Re: [spring] The SPRING WG has placed draft-voyer-spring-sr-replication-segment in state "Candidate for WG Adoption"

[Greg Mirsky <[e-mail]>]

Dear All,
I concur with Sasha and John. Intended ingress replication of a particular
flow, though using a unicast destination address, is still a multicast.

Regards,
Greg

On Thu, Nov 14, 2019 at 5:36 AM John E Drake <jdrake=
[e-mail]> wrote:

> Robert,
>
> As Sasha and I have indicated, your position is your own and is not
> consistent with the majority of work on this topic.  I’m fine w/ agreeing
> to disagree.
>
> John
>
> Sent from my iPhone
>
> On Nov 14, 2019, at 2:57 AM, Robert Raszuk <[e-mail]> wrote:
>
> 
> John,
>
> > Your claim that ingress replication is not multicast is, at best, a
> stretch.
>
> I use a very basic and simple rule of thumb ... if address of my packet is
> a multicast address then it is multicast if not it is unicast.
>
> Ref:
> https://www.iana.org/assignments/multicast-addresses/multicast-addresses.xhtml
> <https://urldefense.com/v3/__https://www.iana.org/assignments/multicast-addresses/multicast-addresses.xhtml__;!8WoA6RjC81c!QFbPjRVo7hB9622FCxHnivS8PVicSm5TCW9kaF-KRqhC3G7uLL0tCrGUUxL2sAQ$>
>
>
> Solution as described in draft-voyer-spring-sr-replication-segment does
> not seems to be requiring multicast addresses hence it is applicable to
> pure unicast networks.
>
> Thx,
> Robert.
>
>
> On Wed, Nov 13, 2019 at 10:20 PM John E Drake <[e-mail]> wrote:
>
>> Robert,
>>
>>
>>
>> I’m sorry for the confusion.  My only point was that MVPN provides the
>> reference architecture for dealing w/ multicast using a multiplicity of
>> tunnel types in a consistent manner, as Sasha alluded to in his mention of
>> PMSI.  Your claim that ingress replication is not multicast is, at best, a
>> stretch.
>>
>>
>>
>> Yours Irrespectively,
>>
>>
>>
>> John
>>
>>
>>
>>
>>
>> Juniper Business Use Only
>>
>> *From:* Robert Raszuk <[e-mail]>
>> *Sent:* Wednesday, November 13, 2019 3:55 PM
>> *To:* John E Drake <[e-mail]>
>> *Cc:* Alexander Vainshtein <[e-mail]>;
>> [e-mail];
>> [e-mail]; <
>> [e-mail]> ([e-mail]) <
>> [e-mail]>
>> *Subject:* Re: [spring] The SPRING WG has placed
>> draft-voyer-spring-sr-replication-segment in state "Candidate for WG
>> Adoption"
>>
>>
>>
>> Hi John,
>>
>>
>>
>> > Further, ingress replication has been part of MVPN since forever.
>>
>>
>>
>> Just curious how is this at all relevant for this discussion ?
>>
>>
>>
>> Do I have to roll out MVPN monster to split my unicast UDP stream to few
>> receivers at selected network point ?
>>
>>
>>
>> And last but not least who said this is at all related to "ingress
>> replication" ??? Ingress to p2mp segment can be at any SR midpoint in the
>> network. Are you suggesting to run MVPN apparatus with manual tree building
>> ? Whow :)
>>
>>
>>
>> Thx,
>>
>> R.
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> On Wed, Nov 13, 2019 at 9:40 PM John E Drake <[e-mail]> wrote:
>>
>> Hi,
>>
>>
>>
>> I think Sasha has a valid point.  Further, ingress replication has been
>> part of MVPN since forever.
>>
>>
>>
>> Yours Irrespectively,
>>
>>
>>
>> John
>>
>>
>>
>>
>>
>> Juniper Business Use Only
>>
>> *From:* spring <[e-mail]> *On Behalf Of *Alexander
>> Vainshtein
>> *Sent:* Wednesday, November 13, 2019 9:26 AM
>> *To:* Robert Raszuk <[e-mail]>
>> *Cc:* [e-mail];
>> [e-mail]; <
>> [e-mail]> ([e-mail]) <
>> [e-mail]>
>> *Subject:* Re: [spring] The SPRING WG has placed
>> draft-voyer-spring-sr-replication-segment in state "Candidate for WG
>> Adoption"
>>
>>
>>
>> Robert,
>>
>> Lots of thanks for a prompt response.
>>
>>
>>
>> You seem to imply that a multicast distribution tree that is built, say,
>> by an SDN controller and used, say, to act as a PMSI in the mVPN
>> application, is not really a multicast.  Personally I disagree, but this is
>> a matter of taste and terminology.
>>
>>
>>
>> What looks unambiguous to me is that:
>>
>>    - The WG charter explicitly mentions ingress replication as one of
>>    “new types of segments mapping to forwarding behavior” that “may require
>>    architectural extensions”
>>    - The current architecture document does not cover any such segment
>>    type (whether because such segments have been considered as related to
>>    multicast by the authors, or for some other reason is not all that
>>    important. )
>>
>> Therefore my concern remains unresolved regardless of whether ingress
>> replication is or is not formally considered as multicast.
>>
>>
>>
>> Regards,
>>
>> Sasha
>>
>>
>>
>> Office: [phone]
>>
>> Cell:      [phone]
>>
>> Email:   [e-mail]
>>
>>
>>
>> *From:* Robert Raszuk <[e-mail]>
>> *Sent:* Wednesday, November 13, 2019 4:15 PM
>> *To:* Alexander Vainshtein <[e-mail]>
>> *Cc:* <[e-mail]> ([e-mail]) <
>> [e-mail]>;
>> [e-mail];
>> [e-mail]
>> *Subject:* Re: [spring] The SPRING WG has placed
>> draft-voyer-spring-sr-replication-segment in state "Candidate for WG
>> Adoption"
>>
>>
>>
>> Sasha,
>>
>>
>>
>> If I have some content and I send it to you and your neighbour as two
>> unicast streams am I suddenly doing multicast ?
>>
>>
>>
>> IMHO N number of replicated unicasts is still not a multicast.
>>
>>
>>
>> Multicast in my definition requires  multicast groups, receiver joins,
>> tree building protocols etc ... and this draft does not suggest any of
>> this. IN contrast it just describes how can we have p2mp unicast
>> distribution ... call it fan out node.
>>
>>
>>
>> Thx,
>> R.
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> On Wed, Nov 13, 2019 at 12:42 PM Alexander Vainshtein <
>> [e-mail]> wrote:
>>
>> Hi all,
>>
>> I have a question regarding adoption of
>> draft-voyer-sr-spring-replication-segment as a SPRING WG document.
>>
>>
>>
>> These concerns are based on the following:
>>
>> 1.       This draft (both based on its title and on its content) deals
>> with local (in the Root node) ingress replication which, in its turn, is
>> one of the issues that could be used for delivery of multicast.
>>
>> 2.       Local ingress replication is mentioned in the SPRING WG Charter
>> as one of the “New types of segments mapping to forwarding behavior”.
>> The charter further says that “Any of the above <*Sasha: New types of
>> segments*> may require architectural extensions”
>>
>> 3.       The current (and, AFAIK, the only existing) Segment Routing
>> Architecture document (RFC 8402
>> <https://urldefense.com/v3/__https:/clicktime.symantec.com/34qM9QogJnh1eY5nZPXYAkA6H2?u=https*3A*2F*2Ftools.ietf.org*2Fhtml*2Frfc8402__;JSUlJSU!8WoA6RjC81c!TeDGZsCZsxVU3U1A-_hQaYhZsmLZFF4oF-lGSpNnOmTa-zUl6jfGkGEUOvwkLSU$>)
>> explicitly states in Section 6 that “Segment Routing is defined for
>> unicast. The application of the source-route concept to Multicast is not in
>> the scope of this document”.
>>
>> The combinations of observations above strongly suggests to me that a
>> document defining multicast-related extensions of segment routing
>> architecture should be very useful (if not mandatory) for progressing the
>> Replication Segment draft. From my POV the Replication Segment draft is not
>> (and is not intended to be) such a document.
>>
>>
>>
>> I wonder if there is an intention to produce such a document in the
>> timeframe that could be relevant for discussion of the Replication Segment
>> draft.
>>
>>
>>
>> Nothing in this message should be interpreted as my objection to (or
>> support of) adoption of the Replication Segment draft as a WG document *per
>> se*.
>>
>> Bit I find it difficult to take a position any which way without a clear
>> and commonly agreed upon framework for multicast in segment routing.
>>
>>
>>
>> Regards,
>>
>> Sasha
>>
>>
>>
>> Office: [phone]
>>
>> Cell:      [phone]
>>
>> Email:   [e-mail]
>>
>>
>>
>> -----Original Message-----
>> From: spring <[e-mail]> On Behalf Of IETF Secretariat
>> Sent: Tuesday, November 12, 2019 7:06 PM
>> To: [e-mail];
>> spring-chairs@ietf..org; [e-mail]
>> Subject: [spring] The SPRING WG has placed
>> draft-voyer-spring-sr-replication-segment in state "Candidate for WG
>> Adoption"
>>
>>
>>
>>
>>
>> The SPRING WG has placed draft-voyer-spring-sr-replication-segment in
>> state Candidate for WG Adoption (entered by Bruno Decraene)
>>
>>
>>
>> The document is available at
>>
>>
>> https://clicktime.symantec.com/3EMJRgfTdX6UyWKGnMPiVwZ6H2?u=https%3A%2F%2Fdatatracker.ietf.org%2Fdoc%2Fdraft-voyer-spring-sr-replication-segment%2F
>> <https://urldefense.com/v3/__https:/clicktime.symantec.com/3EMJRgfTdX6UyWKGnMPiVwZ6H2?u=https*3A*2F*2Fdatatracker.ietf.org*2Fdoc*2Fdraft-voyer-spring-sr-replication-segment*2F__;JSUlJSUl!8WoA6RjC81c!TeDGZsCZsxVU3U1A-_hQaYhZsmLZFF4oF-lGSpNnOmTa-zUl6jfGkGEUHVCWfyU$>
>>
>>
>>
>> Comment:
>>
>> IPR call:
>>
>>
>> https://clicktime.symantec.com/3KG7A2qM3Xf2eqDctGju1e66H2?u=https%3A%2F%2Fmailarchive.ietf.org%2Farch%2Fmsg%2Fspring%2F_stJjBM5K6vr7QYw0HRKf-z0_us
>> <https://urldefense.com/v3/__https:/clicktime.symantec.com/3KG7A2qM3Xf2eqDctGju1e66H2?u=https*3A*2F*2Fmailarchive.ietf.org*2Farch*2Fmsg*2Fspring*2F_stJjBM5K6vr7QYw0HRKf-z0_us__;JSUlJSUlJQ!8WoA6RjC81c!TeDGZsCZsxVU3U1A-_hQaYhZsmLZFF4oF-lGSpNnOmTa-zUl6jfGkGEUfVccUWU$>
>>
>>
>>
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