Re: Multicast requirements

Dear all,

As requested we have been working on a proposal for updating current DMM 
Requirements draft, reflecting the work developed in 
"draft-sfigueiredo-multimob-use-case-dmm-03.txt". We were careful to 
follow the expressed concerns, mainly by not impacting the current 
(mostly accepted) draft structure and content.
As such, we propose the following 2 changes:

# Proposal 1 - small update to PS1 #

PS1: Non-optimal routesRouting 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 
using IP multicasting*.


# Proposal 2 - Add a new requirement#

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].


Best regards,
Sérgio & Seil


On 11/12/2012 10:49 PM, Seil Jeon wrote:
> Hi Pete,
>
> That might be one of them we can take on DMM. Imagine, depending on
> deployment of existing IP multicasting standard entities, we can think of
> various use cases as presented in
> http://tools.ietf.org/html/draft-sfigueiredo-multimob-use-case-dmm-03.
> Direct routing cannot be applied in every scenario.
>
> After I came back from the trip, we (me and Sergio) have been working on
> this with priority. After carefully reviewing the requirement from the use
> cases, we'll announce it soon.
>
> Regards,
> Seil
>
> -----Original Message-----
> From: [email protected] [mailto:[email protected]] On Behalf Of Peter
> McCann
> Sent: Monday, November 12, 2012 9:53 PM
> To: Thomas C. Schmidt
> Cc: Stig Venaas; Behcet Sarikaya; [email protected]
> Subject: Re: [DMM] Multicast requirements
>
> In the DMM case my assumption is that the anchor points are closer to the
> access routers and therefore are very likely to be in the same
> administrative domain.  In these cases, joining the multicast group directly
> from the access router gives you the same access to the same multicast
> streams and so tunneling the multicast packets won't be necessary.
>
> -Pete
>
> Thomas C. Schmidt wrote:
>> Dear Pete,
>>
>> multicast mobility management is a route adaptation problem. As in the
>> unicast case, mobility can only be treated by routing dynamics in
>> trivial cases (re-connect of a tunnel, re-association with next hop).
>> Otherwise it is unwise to delegate mobility adaptation to routing
>> protocols (-> OSPF, BGP ...).
>>
>> Accordingly, if DMM distributes mobility operations, handover
>> management should foresee easy interconnects to previous distribution
>> trees - both for receivers and for mobile multicast sources.
>>
>> I guess, if DMM people are careful, this is not a world-class item and
>> can be treated along the lines of unicast solutions - an isolated
>> multicast protocol treatment (as has been previously proposed from
>> MULTIMOB folks) seems inappropriate. In core PMIP, multicast treatment
>> has turned out to work out simply (-> RFC6224).
>>
>> Thus my argument: talk to the multicast guys before adopting a
>> solution ... and make the rest an easy game.
>>
>> Cheers,
>>
>> Thomas
>>
>> On 12.11.2012 21:39, Peter McCann wrote:
>>> jouni korhonen wrote:
>>>> Folks,
>>>>
>>>> This mail is to kick off the discussion on multicast requirement(s)
>>>> for the draft-ietf-dmm-requirements-02 document. I hope we can nail
>>>> down the essential multicast requirement(s) as soon as possible.
>>> To me, multicast in a DMM environment means joining multicast groups
>>> directly from access routers.  It means re-joining the multicast tree
>>> from a new access router after handover.  I would hope that we can
>>> use existing MLD protocols between the MN and its first hop AR to
>>> accomplish this.
>>>
>>> -Pete
>>>
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>
>
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