[Olsr-dev] Seeking comments: OLSR+ETX v/s DSR+ETX

Henning Rogge (spam-protected)
Wed Dec 19 17:22:11 CET 2007

On Dec 19, 2007 3:58 PM, elektra <(spam-protected)> wrote:
> Before we decided to choose ETX as metric for olsrd we were experimenting with
> measuring round trip times. Axel Neumann tried to implement this while we
> were still using mobilemesh, but the measurement results seemed to be quite
> arbitrary. But I assume this was a problem of our implementation, because any
> implementation of ping does a much better job than what we had achieved.
> And btw. I don't see any irrational 'voodoo' in LQ/NLQ/ETX - at night I can do
> downloads in our mesh via 18 hops with approx. 12 kByte/sec... Some people
> claimed that a mesh only works up to three hops. So the 'voodoo' seems to
> help a lot ;-)

This might be interesting for anyone interested in ETX...
[ETX metric 2003] Couto, Douglas S. J. D. ; Aguayo, Daniel ; Bicket, John ;
  Morris, Robert: A High-Throughput Path Metric for Multi-Hop Wireless Routing.
  URL http://pdos.csail.mit.edu/papers/grid:mobicom03/paper.pdf, September 2003

> So I still think it would be a valuable idea to measure RTT for different
> packet sizes. And the payload of these packages should transport something
> useful... For example the results of the last RTT-measurement could be
> included.
How do you want to do this for unicast packages ? I can see it working
for broadcast
(no retransmission on Layer 2), but broadcast and unicast timing are
not the same.

Henning Rogge

"Wo kämen wir hin, wenn alle sagten, wo kämem wir hin, und niemand
ginge, um einmal zu schauen, wohin man käme, wenn man ginge." (Kurt

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