[Olsr-users] Problem with establishing robust relaying in OLSRD

[Markus Kittenberger]

are u sure, your wireless interfaces are working (in adhoc mode)?

Markus

On Mon, Oct 24, 2011 at 12:41 PM, Denia Bouhired <(spam-protected)>wrote:

> Hello all,
>
> Basically we're trying to run olsrd in embedded devices to create
> dynamic mesh networks. We have however been facing problems with olsrd
> that we are finding difficult to understand, let alone fix.
>
> In a simple 3 node setting with nodes A B C, we tried to cause some
> relaying to happen from A to C through B.
>
> A<--->B<--->C
> A<------------>C
>
> We have tried to do this both physically by moving nodes A and C out of
> sight of each other and also by introducing a link multiplyer in
> olsrd.conf between A and C. We tried both etx_ff and etx_fpm for this,
> with little improvement from both. Find attached the olsrd.conf file, we
> are using olsrd 0.6.3.
>
> In the case where we tried to break the link physically between A and C,
> by, say, having A and B fixed and C moving away from A but within LOS to
> C, such that:
>
> A<--->B<--->C
> A<      x       >C
>
> What happens is that the link between A and B starts to degrade even
> though the two of them haven't moved and only C has. If C comes back to
> it's original position than the link between A and B is re-established
> again.
>
>
> In another instance, of what we think is the same problem, we manage to
> establish a 2-hop link between A and C by forcing a link multiplyer
> between A and C so for instance
>
> t1: A<--------------ETX=4------------->C  #Only two nodes in the
> network, only one route exists
> t2: A<---ETX=1--->B<---ETX=1--->C  #Node B inserted, olsrd chooses lower
> cost route through B, ETX=2
>
> The switch between routes was seemless as soon as node B is up in the
> network. This result has been repeatable for any number of power off and
> reboots of node B, the routing table can switch between direct and 2-hop
> links without any problem. The problem has manifested itself when, for
> instance, node C is moved away, then, not only the links from A to B and
> B to C are lost (normal) but alarmingly the link between A and C also
> disappears from the topology and then it is impossible to re-establish
> communication between A and C unless olsrd is restarted. **Even though
> their state hasn't changed.**
>
> As you can see  from the config file, we have enabled the fish-eye
> algorithm as we thought it might be a solution, but it hasn't made any
> difference as far as we can tell.
>
> This same problem has happend to us in various settings, but not
> consistently, so it has not been repeatable. I must also say that most
> times this had happened we had been trying to establish a VoIP link
> between A and C with B relaying the conversation.
>
> We are at loss as to what causes this problem and how to fix it, I hope
> my explanation has been detailed enough and that you'll be able to give
> me some suggestions.
>
> Cheers
> Denia
>
>
>
>
>
> --
> Olsr-users mailing list
> (spam-protected)
> https://lists.olsr.org/mailman/listinfo/olsr-users
>
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