Hi Brian,
On Thu, 18 Feb 2010 16:34:05 +1300
Brian E Carpenter <brian.e.carpen...@gmail.com> wrote:
> Hi,
>
> This may seem a bit unexpected, but after working on draft-carpenter-flow-ecmp
> (just updated) and working with my student Qinwen Hu on some aspects
> of the flow label, it seemed like time for another look at the flow
> label standard, and Sheng Jiang was having similar thoughts.
>
> We'd like to discuss this in Anaheim if possible.
>
I've had a read through this draft and support what it is
proposing.
In regarding the following processing rules:
o Considering packets outbound from the Flow Label Domain, if MSB =
0, a boundary router MUST NOT change the flow label. If MSB = 1,
it MUST set all 20 bits of the flow label to zero, so that the
locally defined behaviour is not exported from the domain.
o Considering packets inbound to the Flow Label Domain, if MSB = 0,
a boundary router MUST NOT change the flow label. If an inbound
packet has MSB = 1, it has originated from a source not following
the current specification. This is considered to be an extremely
unlikely case, and the boundary router MUST set all 20 bits of the
flow label to zero, as the choice least likely to cause unwanted
behaviour. (Note that this means the rules for inbound and
outbound packets at the boundary router are identical.)
one thought I had would be that there could be a use case where e.g.
when a packet leaves a flow domain and has it's MSB=1, and enters
another flow domain e.g. crossing the boundary between enterprise
network and an ISP, the flow label could be changed to a MSB=1 value
of local significance to the second flow domain. This would be somewhat
similar to how ISPs can provide specific BGP community values for it's
customers to set to influence routing within the ISP's AS. If there is
no specified MSB=1 value for the second flow domain, then the flow label
must be set to all zeros.
Regards,
Mark.
> Brian
>
> -------- Original Message --------
> Subject: I-D Action:draft-carpenter-6man-flow-update-00.txt
> Date: Wed, 17 Feb 2010 18:15:02 -0800 (PST)
> From: internet-dra...@ietf.org
> Reply-To: internet-dra...@ietf.org
> To: i-d-annou...@ietf.org
>
> A New Internet-Draft is available from the on-line Internet-Drafts
> directories.
>
> Title : Update to the IPv6 flow label specification
> Author(s) : B. Carpenter, S. Jiang
> Filename : draft-carpenter-6man-flow-update-00.txt
> Pages : 9
> Date : 2010-02-17
>
> Various uses proposed for the IPv6 flow label are incompatible with
> its existing specification. This document describes changes to the
> specification that permit additional use cases as well as allowing
> continued use of the previous specification.
>
> A URL for this Internet-Draft is:
> http://www.ietf.org/internet-drafts/draft-carpenter-6man-flow-update-00.txt
>
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