Re: [B.A.T.M.A.N.] batman goes looping...

Marek Lindner
2009-08-07T15:58:04Z

On Friday 07 August 2009 23:13:46 Yang Su wrote:
> - Some updates: I did more thorough testing. It turns out that this patch
> does really solve the problem. This method seems not able to completely
> eliminate all possible forms of looping which happen in the test cases.
> This result in an special pattern: the rerouting is fast (~15 seconds),
> then (after 3~ 5 seconds) the network enters the looping state and it
> normally takes long time to recover. Last time when I did tests, I stop
> the tests right after I observed the successful rerouting. I didn't look
> into the cause of this problem yet. Any inputs are welcome.

Can you provide logs from the nodes involved ? You also can send them off-list
to avoid sending too big attachments.

> - In the following example (also appended in the attachment :) ), if I
> understand the current echo cancellation implementation correctly, batman
> will enter permanent looping between A and B. In this example, A send to F,
> all the links are perfect and have the same delay. Only exception is link
> A-E. It is an asymmetric link.

Why do you think it would loop permanently and why do you think it is the
fault of the echo cancellation ?
Actually, this example should[tm] be pretty easy. Every time the OGM from E or
F arrive at A via the asymetric link A will apply a severe asymetric link
penalty. All nodes will route via the longer path. Did you try to run this
scenario in your testbed ?

Regards,
Marek