Hi Ron,
sorry I'm slightly confused now... see below.
On 09.09.2015 22:49, Ronald Bonica wrote:
Suresh,
You are absolutely right. We have two possible solutions, an HBH Option and a
Destination Option. Both solutions severely limit CONEX deployability.
Since my comment is more about draft-ietf-conex-destopt than it is about
draft-ietf-conex-tcp-modifications, I think that we can let
draft-ietf-conex-tcp-modifications go forward, as is.
Before draft-ietf-conex-tcp-modifications comes up for last call, we might want
to augment Section 5, explaining why both solutions limit severely limit CONEX
deployability. Since all of the CONEX documents are EXPERIMENTAL, that caveat
shouldn't be an impediment to publication.
Just as a side note last call for both docs is already over, but that's no
problem.
I'm not sure where and in which document you want to change something now. >From
my point of view draft-ietf-conex-tcp-modifications does not have to give a
justification because it's simply using what's defined in
draft-ietf-conex-destopt. And draft-ietf-conex-destopt does give some reasoning
why this choice was taken.
Btw. draft-ietf-conex-destopt is basiaclly already finished for quite some time,
we just waited to submit it until the other docs are ready in case we detect
something that would require a change in draft-ietf-conex-destopt.
Please tell me again what you'd propose to change where!
Thanks,
Mirja
We will need to address the problem before the CONEX documents become PROPOSED
STANDARD. But we can cross that bridge when we get to it.
Ron
-----Original Message-----
From: Suresh Krishnan [mailto:[email protected]]
Sent: Tuesday, September 08, 2015 2:47 PM
To: Ronald Bonica <[email protected]>; [email protected]
Cc: [email protected]
Subject: Re: [Gen-art] Gen-ART review of draft-ietf-conex-tcp-modifications
Hi Ron,
Thanks for your review. Please find comments inline.
On 09/08/2015 12:20 PM, Ronald Bonica wrote:
I am the assigned Gen-ART reviewer for this draft. For background on
Gen-ART, please see the FAQ at
<http://wiki.tools.ietf.org/area/gen/trac/wiki/GenArtfaq>
Document:
draft-ietf-conex-tcp-modifications-09
Reviewer: Ron Bonica
Review Date: 2015-09-07
IETF LC End Date: 2015-08-31
IETF Telechat Date: 2015-10-01
Summary: This document will be ready for publication as soon as the
major issue (below) below is addressed.
Major Issues:
This document contains a normative reference to draft-ietf-conex-destopt-
09. The normative reference is appropriate, because this document doesn't
work at all unless the concepts described in draft-ietf-conex-destopt-09
work.
I am concerned about draft-ietf-conex-destopt-09. It uses an IPv6
Destination Option to signal CONEX state to intermediate routers. However,
according to RFC 2460:
"With one exception, extension headers are not examined or processed
by any node along a packet's delivery path, until the packet reaches
the node (or each of the set of nodes, in the case of multicast)
identified in the Destination Address field of the IPv6 header."
The exception to which RFC 2460 refers is the Hop-by-hop Extension
Header. Intermediate routers don't examine Destination Options.
Section 5 of draft-ietf-conex-destopt-09 attempts to address this issue, but
I am not sure that the argument is acceptable.
I think we can discuss this further but in my view there are no good solutions
to this problem. There are two probable alternatives here
Hop-by-hop options: This is arguably the right way to define information that
is inspected on intermediate nodes. But using this implies that there is a huge
performance penalty for conex packets that hit conex unaware routers
(basically being punted into the slow path in the best case, being dropped at
worst). RFC7045 section 2.2 talks about this explicitly but this problem has
been known for much longer. This will break requirement R-3.
Destination options: Intended for the destination of the packet, but capable
of being read at *consenting* conex-aware network nodes. Does not affect
nodes that are conex unaware. This is no different than a router that looks at
a TCP port for an enforcing an ACL, right?
Let me know what you think. (Especially, we would be grateful if you think
there is a better solution we ought to be considering that would meet the
requirements)
Regards
Suresh
--
------------------------------------------
Dipl.-Ing. Mirja Kühlewind
Communication Systems Group
Institute TIK, ETH Zürich
Gloriastrasse 35, 8092 Zürich, Switzerland
Room ETZ G93
phone: +41 44 63 26932
email: [email protected]
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