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Re: [manet] Default metric in OLSRv2



I also agree with Thomas' mail that it would be very helpful to have a draft that describes the ETX metric, before continuing the discussion whether or not to include it in the OLSRv2 draft. Henning and Aaron seem to be the ideal candidates for writing such a draft, since they have running code (of OLSRv1) that includes ETX metrics, and since they have the operational experience of a big OLSR network.

Henning, Aaron, if you guys agree to write such a draft, I am also offering to help out.

Ulrich


On Wed, Oct 14, 2009 at 12:33 PM, Dearlove, Christopher (UK) <Chris.Dearlove at baesystems.com> wrote:
I agree with almost all of Thomas's message (I might have one
small nitpick, but it's not important right now) and that
definitely includes the conclusion, that an ETX draft would
be valuable - and actually not just in an OLSRv2 context.

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-----Original Message-----
From: Thomas Heide Clausen [mailto:thomas at thomasclausen.org]
Sent: 14 October 2009 11:25
To: Dearlove, Christopher (UK)
Cc: Henning Rogge; manet at ietf.org
Subject: Re: [manet] Default metric in OLSRv2


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All,

Can I make a couple of rush observations and a suggestion here,
without taking side in this discussion just yet?

Observations:

       o       We agree that additive metrics should be in OLSRv2.

                       =>      They will be, we've got consensus on
that,
                               the metrics I-D contains that and it
will be
                               (I believe that I can safely engage all
the authors)
                               folded into the OLSRv2 specification as
the WG
                               has decided.

       o       ETX is a valuable example of a metric. There are
existence
               proofs (plural) hereof from operational networks. It's
hard
               to argue against that. It's also hard to argue that ETX
is the
               be-all-end-all metric (but I think that nobody has
suggested
               that either).

       o       Regardless of if ETX is to be included in the OLSRv2
spec
               or published as an independent spec (and I see and
recognize
               arguments for and against both of these options),
there's no
               current (IETF) specification of ETX. Consequently:

                       =>      It's difficult for the WG to pronounce
itself on the
                               issue

                       =>      There's no ETX-text to propose folding
in to any
                               specification, or to advance as a
supplementary
                               document (i.e. for the WG to adopt and
to advance
                               for publication).

Suggestion:

       o       Someone with experience in ETX and OLSR(v2) produce
               an individual I-D (short is good, shorter is better),
and post
               to manet at ietf.org for further discussion.


Informally, as I know that Henning and Aaron have significant
operational experience with ETX in OLSR(v2) networks, I'd think it
interesting and a good idea if you were to produce such a document.
I'd be happy [as OLSRv2 co-author] to help out, as will Emmanuel (he
just confirmed this, as he's next to me) -- and I am sure that so will
others.

I am sure that once a document exists, it will be a lot easier to
understand what it is that we're discussing, what the right path for
the content is etc.

Thoughts?

Thomas


On Oct 14, 2009, at 11:48 AM, Dearlove, Christopher (UK) wrote:

>> I don't think this will work well for OLSRv2. Most people using
>> OLSRv2
> for
>> research (instead of doing research on OLSRv2) will continue to use
> the "basic
>> RFC implementation" of OLSR... if the basic RFC does only contain
> hopcount
>
> That is not the proposal. See what's written in the metrics draft.
> (I agree what you indicate would not be acceptable. But that's why
> that isn't it.)
>
> The proposal is that the default is an additive metric of unspecified
> "real world" meaning. But it's still a metric, and not just hopcount.
> It's just not a specific ETC/delay/whatever metric. At least not
> specified as such. In a given deployment if you agree in advance that
> this is ETX, fine. But if you definitely want ETX then get an
> allocation
> of one of the reserved metric code points specifically for that
> purpose
> and use that.
>
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