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

Henning,

On Fri, Apr 20, 2018 at 7:05 AM, Henning Rogge <hrogge@gmail.com> 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?
>

What we did at Cisco was to add to the route cost, based on how much RLQ
had dropped. A document on the route cost calculations (for OSPF) is at
https://www.cisco.com/c/en/us/td/docs/ios/12_4t/ip_mobility/configuration/guide/ip_manet.html
Look for Section "OSPF Cost Calculation for VMI Interfaces". You'll see we
used a hard-coded '65535' in the calcuations, IIRC, (it's been a few
years), that's the maximum OSPF route cost.

My guess is that this specific equation won't fit your needs, but it might
serve as a template for you.

Regards,
Stan

> 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.
>
> 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
> >>
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