[Olsr-dev] OLSRd V2 - ethernet-Links / measure speed

[Henning Rogge]

On Wed, May 28, 2014 at 11:49 AM, Bastian Bittorf
<(spam-protected)> wrote:
> i was thinking again about this prob and my conclusion is this:
> there is no good way to be sure that we have an ethernet-interface,
> because even this can be in reality a wifi link/bridge:
>
> router/olsrd2:eth --- eth:blackbox:wifi ~~~ wifi:blackbox:eth ---eth:router/olsrd2
>
> so we must probe the linkspeed in a similar way like we query
> a normal wifi link. there are only some ways to guess, that it is
> ethernet, but in the end...we have to test.

I don't think measuring every point-2-point connection (every few
seconds) on every non-wifi connection is a good idea.

The eth_listener plugin might be a hack that we have to remove again,
but just spamming measurements is not really that much better.

> so, if interface is _not_ wifi:
> can we "just" send a ping with small and large packets and compare the RTT?

This only works well if you do it often enough to compensate for the
noise of the measurement, including time differences by buffers and
userspace scheduling.

It should be easy to supply (semi-)static information from an external
tool to olsrd2, but I am not convinced that having a built-in iperf in
every mesh routing protocol is the best way to do it.

Henning Rogge