Re: [manet] New Version Notification for draft-ietf-manet-timetlv-03

Comments inline.

On Nov 20, 2007 3:23 PM, Dearlove, Christopher (UK)
<Chris.Dearlove@baesystems.com> wrote:
>
> I'm in agreement that this is neither intended nor
> desirable. Actually I don't think it's ever desirable,
> but especially not in timetlv.

I am not concerned about the timetlv format. I am concerned about the
two TLVs specified/allocated in the TimeTLV document. That is VALIDITY
and INTERVAL.

> Why never desirable? First it isn't usually necessary.
> If C = 1 ms you can have times up to 1.5 months at
> millisecond resolution. If C = 1 second you can have
> times up to over a century, at second resolution.
> (Other figures are of course possible.)
>
> Second the point of timetlv is passing an unambiguous
> time, often in circumstances where communications has
> not yet been established. If you had to negotiate C for
> routing (which is after all why we are here) you'd have
> to do that before any other form of topology formation
> etc. that used C. This would be really bad. So for our
> main use cases, negotiating C really doesn't work.

This fact seems to motivate that C been defined/specified somewhere
for any timetlv instance. Otherwise, misunderstandings could cause
major problems.

I believe this may be one of the reasons that OSPF carries timing
information in its messages.

Ian

> Yes, I can conceive of a protocol that want to negotiate
> C (that doesn't however mean I think it's likely - I
> think it's very unlikely given my first point). If so
> that protocol can define such a process. It's way outside
> what timetlv should include, especially given that it's
> an obscure case. (And as we have no prior art, defining a
> good mechanism would be tricky.)
>
> Realised there's one more point. If you want to define C
> in the same message as one of the timetlv TLVs, that
> suggests you may not be using the right format in the
> first place.
>
>
> -----Original Message-----
> From: Ian Chakeres [mailto:ian.chakeres@gmail.com]
> Sent: 18 November 2007 09:56
> To: manet@ietf.org
> Cc: T.Clausen@computer.org; Dearlove, Christopher (UK)
> Subject: Re: [manet] New Version Notification for
> draft-ietf-manet-timetlv-03
>
>
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>
> I think it would be useful for TimeTLV to specify a method for
> carrying 'C'. I understand that normally nodes (or implementations)
> might be configured with 'C' for each TimeTLV type. For cases where C
> is either unknown or required, I think we should specify a format for
> carrying it. I see carrying C as most important when C
> misunderstandings could cause routing to fail.
>
> I believe there are several different options for encoding this
> information. What do you think would be the best way?
>
> Ian
>
> On Nov 15, 2007 9:48 PM, IETF I-D Submission Tool
> <idsubmission@ietf.org> wrote:
> >
> > A new version of I-D, draft-ietf-manet-timetlv-03.txt has been
> successfuly submitted by Thomas Clausen and posted to the IETF
> repository.
> >
> > Filename:        draft-ietf-manet-timetlv
> > Revision:        03
> > Title:           Representing multi-value time in MANETs
> > Creation_date:   2007-11-15
> > WG ID:           manet
> > Number_of_pages: 18
> >
> > Abstract:
> > This document describes a general and flexible TLV (type-length-value
> > structure) for representing time using the generalized MANET packet/
> > message format.  It defines two message and two address block TLVs
> > for representing validity and interval times for MANET routing
> > protocols.
> >
> >
> >
> > The IETF Secretariat.
> >
> >
> >
> >
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> > manet@ietf.org
> > https://www1.ietf.org/mailman/listinfo/manet
> >
>
>
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