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Re: [manet] Some comments on draft-funkfeuer-manet-olsrv2-etx-01

Henning Rogge <henning.rogge@fkie.fraunhofer.de> Thu, 19 May 2011 06:17 UTC

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From: Henning Rogge <henning.rogge@fkie.fraunhofer.de>
To: Georg Wittenburg <georg.wittenburg@inria.fr>
Date: Thu, 19 May 2011 08:16:03 +0200
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Cc: manet@ietf.org, David Young <dyoung@pobox.com>
Subject: Re: [manet] Some comments on draft-funkfeuer-manet-olsrv2-etx-01
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On Wed May 18 2011 22:16:06 Georg Wittenburg wrote:
> > What if no OLSR packets are that large ? Do we add padding to get at
> > least one or multiple large packets each second ?
> 
> Sounds like an acceptable trade-off. 
We could use some kind of dummy message (maybe with TTL 0 so it will be 
automatically dropped) for the padding I think.

> Another option would be to include
> data packets in the link loss estimation. Was there any particular reason
> why you decided against including them?
Data traffic is send as unicast, so it includes retransmissions and a different 
modulation in WLAN. Its not intuitively clear how to combine this with 
broadcast measurements.
 
> > > How can packet sizes of lost packets be measured?
> > 
> > Maybe with a second packet sequence number that is only increased for
> > large packets ?
> 
> I don't see the problem here. Both sender and receiver can increment their
> respective packet counters based on the packets (above a certain size, or
> matching other conditions) which they see and ETX should just work as
> expected. Am I overlooking something?
The receiver on a link must estimate the number of lost packets. Our draft 
does this by looking at the packet sequence number to detect missing packets.

If you only want to count packets of a certain size this does not work.
 
Henning Rogge
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