Re: [spring] Updating the SPRING WG Charter

[Stewart Bryant <[e-mail]>]

Hi Robert,

OK, so I understand this a bit more.

Yes, we could introduce a m/c tree in the middle of the network and have 
the leaves terminate in anything. That would include an SR unicast path 
and/or a new m/c tree or any combination thereof. What you have to do is 
to place the correct binding SID at the leaf of the tree which of course 
would be unique to that leaf, and identified by the m/c tree it arrived on.

So by adding in state through a generalised Binding SID mechanism we can 
build a full multicast system strictly within SR.

Sounds like it needs to be in charter.

- Stewart


On 19/06/2018 14:39, Robert Raszuk wrote:
> Hi Stewart,
>
> Nope that would be incorrect assumption.
>
> Replication anchors would be where topologically it makes sense. And 
> there may not be at all any multicast trees those subject flows would 
> need to traverse. It is just about efficiency in content distribution.
>
> Regards,
> R.
>
> On Tue, Jun 19, 2018 at 3:36 PM, Stewart Bryant 
> <[e-mail] <mailto:[e-mail]>> wrote:
>
>     For clarification:
>
>     Can I assume that we are talking about replication at ingress to a
>     series of  unicast SR paths each to an installed multicast tree
>     close to egress?
>
>     - Stewart
>
>
>     On 10/06/2018 10:58, Robert Raszuk wrote:
>>     Hey Sasha,
>>
>>     100% agree with your last post. Very glad to see your support for
>>     spray/fan-out or if you will
>>     static MDTs to be in scope of SPRING.
>>
>>     Based on number of WG members input expressed both at the meeting
>>     and on the list  I hope
>>     proposed SPRING charter will be updated soon to reflect that.
>>
>>     Cheers,
>>     R.
>>
>>     ​PS. Btw - I am also ok that ingress replication is not relevant
>>     to SPRING as it essentially happens at the
>>     ingress to the domain. ​
>>
>>
>>
>>     On Sun, Jun 10, 2018 at 7:39 AM, Alexander Vainshtein
>>     <[e-mail]
>>     <mailto:[e-mail]>> wrote:
>>
>>         Robert,
>>
>>         First of all, I did not say that your quote was inaccurate. I
>>         apologize for possible misperception.
>>
>>         Second, I believe that spray or fan-out (meaning support of
>>         externally computed static MDTs) in SR-MPLS is a relevant
>>         focus area for the future WG work. Of course the solution
>>         must be aligned with the SPRING and MPLS architecture, and
>>         this imposes additional restrictions on how such a solution
>>         would look.
>>
>>         Last but not least, I have differentiated (from my first
>>         email on this thread) */ingress replication/* *in SR* from
>>         the more generic *multicast support *in SR:
>>
>>         -The latter is quite acceptable to me
>>
>>         -The former, IMHO, should be left out of scope.
>>
>>         Hope this helps to clarify my position.
>>
>>         Regards, and, again, apologies for possible misinterpretation.
>>
>>         Sasha
>>
>>
>>
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