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

[Henning Rogge <[e-mail]>]

On Wed May 18 2011 22:35:39 David Young wrote:
> Let us cross our fingers and hope that each OS provides a uniform API.
And that all drivers use the API... ;)

> > If you rely on the rate control, you need to send unicast probing packets
> > to all of your neighbors regularly if you have no traffic in this
> > direction.
> 
> It seems to me, too, that that is a problem with using a rate
> adaptation.  One hopes that there are probe packets or else that the
> inherent background unicast traffic keeps the rate adaptation fresh.  I
> think that having to induce some unicast traffic may be a reasonable
> trade-off for being able to derive a link metric from the rate
> adaptation.
It would be necessary to do so if no unicast traffic is on a link.
 
> FWIW, I have lingering doubts whether or not a link metric can be
> updated or link metrics propagated nearly as quickly as the channel
> makes a substantial change of state.  From N hops away, a single metric
> for a link may not be nearly as useful in a routing decision as the
> historical range or distribution of metrics on a link.  People have
> experimented with "opportunistic" routing/forwarding, I think this is
> why.
I think this hysteresis/history of a link could be directly included into 
metric calculation of a link. The Draft is doing it in a very limited way by 
averaging over a certain period of time.

Henning Rogge
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