Re: [Roll] impacts of rfc2460bis on draft-ietf-roll-useofrplinfo

Brian E Carpenter <brian.e.carpenter@gmail.com> Tue, 19 July 2016 11:14 UTC

To: Michael Richardson <mcr+ietf@sandelman.ca>, roll@ietf.org, 6man@ietf.org
References: <24554.1468868593@obiwan.sandelman.ca> <799ab640-bed0-22a6-a9df-97f78c3f0bf8@gmail.com> <30725.1468924267@obiwan.sandelman.ca>
From: Brian E Carpenter <brian.e.carpenter@gmail.com>
Organization: University of Auckland
Message-ID: <c342e18c-d2d8-8b97-12ba-f67c25413d4f@gmail.com>
Date: Tue, 19 Jul 2016 23:05:44 +1200
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Subject: Re: [Roll] impacts of rfc2460bis on draft-ietf-roll-useofrplinfo
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Reply-To: Routing Over Low power and Lossy networks <roll@ietf.org>

On 19/07/2016 22:31, Michael Richardson wrote:
> 
> Brian E Carpenter <brian.e.carpenter@gmail.com> wrote:
>     >>
>     >> The ROLL document draft-ietf-roll-useofrplinfo documents RFC6553 (a
>     >> Hop-by-Hop critical option) and 6554 (a form of Source Routing Header, RH3).
>     >> There is work on 6lo to allocate additional 6lowpan IPHC codes such that
>     >> the work in ROLL:
>     >> https://datatracker.ietf.org/doc/draft-ietf-roll-routing-dispatch/ can
>     >> know what kinds of things we need to compress.
>     >>
>     >> A number of things are constrained by the need to always remove the
>     >> RFC6553 Hop-by-Hop option RPI option which had been marked critical:
>     >> i.e. drop packet if you don't understand it.
>     >>
>     >> As a result of the change in RFC2460bis, which says that intermediate hosts
>     >> will in general not examine hop-by-hop options, but should just ignore
>     >> them, we can make certain simplications to the useofrplinfo document.
>     >> (rfc2460bis, section 4, page 8, "NOTE: While...)
> 
>     > You can already do that, because RFC7045 section 2.2 updates RFC2460:
>     > " The IPv6 Hop-by-Hop Options header SHOULD be processed by
>     > intermediate forwarding nodes as described in [RFC2460]."
>     > which of course means that forwarding nodes MAY ignore HbH.
> 
> It's not what *I* want to do, it's what *I* can expect *others* to do.
> So 7045 doesn't help me.

Well, it legitimizes a router simply ignoring a HbH header. Isn't that useful?

> 
>     > 00 - skip over this option and continue processing the header.
> 
> A type=10 option was allocated by RFC6553
> 
> I think it was a mistake. 

Agreed.
    Brian

> We have discussed changing it as we add
> compression for 6553, 6554 and IPIP (which would be a flag day anyway).
> This was considered undesireable, because there was a desire not to leak
> our headers; that the internet would drop our packets if we screwed up.
> 
> But, it turns out that the internet won't drop out packets, so we might
> as well optimize the situation so that if we don't need to remove our
> Hob-by-Hop header, then we don't need extra IPIP headers.
> 
> --
> Michael Richardson <mcr+IETF@sandelman.ca>, Sandelman Software Works
>  -= IPv6 IoT consulting =-
> 
> 
>

Re: [Roll] impacts of rfc2460bis on draft-ietf-ro… Brian E Carpenter
Re: [Roll] impacts of rfc2460bis on draft-ietf-ro… Michael Richardson
Re: [Roll] impacts of rfc2460bis on draft-ietf-ro… Michael Richardson
Re: [Roll] impacts of rfc2460bis on draft-ietf-ro… Pascal Thubert (pthubert)
Re: [Roll] impacts of rfc2460bis on draft-ietf-ro… Pascal Thubert (pthubert)
Re: [Roll] impacts of rfc2460bis on draft-ietf-ro… Brian E Carpenter
Re: [Roll] impacts of rfc2460bis on draft-ietf-ro… Michael Richardson
Re: [Roll] impacts of rfc2460bis on draft-ietf-ro… Brian E Carpenter
[Roll] impacts of rfc2460bis on draft-ietf-roll-u… Michael Richardson
Re: [Roll] impacts of rfc2460bis on draft-ietf-ro… Tim Chown