[Olsr-users] Received message to big to be forwarded

[Henning Rogge]

The only other option I see is to set the MTU size for olsrd messages
to 1280-40-8=1232 bytes... which should be guaranteed for all IPv6
capable networks.

Henning

On Fri, Apr 17, 2015 at 2:25 PM, Ferry Huberts <(spam-protected)> wrote:
>
>
> On 17/04/15 14:22, Henning Rogge wrote:
>>
>> On Fri, Apr 17, 2015 at 2:07 PM, Jernej Kos <(spam-protected)> wrote:
>>>
>>> Hello!
>>>
>>> We are seeing a lot of the following messages in our logs:
>>>
>>> Received message to big to be forwarded on digger1226(1296 bytes)!
>>> Received message to big to be forwarded on digger1346(1328 bytes)!
>>>
>>> The message sizes indicate that the OLSR messages that are to be
>>> forwarded are probably larger than the MTU (the OLSR daemon has multiple
>>> interfaces with different MTU sizes). Does this warning indicate some
>>> problems with propagating routing information as messages are dropped
>>> instead of being forwarded?
>>
>>
>> The problem is that olsrd cannot fragment messages (which are flooded
>> through the whole mesh) hop-by-hop... which means a network with
>> different MTU-sizes AND large neighborhoods (which produce huge
>> messages) is a problem.
>>
>
> Yes, you should really setup a lower MTU on all your nodes
>
>> Henning Rogge
>>
>
> --
> Ferry Huberts