Stig: There are two options: (1) Context-transfer or (2) MLD Query. 
Hitoshi: You cannot do context transfer without protocol modifications.
Stig: Context transfer is out of the charter. But MLD Query is standard
behaviour of MLD routers.
Carlos: Can we have multicast traffic between MAG and LMA?
Stig: The charter says remote subscription. The question is if basic document
leave it optionally.
Kent Leung: Are multicast sources within the scope of the charter?
Behcet: No.
Juan: We have two choices: Avoid convergence on LMA or MAG. Which way we want
to go? Should we optimize service continuity?
Stig : We got two basic solutions: (1) MLD proxy at MAG (and multicast
router if available), (2) Send MLD messages up to the LMA based on tunneling.
The states have to be at LMA or MAG. I prefer the MLD proxy solution 
(personal opinion).
Kent: I Agree with Stig, but when you are doing multicast router scheme ...
       you have states at MAG and LMA.
Guang: Direct router solution: It doesn't fit into the charter. (2) Agree
with similarities of the solutions. We probably don't have a one fit all
solution. Probably, we should evaluate use cases and solutions before we go
ahead?
Thomas: I agree, the direct routing option is not in the charter. But if
there is an operator that has deployed multicast, why not use it?
Guang: But it requires to modify the charter.
Thomas: Probably not if it is an option.
Marshal: When use one or other solution scenarios?
Behcet: charter to come to base solution
Stig: whatever we decide on, this needs not exclude other solutions completely

Behcet: Draft presented does not support IPv4.
Thomas: There are no issues with IGMP proxying. Actually, there is a section
on IPv4 support within the draft.
Stig: All the proposals can easily be extended to IPv4. There is no problem.
Behcet: It is not standard behavior that MLD Query is sent out after link
change. This is an assumption in the draft presented by Thomas.
Stig: I think if a link comes up, a router will send an MLD Query.
Thomas: We have talked with Brian Haberman and he confirmed that MLD Query
will be sent after link change.
Kent: For IGMP it is not standard behaviour that Query is sent when link
comes up.
Stig: We can conclude: The node would not send report on its own. The
question is, how fast the query will be triggered. But that's not a problem.
Carlos: There are other approaches that prevent this timer gap problem.
Juan: That's what we tried to prevent.
Behcet: If we go for the proxy approach, there is the timer gap. Just to
highlight this problem.
Kent: We need layer two indication.
Thomas: This relates to PMIP. It is defined only for point-to-point links.
PMIP needs to be aware of link changes.

Behcet: We should decide between drafts presented by Suresh and Thomas.
Carlos: Are we only decide on this two drafts?
Stig: No, no, we decide on the technologies not on the specific drafts. The
basic solution relies on one of these two alternatives (MLD proxy or non MLD
proxy):
Jouni Korhonen: The non MLD proxy solutions have the problem of double
encapsulation!

Should we consider the techniques described in Krishnan draft? none
Should we consider MLD proxy? 16
How many people are uncertain? 2

Behcet: There is a consensus on proxy approaches.
Stig: We have decided on a (technical) direction to go, not on a particular
draft.

Jouni: Why we hurry up?
Stig: We have to agree on a solution with respect to milestones.
Jari: Basic stuff has to be done to move to the interesting problems.
However, we have not to sacrifice anything if solution space needs further
investigation.

Stig: We continue discussion on the mailing list. Thanks for coming and the
good session.

---

From: Carlos Jesús Bernardos Cano <[email-masked]>
Date: Mon, 16 Nov 2009 23:37:05 +0100

Dear chairs,

IMHO, there are several interesting discussions that took place during
the meeting (e.g., q&a about particular solutions, discussions about the
way to move forward, etc) that are not captured in the posted minutes.

An approach that I've seen other WGs have followed in the past is to use
the recorded audio stream to complete the minutes. I think it would be a
good idea that minute takers and/or chairs use the stream to complete
the minutes. What do others think?

Thanks,

Carlos

-- 
Carlos Jesús Bernardos Cano     http://www.netcoms.net
GPG FP: D29B 0A6A 639A A561 93CA  4D55 35DC BA4D D170 4F67

---

From: Behcet Sarikaya <[email-masked]>
Date: Mon, 16 Nov 2009 15:12:11 -0800 (PST)

Hi Carlos,

----- Original Message ----
> From: Carlos Jesús Bernardos Cano <[email-masked]>
> To: Behcet Sarikaya <[email-masked]>
> Cc: [email-masked]
> Sent: Mon, November 16, 2009 4:37:05 PM
> Subject: Re: [multimob] Minutes
> 
> Dear chairs,
> 
> the recorded audio stream to complete the minutes.

I am not familiar with this being the norm. I have used dime WG style in combining the two minutes taken by Dirk and Matthias.

> I think it would be a
> the minutes. 

If you wish to volunteer to produce a very detailed minutes by listening to the audio recording, you are welcome to do so :).

Regards,

Behcet

---

From: Matthias Waehlisch <[email-masked]>
Date: Tue, 17 Nov 2009 00:24:30 +0100

Hi Behcet,

On Mon, 16 Nov 2009, Behcet Sarikaya wrote:

> I am not familiar with this being the norm. I have used dime WG style in 
> combining the two minutes taken by Dirk and Matthias.
> 
  I think that your combination of our two minutes has resulted in a very 
summarized minute overview. I agree with Stig that you should update the 
posted minutes according to our more detailed notes, or post both the 
minute overview and a more elaborated merger.

Thanks
  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: Mon, 16 Nov 2009 15:25:12 -0800

> the minutes. What do others think?

Carlos, do you think the minutes I sent are sufficient? That was based
on the raw text by our minute takers and should be fairly close to the
audio.

Stig

>> ------------------------------------------------------------------------
>>

---

From: Carlos Jesús Bernardos Cano <[email-masked]>
Date: Tue, 17 Nov 2009 00:31:46 +0100

Hi Stig,

> on the raw text by our minute takers and should be fairly close to the

Yes, I think so. These are more complete and should be enough. Thanks!

Carlos

---

From: Carlos Jesús Bernardos Cano <[email-masked]>
Date: Tue, 17 Nov 2009 00:34:20 +0100

Hi Behcet,

> I am not familiar with this being the norm. I have used dime WG style in combining the two minutes taken by Dirk and Matthias.

Well, it is not the norm, but it has been used in the past (e.g.,
AUTOCONF, IETF 75th) when the initial minutes were not considered
complete enough.

> If you wish to volunteer to produce a very detailed minutes by listening to the audio recording, you are welcome to do so :).

I think that I'd kindly decline your invitation this time :), especially
because the minutes provided by Stig are good enough, IMHO.

Thanks,

Carlos

---

From: Behcet Sarikaya <[email-masked]>
Date: Mon, 16 Nov 2009 15:42:25 -0800 (PST)

Hi Matthias, all,
  Yes, I added original versions of the two minutes and posted the resulting text at:
http://www.ietf.org/proceedings/09nov/minutes/multimob.txt

Have fun :).

Regards,

Behcet

----- Original Message ----
> From: Matthias Waehlisch <[email-masked]>
> Cc: [email-masked]; [email-masked]
> Sent: Mon, November 16, 2009 5:24:30 PM

---

From: Behcet Sarikaya <[email-masked]>
Date: Mon, 16 Nov 2009 15:46:19 -0800 (PST)

Hi Carlos,
  Normal procedure is WG members provide text to add/replace parts of the posted minutes (which of course may be questioned by other people).
  
Regards,

Behcet

----- Original Message ----
> Sent: Mon, November 16, 2009 5:34:20 PM
> > > From: Carlos Jesús Bernardos Cano 
> > > To: Behcet Sarikaya 
> > > Cc: [email-masked]
> > If you wish to volunteer to produce a very detailed minutes by listening to 
> the audio recording, you are welcome to do so :).
>

---

From: Carlos Jesús Bernardos Cano <[email-masked]>
Date: Tue, 17 Nov 2009 00:52:10 +0100

Hi Behcet,

>   Normal procedure is WG members provide text to add/replace parts of the posted minutes (which of course may be questioned by other people).

Fully agree. My proposal was to use the recorded audio stream to help WG
members add/replace parts of the posted minutes, which is fully inline
with your view, I guess.

Basically, my point was that if we need to complete something from the
minutes (that was my opinion considering the first version of the posted
minutes), the audio stream may be a very valuable resource.

Thanks,

Carlos

P.S. I guess this is enough discussion about procedures. Lets focus on
multimob issues :-D