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Re: [manet] (DLEP) Relative Link Quality and routing metrics

Rick Taylor <rick@tropicalstormsoftware.com> Fri, 20 April 2018 12:55 UTC

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From: Rick Taylor <rick@tropicalstormsoftware.com>
To: "hrogge@gmail.com" <hrogge@gmail.com>
CC: "manet@ietf.org" <manet@ietf.org>
Thread-Topic: [manet] (DLEP) Relative Link Quality and routing metrics
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Date: Fri, 20 Apr 2018 12:55:34 +0000
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Subject: Re: [manet] (DLEP) Relative Link Quality and routing metrics
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Inline...

On Fri, 2018-04-20 at 13:05 +0200, Henning Rogge wrote:
> Sorry,
> 
> but this does not help...
> 
> lets say I estimate the link cost for a link (based on data-rate) to
> be 1000...
> 
> if the radio reports RLQ=100, I would keep the 1000... but how do I
> modify it for a RLQ of 80... or 50... or 1?
> 
> If I cannot integrate the value into the cost metric, I have no use
> for the value. Unfortunately it is often the ONLY value the radio
> reports.

I would suggest you return to the radio vendor and request they support
more metrics than RLQ in updates.

If they are DLEP compliant, then they MUST support MDR,CDR,Latency per
session, and you could modify the session-wide CDR values by the RLQ in
some non-uniform manner.

Rick

> 
> Henning
> 
> On Fri, Apr 20, 2018 at 1:02 PM, Rick Taylor
> <rick@tropicalstormsoftware.com> wrote:
> > I have always suggested that RLQ should be a measure of how hard
> > the
> > modem is working to maintain the link, i.e. the higher the RLQ, the
> > more stable the link is, and a low RLQ indicates that the link may
> > well
> > radically change metrics, or dissapear soon.
> > 
> > One can imagine a sophisticated modem maintiaining a link in very
> > adverse conditions, reporting a low RLQ, but otherwise good
> > metrics.
> > 
> > Whether RLQ is a good metric to use as a route cost is a more
> > difficult
> > question.  I've always been of the opinion that RLQ and Resources
> > make
> > a good tie-breakers, but CDR and Latency make better 'primary'
> > metrics.
> > 
> > Hope that helps a little?
> > 
> > Rick
> > 
> > On Fri, 2018-04-20 at 10:00 +0200, Henning Rogge wrote:
> > > Hello,
> > > 
> > > I am currently looking for a good way to integrate the RLQ value
> > > of
> > > DLEP into a cost based routing metric, e.g. DAT. But I am not
> > > sure
> > > how
> > > to do this...
> > > 
> > > has anyone here good experience using RLQ and maybe an advise how
> > > "hard" you should penalize a link with a RLQ less than 100?
> > > 
> > > Henning Rogge
> > > 
> > > _______________________________________________
> > > manet mailing list
> > > manet@ietf.org
> > > https://www.ietf.org/mailman/listinfo/manet

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