On Don, 2007-10-04 at 21:31 +0300, Acinonyx wrote:
> On Thursday 04 October 2007 13:14:33 Hannes Gredler wrote:
> >
> > since you seem to dislike the flat metric scheme and i still think
> > is useful, can we bargain such that we can hide the metric stuff
> > under #ifdef OLSR_FLAT_METRICS ... then you can enable that
> > for freifunk ...
> >
> > /hannes
> 
> Hello from Athens,
> 
> We use olsrd with quagga plugin, inside BGP confederations. Metric is 
> essential to us because best nexthop to neighboring ASes is calculated by 
> this IGP metric. If this information is missing, nexthop will be determined 
> practically at random.

I didn't check but Quagga could (and should) always get the correct
metric
information since OLSRD has it (since it must decide himself on the best
route
and it shows it e.g. in the httpinfo plugin too).

The (so-called) flat metrics feature is actually more a performance hack
since
it avoids lots of system calls just to update the metric value in the
kernels
routing table for routes to hosts where it doesn't buy anything.

And even worse there is no "update route" ioctl(2) or similar call -
that must
be implemented via "delete route" and "add route" and increases thus
also the 
work in the kernel for practically next to no gain.

Of course there are situations where you need the correct information in
the
kernel routing table (if only because some other application uses it).
Therefore I want a run-time option and people can decide what they want.

	Bernd
-- 
Firmix Software GmbH                   http://www.firmix.at/
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