Re: [spring] SRH scratch space (was Re: Question about SRv6 Insert function)

Robert Raszuk <robert@raszuk.net> Wed, 11 December 2019 08:37 UTC

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From: Robert Raszuk <robert@raszuk.net>
Date: Wed, 11 Dec 2019 09:37:10 +0100
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To: Brian E Carpenter <brian.e.carpenter@gmail.com>
Cc: Erik Kline <ek.ietf@gmail.com>, Suresh Krishnan <suresh.krishnan@gmail.com>, Ron Bonica <rbonica=40juniper.net@dmarc.ietf.org>, "spring@ietf.org" <spring@ietf.org>, "6man@ietf.org" <6man@ietf.org>, draft-voyer-6man-extension-header-insertion <draft-voyer-6man-extension-header-insertion@ietf.org>, Fernando Gont <fernando@gont.com.ar>, draft-ietf-spring-srv6-network-programming <draft-ietf-spring-srv6-network-programming@ietf.org>
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Subject: Re: [spring] SRH scratch space (was Re: Question about SRv6 Insert function)
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Hi Brian,

> Each SR node (Segment Endpoint) is effectively applying new IPv6 encap so
> is already doing an insertion of new SRH
>
> That isn't "insertion" in the sense of draft-voyer.


Correct. But we are not discussing draft-voyer here.

I think recent mail threads prove that it is much better to discuss one
topic at a time rather then mix three different and pretty orthogonal
"issues" interchangeably.


>  . It's prepending an extra layer of encapsulation, which is indeed just
> fine and I don't think anyone here is objecting to it. The spring draft
> currently uses (IMHO) imprecise language, even in its pseudo-code, but if
> all it's doing is describing successive layers of encapsulation that's fine
> too. Wasted bytes perhaps, but that isn't an IETF problem.


Great that we agree.


> Whether prepending new headers, each with their own SRH, is the best way
> of doing service-based traffic engineering is another question. Having just
> reviewed draft-ietf-bess-nsh-bgp-control-plane for Gen-ART, I do believe
> there's more than one possible approach.
>

100% agreed. In fact as you may have seen I have another non data plane,
but control plane proposal posted:
https://tools.ietf.org/html/draft-raszuk-teas-ip-te-np-00

Kind regards,
R.