RE: CRH and RH0

["Ketan Talaulikar (ketant)" <[e-mail]>]

Hi Bob,

Please check inline

-----Original Message-----
From: ipv6 <[e-mail]> On Behalf Of Bob Hinden
Sent: 13 May 2020 21:46
To: 6man <[e-mail]>
Cc: Bob Hinden <[e-mail]>
Subject: Re: CRH and RH0

Gentlepeople,

IPv6 routing headers starting with RFC1883 published in 1995 used the term “segments” to identify elements in the list of addresses.   In that sense, all IPv6 routing headers do some form of segment routing.  It’s a generic term that has been around for 25 years.

I think the underlying question with CRH is does it conflict with what is being done in the Spring w.g.
[KT] IMHO we first need to understand what truly this new CRH (standalone ?) proposal is all about. The draft-bonica-6man-comp-rtg-hdr-13 seems to me like just the tip of an iceberg and not fully specified while previous versions provided a better picture in the SRm6 context.

To my thinking, what is being done in Spring is an architecture for distributing information that can be used to create source routes for SRH (RFC8754).  
[KT] Spring is defining the Source Routing architecture. It started with problem statement (RFC7855), use-cases (RFC8354) then the architecture (RFC8402) that also gave requirements for both data-planes (incl RFC8754) and also control plane for signalling and distribution of information.

 Anything that relies on that set of Spring routing protocols is part of the working being done in Spring.
[KT] The "Spring routing protocols" are nothing but OSPF, ISIS, BGP, PCEP, ..... These same protocols are going to be used for the distribution and advertisement of the CRH-FIB (ref https://tools.ietf.org/html/draft-bonica-6man-comp-rtg-hdr-13#section-4). I think this is what some of the other comments have eluded to.


Likewise, to my thinking I don’t think that means that all new IPv6 routing headers conflict with the work being done in the Spring w.g.
[KT] Perhaps not and perhaps it would depend on the overall architecture since there were other new source RHs proposals also on the table? We have the precedence of RFC6275 and RFC6554. These RHs had WGs (similar to Spring) that defined their use-cases, architecture that covered applicability and requirements. Post that their respective RHs were specified. On the same lines SRH (RFC8754) was done in collaboration with Spring.

Thanks,
Ketan

Bob


> On May 13, 2020, at 8:55 AM, Robert Raszuk <[e-mail]> wrote:
> 
> Ron,
> 
> Oh - haven't we established just yesterday that you will not be referencing RH0 any longer with CRH proposal  ?
> 
> It's like you are trying to build a vehicle  .. it has wheels, steering and even seats (no engine and no belts for now). But you keep insisting - it is not a car.
> 
> See if you put normative reference to segment routing up to version -10 then suddenly drop it with no major change to the body of the draft the intentions are just obvious:
> 
> 13.  References
> 
> 
> 
> 13.1.  Normative References
> 
> 
>    [
> I-D.bonica-spring-srv6-plus
> ]
>               Bonica, R., Hegde, S., Kamite, Y., Alston, A., Henriques,
>               D., Jalil, L., Halpern, J., Linkova, J., and G. Chen,
>               "Segment Routing Mapped To IPv6 (SRm6)",
> draft-bonica-
> spring-srv6-plus-06 (work in progress), October 2019.
> 
> REF: https://tools.ietf.org/html/draft-bonica-6man-comp-rtg-hdr-10
> 
> On Wed, May 13, 2020 at 5:41 PM Ron Bonica <[e-mail]> wrote:
> Robert,
> 
> 
> 
> Oh, btw. RH0 had a “Segments Left” field. Because it talked about segments, would you like to claim that it was also SR?
> 
> 
> 
>                                                                            Ron
> 
> 
> 
> 
> 
> Juniper Business Use Only
> From: Ron Bonica
> Sent: Wednesday, May 13, 2020 11:40 AM
> To: Robert Raszuk <[e-mail]>
> Cc: Bob Hinden <[e-mail]>; 6man <[e-mail]>
> Subject: RE: CRH and RH0
> 
> 
> 
> Robert,
> 
> 
> 
> So, you are really sure that these people don’t exist. Would you like to make a more explicit statement?
> 
> 
> 
>                                                                   Ron
> 
> 
> 
> 
> 
> Juniper Business Use Only
> From: Robert Raszuk <[e-mail]>
> Sent: Wednesday, May 13, 2020 11:22 AM
> To: Ron Bonica <[e-mail]>
> Cc: Bob Hinden <[e-mail]>; 6man <[e-mail]>
> Subject: Re: CRH and RH0
> 
> 
> 
> [External Email. Be cautious of content]
> 
> 
> 
> Hi Ron,
> 
> 
> 
> >  Are you questioning whether that statement is true?
> 
> 
> 
> Yes. Especially this point: " Are not interested in SR"
> 
> 
> 
> Your draft only talks about SIDs and segments so no matter how you call it the core purpose is segment routing.
> 
> 
> 
> Take care,
> R.
> 
> 
> 
> On Wed, May 13, 2020 at 5:13 PM Ron Bonica <[e-mail]> wrote:
> 
> Robert,
> 
> 
> 
> At the interim meeting, I said that there are IPv6 operators who:
> 
> 
> 
> ·         Want CRH
> 
> ·         Are not interested in SR
> 
> ·         Are averse to SRv6
> 
> 
> 
> Are you questioning whether that statement is true?
> 
> 
> 
>                                                           Ron
> 
> 
> 
> 
> 
> 
> 
> Juniper Business Use Only
> From: Robert Raszuk <[e-mail]>
> Sent: Wednesday, May 13, 2020 3:22 AM
> To: Ron Bonica <[e-mail]>
> Cc: Bob Hinden <[e-mail]>; 6man <[e-mail]>
> Subject: Re: CRH and RH0
> 
> 
> 
> [External Email. Be cautious of content]
> 
> 
> 
> Hi Ron,
> 
> 
> 
> Given that it is only fifteen pages long, I suspect that progressing it would be less work than arguing about whether to progress it.
> 
> 
> 
> Sometimes committing a bit more work yields much better results in the long run ...
> 
> 
> 
> So it is clear that you are not just trying to fix suboptimalities of IPv6 encoding out of the woods. The goal is clear to get this in and use it as a hook to show in SPRING and other routing WGs in IETF that since you have CRH accepted as a WG docs in 6man other groups should follow along and work on SRm6 encodings.
> 
> 
> 
> The mapping plane between SIDs and labels is already in place in SR-MPLS. Just changing few bit here and there does not make new proposal to stand on its own.
> 
> 
> 
> I think it has been clearly stated by 6man chairs and AD that any work on SRm6 can be taken on only after SPRING WG accepts the main concept and adopts the main doc as a WG item.
> 
> 
> 
> So I recommend we go via this proper path with the full picture in mind and the ultimate objective for CRH.
> 
> 
> 
> Best regards,
> 
> R.
> 
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>