Re: Adoption call criteria for CRH? [was: Re: CRH and RH0]

["Zafar Ali (zali)" <[e-mail]>]

Hi John,

Re: I think it would be much more productive, not to mention less unpleasant, for the WG to focus on the technical merits of the proposal.

Here is a partial list of issues.

Robert "Drawback of Mapping table"
https://mailarchive.ietf.org/arch/msg/ipv6/g2vrwFO-cjYX0ZeiMxqjWNGfkUU/

Ketan: "All segment types used are as defined in SR architecture RFC8402 (read poor man's job to distance from SRm6)"
https://mailarchive.ietf.org/arch/msg/ipv6/5jDdun2yzwnsJtJE1PzVvj1bjjQ/

Fengwei Qin: "security concerns"
https://mailarchive.ietf.org/arch/msg/ipv6/Vzcojf2mFXdrqW5OYoXf8iwNatQ/

Jingrong: "Limited domain scope and security concerns"
https://mailarchive.ietf.org/arch/msg/ipv6/QyaRQAjPoRExJGWLXaSXWHcMDdQ/

Robert: "How other functions like TI-LFA, uloop avoidance are performed"
https://mailarchive.ietf.org/arch/msg/ipv6/7_aEF5M6owrIqb3t3BNFdCSZ3jM/

Darren: "use-case beyond SRm6"
https://mailarchive.ietf.org/arch/msg/ipv6/emQ3Sj_l4fWXErZY_nhQAbYxr5Y/

Robert: "need for CRH-FIB on all nodes"
https://mailarchive.ietf.org/arch/msg/ipv6/IXlGxvjBBKvTMTA12UaX8jHqQNw/

Shuping: "How to support VPN and HW inefficiency for VPN in DOH and segments in RH."
https://mailarchive.ietf.org/arch/msg/ipv6/aO0MdyDZci2k58cV0W0gzoa1o-c/

Ketan: "Need for clarification for CRH "standalone" proposal"
"https://mailarchive.ietf.org/arch/msg/ipv6/rCZ0HcH009qq4uW4m5VxkT5twNg/"

Robert: "operation complexity"
https://mailarchive.ietf.org/arch/msg/ipv6/LGnbYIv6B4ZoEKrsGp4RHRyO1pA/

Zafar "how to debug the mapping table entry"
During 6man interim session

Darren "clarification for "standalone" CRH architecture use"
https://mailarchive.ietf.org/arch/msg/ipv6/L8kVLCuxNBptiI2cONI32U8jjGM/

Ketan: "CRH is not source routing of RFC791 (use of adj SID and prefix SID RFC8402)"
https://mailarchive.ietf.org/arch/msg/ipv6/Xli0zIUZa53nSbBniOdiRviToqM/

Dan V provided the following list of open issues.

Robert Raszuk on the many extensions required by CRH (IGP, BGP, OAM) https://mailarchive.ietf.org/arch/msg/spring/_V8dsQOeRTuK2r7Lfi77bgICqhE
Robert Raszuk and Dirk Steinberg on CRH being a poor re-engineering of SR-MPLS over IP/UDP
Robert: https://mailarchive.ietf.org/arch/msg/spring/6bdX_gb47uFYnd6ytwFLPYxXCYo
Dirk: https://mailarchive.ietf.org/arch/msg/spring/6Bm4nN5ah8rFb7VutexK30kRUPM
Dan Voyer reminding that SRv6 is a mature technology (deployments, long IETF work), as opposed to CRH https://mailarchive.ietf.org/arch/msg/spring/OB1l41EhhUu8x8XEnKaBTdczDj4
Zhibo Hu on the many advantages of SRv6 https://mailarchive.ietf.org/arch/msg/spring/D7IFJakb5Ew2iMXUfvf1wub7arQ
Cheng Li expressing concerns on the dataplane performance of CRH https://mailarchive.ietf.org/arch/msg/spring/XK0F40oEuZv-3ule-X5685d_6Mc
Zafar summarizing the main issues of CRH https://mailarchive.ietf.org/arch/msg/spring/wFDK_Be7lEt4s191m61WdUOEzL4
Wim Henderickx  https://mailarchive.ietf.org/arch/msg/spring/nX5-1rdXKOw6ks73VYfwvn7iaI8
Darren Dukes  https://mailarchive.ietf.org/arch/msg/spring/v8UAgBGQ0yp0VBwGkZ3RwzH1MME

Thanks

Regards … Zafar

From: John Scudder <[e-mail]>
Date: Friday, May 15, 2020 at 2:56 PM
To: "Zafar Ali (zali)" <[e-mail]>
Cc: "[e-mail]" <[e-mail]>, "[e-mail]" <[e-mail]>, "[e-mail]" <[e-mail]>
Subject: Re: Adoption call criteria for CRH? [was: Re: CRH and RH0]

There are a number of messages following this same “CRH is really SR and SR is not 6man’s business” template; I’ll reply to just Zafar’s but I think the overall point applies to all of them. (The overall point can be summed up as “no, it isn’t really SR”.)

SRm6 was (and is, for that matter) a proposed Segment Routing technology. The proper place for its discussion is in SPRING. What Ron tells us is that subsequent to drafting of SRm6, he realized that the underlying encapsulation technique has useful application independent of SRm6 or SR in general. This should be completely unsurprising to people versed in SR; after all, SR is one particular architecture applied on top of MPLS and IPv6, and absolutely nobody is asserting those technologies are actually SR.

There's a long history both within and outside the IETF of a technology being initially pursued for one reason, and then extended or even completely repurposed into another. This is the essence of invention. The example nearest and dearest to my heart is BGP of course. It was invented as a humble Internet routing protocol, but it’s now used for quite a number of different things (and let’s please not rathole on whether that’s a good thing or a bad thing, eh?). To take another example entirely outside the IETF domain, Teflon was discovered by a DuPont chemist trying to develop a new refrigerant. [1] I don’t think anyone thinks Teflon is worthless because it’s not being used as a refrigerant. That kind of argument is equally fallacious with respect to CRH.

As for "It is clear to all that the current draft and adoption request is an attempt to circumvent the standard practice”, do you really want to go there? First of all, it’s not clear to all: I’m a member of the class “all”, this is not clear to me, Q.E.D. the assertion is false. There’s another example, quite recently, of discussion in this group where it was asserted that someone was “obviously” acting in bad faith; I’m referring to the novel interpretation of what “destination” means in RFC 8200. In the end this was resolved (roughly resolved anyway) by one camp stating, hand on heart, that they sincerely believe their reading is accurate, and the others accepting — or at least accepting that they can’t refute — that statement. Unless you have a way of seeing into another person’s soul to know their intentions, I think you have no business charging bad faith, and I find it somewhat tedious.

As others have mentioned, I think it would be much more productive, not to mention less unpleasant, for the WG to focus on the technical merits of the proposal.

—John

[1] https://en.wikipedia.org/wiki/Polytetrafluoroethylene


On May 15, 2020, at 8:53 AM, Zafar Ali (zali) <zali=[e-mail]<mailto:zali=[e-mail]>> wrote:


Hi John,

You’ll recall what the 6man chairs said in Montreal and Singapore regarding CRH:

During Spring session [1]:  
“[Bob Hinden]  As 6man co-chair, would like to understand whether SPRING is interested in this work.”

Bob reiterated the same message during Singapore IETF [https://mailarchive.ietf.org/arch/msg/ipv6/aWkqPfpvDRyjrW8snR8TCohxcBg/]
“Regarding the Spring related drafts … <snip> We did not see very much value in also discussing them in 6man.   Once items have been adopted in Spring, we think it is appropriate to adopt the IPv6 relevant parts, but that’s not yet the case now.”

Nothing has changed w.r.t. the competing solution review in Spring since Singapore.

Instead of following the chair’s direction, in Feb 2020 the authors of CRH just simply removed normative reference to the SRm6 to get 6man adopt CRH ahead of SPRING compression discussion..

To achieve the said goal, the authors of CRH draft first positioned it as a replacement of RH0.
Now RH0 has been removed from CRH draft.
There is no longer any architecture and use-case to justify adoption call for CRH.

It is clear to all that the current draft and adoption request is an attempt to circumvent the standard practice.

Ref:
[1] https://datatracker.ietf.org/meeting/105/materials/minutes-105-spring-00<https://urldefense.com/v3/__https:/datatracker.ietf.org/meeting/105/materials/minutes-105-spring-00__;!!NEt6yMaO-gk!QbAHSQ3t9Po0n90FQqYbHv8VOpFpwcb739Wzojg7KC2emCeE6TroAjlIlCFOvg$>
Video: Under: Ron’s session on IPv6 Support for Segment Routing: SRv6+       (10:44)

Thanks

Regards … Zafar

From: ipv6 <[e-mail]<mailto:[e-mail]>> on behalf of John Scudder <jgs=[e-mail]<mailto:jgs=[e-mail]>>
Date: Wednesday, May 13, 2020 at 4:02 PM
To: "[e-mail]<mailto:[e-mail]>" <[e-mail]<mailto:[e-mail]>>
Cc: "[e-mail]<mailto:[e-mail]>" <[e-mail]<mailto:[e-mail]>>
Subject: Adoption call criteria for CRH? [was: Re: CRH and RH0]

I’m a little confused about this conversation and I’d like to ask the chairs for clarification. My actual questions are at the end of this long(ish) message, and can be summarized as (1) does 6man require consent from SPRING before defining routing headers, and (2) what criteria are the chairs using to decide when an adoption call is OK?

It seems to me there are at least two, only vaguely related, conversations going on. One of them is a debate about the assertion that 6man can’t even consider taking up CRH unless SPRING approves it. The other is a more free-wheeling line of questioning about “what is CRH for anyway”?

I presume both of these relate to Ron’s request for an adoption call. Here’s what the minutes from the interim have:

Bob: Thank you Ron. I think it's too early for adoption call.

Ron: What is needed to get to adoption call.

Bob: I can't answer right now.

Ron: Can I ask on list?

Bob: OK.

Ole: Related to what's going on in spring.

Too bad we have no audio recording, but that’s not too far from my recollection. Anyway, I don’t think I’ve seen this answered on list yet, so I’m asking again.

Regarding the SPRING-related process stuff:

I have quite a bit of history with how SPRING was chartered; I was one of the original co-chairs and helped write the charter, god help me. I can tell you for certain there was no intent that SPRING should have exclusive ownership of source routing in the IETF, the name isn’t a power-grab, it’s a clever backronym, as we do in the IETF. If one entity in the IETF were to take charge of all source routing, that sounds more like a new area than a WG. But don’t take my word for it, go read the various iterations of the charter. As anyone who’s looked at the Segment Routing document set can tell, Segment Routing is one, very specific, way of doing source routing. As Ketan and others have pointed out, it’s a pile of architecture plus the bits and pieces to instantiate that architecture. That is fine, but the idea that merely because a technology might be used to instantiate part of that architecture, it’s owned by SPRING, is overreach. Just because a sandwich is a filling between two pieces of starch, doesn’t mean every filling between two pieces of starch is a sandwich. [1]

But at any rate, the question for the chairs is: do you think 6man needs SPRING’s permission in order to consider adopting CRH? Does 6man need permission from SPRING for all routing headers, or just some, and if it’s just some, what characterizes them?

Regarding the more general “what is CRH for anyway” stuff:

This seems to me to be exactly the kind of discussion one would normally have in the context of an adoption call. Why is it not being had in that context? To rewind back to the interim, if it’s still “too early for adoption call”, what has to happen for it not to be too early?

Thanks,

—John

[1] https://cuberule.com<https://urldefense.com/v3/__https:/cuberule.com__;!!NEt6yMaO-gk!QbAHSQ3t9Po0n90FQqYbHv8VOpFpwcb739Wzojg7KC2emCeE6TroAjkf2rsQjg$>
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