There are 3 proposals for multicast requirements. Before comparing
these proposals, let us understand what are the problems first. Two
problem statements have been proposed:
PS1 (revised): Non-optimal routes
Routing via a centralized anchor often results in a longer route. The
problem is especially manifested when accessing a local server or
servers of a Content Delivery Network (CDN), *or when receiving /
sending IP multicast packets*.
PS6: Duplicate multicast traffic
IP multicast distribution over architectures using IP mobility
solutions may lead to convergence of duplicated multicast
subscriptions towards the tunnel's downstream entity (e.g. MAG in
PMIPv6). Concretely, when multicast subscription for individual
mobile nodes is coupled with mobility tunnels, duplicate multicast
subscription(s) is prone to be received through different upstream
paths. This problem is potentially more severe in a distributed
mobility environment [draft-sfigueiredo-multimob-use-case-dmm-03].
Then, let us see whether all the 3 REQ proposals have the same
intention. In the following, I rephrase them to highlight their
similarities.
REQ7.1: Flexible multicast distribution
DMM solutions should be compatible with flexible multicast
distribution scenario. Etc.
The Motivation is to allow flexibility in (enable) multicast solutions
to solve the problems PS1 and PS6 as explained in use cases already
presented and discussed in multimob wg.
REQ7.2:
DMM solutions should enable solutions to support multicast traffic.
(Original wording was "The DMM (unicast) solution MUST be specified in
such a way that it can be extended to also support multicast traffic."
I rephrase it to highlight the similarity with the other proposals and
also changed the must to should.)
REQ7.3:
DMM solutions should enable solutions to support multicast services.
Original wording was "DMM solutions should support multicast services
... etc. Given that it is the scope of multimob and not dmm wg to
provide the multicast solution, I think "support" here means "enable"
solutions to be developed (by multimob).
Similarity and subtle differences: Both REQ7.2 and REQ7.3 want to
enable multicast services. Yet the explanation in REQ7.1 seems to
indicate not just to enable any one multicast solution but also needs
the flexibility in multicast solution. Not all multicast solutions are
the same. Some of them results in PS1 or PS6.
Are there any are essential differences between:
In REQ7.1, DMM solutions should be compatible with flexible multicast
distribution scenario, etc.
Versus
DMM solutions should enable multicast services which are compatible
with multicast distribution scenario, etc.
H Anthony Chan
*From:*[email protected] [mailto:[email protected]] *On Behalf
Of *Seil Jeon
*Sent:* Monday, November 19, 2012 5:15 AM
*To:* [email protected]
*Cc:* [email protected]
*Subject:* Re: [DMM] Multicast requirements
Hi Pierrick,
I've many times thought about your question. I would say how
effectively should we deploy/support multicast over distributed
mobility rather than distributed mobile multicast. As a result, you
can find this deployment use case and gap analysis at
http://tools.ietf.org/html/draft-sfigueiredo-multimob-use-case-dmm-03
presented in multimob several times.
In unicast DMM, main innovation is to distribute the anchor function
at many access routers from single core. Following architectural
concept of DMM, flexible multicast distribution is one of multicast
requirement resulted from the draft described above.
REQ8: Flexible multicast distribution
"DMM solutions SHOULD be compatible with flexible multicast
distribution scenarios. This flexibility enables different IP
multicast flows with respect to a mobile host to be managed (e.g.,
subscribed, received and/or transmitted) using multiple endpoints".
Motivation: The motivation for this requirement is to enable
flexibility in multicast distribution. The multicast solution may
therefore avoid having multicast-capable access routers being
restricted to manage all IP multicast traffic relative to a host via a
single endpoint (e.g. regular or tunnel interface), which would lead
to the problems described in PS1 and PS6.
PS6: Duplicate multicast traffic
IP multicast distribution over architectures using IP mobility
solutions may lead to convergence of duplicated multicast
subscriptions towards the tunnel's downstream entity (e.g. MAG in
PMIPv6). Concretely, when multicast subscription for individual mobile
nodes is coupled with mobility tunnels, duplicate multicast
subscription(s) is prone to be received through different upstream
paths. This problem is potentially more severe in a distributed
mobility environment [draft-sfigueiredo-multimob-use-case-dmm-03].
Regards,
Seil
*From:*[email protected] [mailto:[email protected]]
*Sent:* Monday, November 19, 2012 8:55 AM
*To:* '[email protected]'; [email protected];
[email protected]
*Cc:* [email protected]
*Subject:* RE: [DMM] Multicast requirements
Hi all,
I tend to agree with Georgious, however I still do not figure out what
is the use-case for distributed mobile multicast (other than academic
considerations)? Can someone give concrete example?
I haven't real all messages from this thread. So, maybe I missed
important points.
BR,
Pierrick
*De :*[email protected] <mailto:[email protected]>
[mailto:[email protected]] *De la part de* [email protected]
<mailto:[email protected]>
*Envoyé :* samedi 17 novembre 2012 13:01
*À :* [email protected] <mailto:[email protected]>;
[email protected]
<mailto:[email protected]>
*Cc :* [email protected] <mailto:[email protected]>
*Objet :* Re: [DMM] Multicast requirements
Hi all,
I also agree that the DMM solution should somehow consider muticast
deployment. However, I do not thnk that the DMM WG is the right WG to
provide the multicast based DMM solution!
One alternative solution will be to have a multicast requirement that
emphasizes the need of having extensibility hooks (possibilities) that
can be used later on by the multimob WG to provide a
a multicast enabled DMM solution!
So a requirement that specifies something like the following could be
used for this purpose:
"The DMM (unicast) solution MUST be specified in such a way that it
can be extended to also support multicast traffic."
Best regards,
Georgios
------------------------------------------------------------------------
*Van:*[email protected]
<mailto:[email protected]>[[email protected]] namens Seil Jeon
[[email protected]]
*Verzonden:* vrijdag 16 november 2012 22:25
*To:* 'Zuniga, Juan Carlos'
*Cc:* [email protected] <mailto:[email protected]>
*Onderwerp:* Re: [DMM] Multicast requirements
Hi Juan,
I've been looked at changed flow of your proposed text but sorry now
that my
comment is posted.
At first time, I couldn't make sure however, on hearing Stig's
description,
it seems quite reasonable at the first step, not giving any
restrictions but
leaving some-specific for the DMM solution it does not support multicast.
On the other hand, it remains at a basic stage for the DMM solution to
support multicast.
So I think additional requirements need to be made for the DMM solution,
accordingly. But of course, this should not also give any specific
limitation and restriction but should be made towards the direction not
limiting the benefits provided by distributed deployment.
I hope to get more comments on this.
Regards,
Seil
-----Original Message-----
From: [email protected]
<mailto:[email protected]>[mailto:[email protected]] On Behalf Of
Zuniga, Juan Carlos
Sent: Friday, November 16, 2012 8:14 PM
To: Stig Venaas; [email protected] <mailto:[email protected]>
Subject: Re: [DMM] Multicast requirements
> -----Original Message-----
> From: Stig Venaas [mailto:[email protected]]
> Sent: Friday, November 16, 2012 3:01 PM
> To: jouni korhonen
> Cc: [email protected] <mailto:[email protected]>; Zuniga, Juan
Carlos; Konstantinos Pentikousis;
> Peter McCann; [email protected] <mailto:[email protected]>
> Subject: Re: [DMM] Multicast requirements
>
> On 11/15/2012 3:17 AM, jouni korhonen wrote:
> >
> > On Nov 15, 2012, at 1:03 AM, Behcet Sarikaya wrote:
> >
> >>
> >> I think we are reading too much into multicast and unicast should
be
> >> designed in an integrated manner.
> >>
> >> The fact is that multicast is considered as an area of
> specialization,
> >> it requires knowledge of very different protocols than we are
> >> accustomed to in mobility.
> >
> > "Requirement: DMM solutions SHOULD support multicast services. If a
> specific DMM solution does not support multicast services, an
> explanation MUST be provided."
>
> This sounds good to me.
>
> The main thing I want to achieve is what was describes as motivation
> earlier in this thread. Multicast should at least be considered when
> looking into DMM solutions, and not just an afterthought once the
> solution is decided.
>
> Stig
[JCZ] I fully agree with this. That was the intention of the proposed
text.
Regards,
Juan Carlos
>
> > To me that reads basically "do not break foundations for multicast
> unless you have a valid & documented reason for it". If we look e.g.
> into RFC625 multicast wording that is there very briefly but gives a
> hint to a developer where to head to. That is the level I would expect
> DMM documents should aim to.
> >
> > - Jouni
> >
> >
> >> Let dmm deal with its current charter that does not include a word
> of
> >> multicast and if everything goes well we can come back and discuss
> dmm
> >> multicast.
> >>
> >> Regards,
> >>
> >> Behcet
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