[Olsr-users] OLSR mesh with loop potential... having problems.

[John Clark]

Thanks all,

I updated my olsrd to the 6.3 version that's on the download page. Compiled ok, and did an install and 'install_libs', which seems to have cured my problem with loading the plugins.

I used the default installed olsrd.conf, and only changed the interfaces list.

My net/mesh has 4 nodes, and looks like a 'wheel', where the nodes have direct connection to a 'central node', for 3 direct connections,  and there are 2 other connections that connect the 3 other 'outer' nodes.

When I have all the network connections made, the route tables seem to 'work'...

From the point of view of one of the outher nodes, call it Outer-1, when all is connected, I 'see' the Central-Node in the route table as would be expected.
And networks on the Central-Node, that are not directly connected to Outer-1, are listed as 2 hops away.

I also see Outer-2, directly connected to Outer-1 in the 'LINKS' section.

When I unplug (simulating nework outage...) the direct connect between Outer-1 and Central-Node, Outer-1 route tables do not update to forward to Central-Node, via Outer-2.

I'll try to give a text diagram...

Outer-1  <--Link 4-----> Outer-2  <----Link 5---> Outer-3
     |                                         |                                      |
    Link 1                           Link 2                              Link 3
     |                                         |                                      |
     |                                         |                                      |
[ Central-node three separate interfaces connect to the 3 outer node units ]

I'm prototyping this configuration as copper ethernet links... however when this put into the field, all these connections will be radios and attendant potential outage issues.

I consider the links 1-3 'primary'... and the links 4-5 to be 'secondary'... 

If someone could 'intuit' what I'm trying to achieve, and either make suggestions on how to do that... or olsrd is not the right routing tool to use for dynamic rerouting like this,
I'd appreciate it...

As a note, in the past, upon reflection, my 'meshes' have been either linear chains or trees, and there have bee no internal loops. I'd hate to have to put in some sort of 'sensing code' to sense the connectivity on the various routes, and bring interfaces up, or shut them down, to force the mesh to be a tree or chain...

Thanks,
John Clark.


When everything is connected, the '2 hop' diagnostic indicates that there 2 networks
On Jun 25, 2012, at 10:57 PM, Henning Rogge wrote:

> On 06/26/2012 03:59 AM, John Clark wrote:
>> I've not had to look in to OLSRD and 'mesh' problems for quite some
>> time.
>> 
>> However, I have a new project and am having problems.
>> 
>> The version of OLSRD i'm using was one that is part of the Debian
>> package set, and has the following version number:
>> 
>> 0.5.6-rc7
> 
> 0.5.6-rc7 is a horrible (and horrible old) version of OLSRd. I would
> suggest moving to 0.6.2 or 0.6.3 as soon as possible, otherwise you will
> have to deal with a LOT of bugs which have been fixed for years.
> 
> 
>> I downloaded the most recent src from www.olsr.org, and there seems
>> to be some differences in the config file, and it was not able to
>> find the plugins properly.
> 
> Can you maybe describe what kind of plugins are you using and how your configuration file looks (and whats the output of olsrd is when you start with your old configuration file)?
> 
>> In any case, on looking for others who have had problems with olsr
>> and looping, it seems this has been a problem for some time. I don't
>> know why I didn't see this before when I was using it more, but
>> perhaps most of my 'meshes' were in fact, rather linear or trees and
>> did not contain loops.
>> 
>> Does anyone have some suggestions about dealing with mesh
>> configurations that have potential loops?
> 
> I would suggest you post your configuration file and we have a look over it.
> 
> Henning Rogge
> 
> -- 
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