Re: Adoption Call for "The IPv6 Compact Routing Header (CRH)"

["Henderickx, Wim (Nokia - BE/Antwerp)" <[e-mail]>]

Gyan,

RFC 8663 is defining a framework to encap. SID(s) if you will in ipv4 or ipv6 and there are various encaps defined. UDP based, mainly for ipv4 and native v6 RFC 4023 or a GRE flavor.. If you look at the native v6 flavor of RFC4023 which is not using GRE, etc. What you get is a v6 header where we add SID(s) in the next header before the real payload. Think of them as instructions which define a behavior.

If you compare CRH, it is similar wrt the bevior. You have a v6 header where in an extensions header you encode some SID, which are instructions.

Now look at the intrinsic behavior that CRH has wrt steering. For the node that process the SID, you do a lookup and define the next behavior, which is essentially getting a v6 address for the next hop in the chain. You can do the same thing with RFC8663.

From: Gyan Mishra <[e-mail]>
Date: Wednesday, 27 May 2020 at 06:16
To: "Henderickx, Wim (Nokia - BE/Antwerp)" <[e-mail]>
Cc: Bob Hinden <[e-mail]>, IPv6 List <[e-mail]>
Subject: Re: Adoption Call for "The IPv6 Compact Routing Header (CRH)"

Hi Wim

You mention SR-MPLS and SR-MPLS over IP as if they are two different flavors of SR.  They are one and the same per RFC 8663.  Am I missing something here?

SR-MPLS reuses the MPLS IPv4 LDPv4 data plane once LDPv4 is removed from the network to provide a stateless SR-MPLS based on 4 byte MPLS shim now containing new SRGB label range.

Are you referring to MPLSoUDP RFC 7510 or MPLS over GRE RFC 4023 and using SR-MPLS reuse of MPLS data plane IPv4 and tunneling via GRE is UDP?

Not sure how that would work or make it similar to CRH.

I am not following how SR-MPLS is similar to CRH.

Please explain?

Gyan

On Tue, May 26, 2020 at 11:33 PM Henderickx, Wim (Nokia - BE/Antwerp) <[e-mail]<mailto:[e-mail]>> wrote:
Gyan, if you look in the details of RFC8663, you can do all of the things you mentioned. You can do loose path which are connected via ipv6 island exactly like CRH is proposing and more. As said here is a misconception that RFC8663 is strictly MPLS and I have to repeat it is not. You can do all the things that are suggested with CRH and more, with the same addressing mechanism, etc that is proposed in CRH. On top you get the natural extensions we are defining for free.
There is no need to reinvent the wheel here.

From: Gyan Mishra <[e-mail]<mailto:[e-mail]>>
Date: Wednesday, 27 May 2020 at 01:41
To: "Henderickx, Wim (Nokia - BE/Antwerp)" <[e-mail]<mailto:[e-mail]>>
Cc: Bob Hinden <[e-mail]<mailto:[e-mail]>>, IPv6 List <[e-mail]<mailto:[e-mail]>>
Subject: Re: Adoption Call for "The IPv6 Compact Routing Header (CRH)"


Wim

SR-MPLS reuses the MPLS data plane.  That is a nice brown field migration option for MPLS customers that want to eliminate ldp state.

Don’t get me wrong SR-MPLS has its place and its for brown field MPLS deployments and SRv6 has its place as well for cases mostly intra domain where you don’t have inter domain traffic steering with very long strict paths which run into SR-TE MSD issues.

For deployments that want to use the IPv6 data plane and have ubiquitous use cases inter or intra domain and not have the extra baggage 🧳 of SRv6 programming SID depth overhead with strict paths or  SR-MPLS - MPLS data plane which also has MSD SID depth issue with long strict paths = CRH shines and is the best solution

Thanks

Gyan

On Tue, May 26, 2020 at 10:27 AM Henderickx, Wim (Nokia - BE/Antwerp) <[e-mail]<mailto:[e-mail]>> wrote:
if you look into the details RFC8663 from a data-plane operation is very similar to CRH. It uses a tag and derives a destination ipv6 address from it.
On top it if you look at the requirements which are discussed on the mailing list, the following is possible with RFC8663

It can steer the packet through a specific path. Implementations exists which do well beyond 8
No new VPN encapsulation is required
No new service chaining needed and various options possible.
Compliant to SPRING
Uses MPLS but it is used here as a lookup tag, not any different than the CRH proposal. In essence if you look at the details you can implement this with a complete v6 infrastructure and use the tag as a steering function. And uses 32 bit.

As such I don’t see why we need another encap to achieve something we already can do and is available in various implementations and is as efficient on the wire (looking at 32 bit, which is what people agree upon).

So I would vote against adoption.

On 16/05/2020, 00:14, "ipv6 on behalf of Bob Hinden" <[e-mail]<mailto:[e-mail]> on behalf of [e-mail]<mailto:[e-mail]>> wrote:

    This message starts a two-week 6MAN call on adopting:

     Title:          The IPv6 Compact Routing Header (CRH)
     Authors:        R. Bonica, Y. Kamite, T. Niwa, A. Alston, L. Jalil
     File Name:      draft-bonica-6man-comp-rtg-hdr-21
     Document date:  2020-05-14

     https://tools.ietf.org/html/draft-bonica-6man-comp-rtg-hdr

    as a working group item. Substantive comments regarding adopting this document should be directed to the mailing list.  Editorial suggestions can be sent to the authors.

    Please note that this is an adoption call, it is not a w.g. last call for advancement, adoption means that it will become a w.g. draft.  As the working group document, the w.g. will decide how the document should change going forward.

    This adoption call will end on 29 May 2020.

    The chairs note there has been a lot of discussions on the list about this draft.   After discussing with our area directors, we think it is appropriate to start a working group adoption call.  The authors have been active in resolving issues raised on the list.

    Could those who are willing to work on this document, either as contributors, authors or reviewers please notify the list.   That gives us an indication of the energy level in the working group
    to work on this.

    Regards,
    Bob and Ole



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Gyan Mishra

Network Solutions Architect

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Gyan Mishra

Network Solutions Architect

M 301 502-1347
13101 Columbia Pike
Silver Spring, MD