[Olsr-users] Howto feed routing-table into OLSRd2?

[Henning Rogge]

On Wed, Jun 10, 2015 at 12:03 AM, Bernd Naumann <(spam-protected)> wrote:
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> I have an idea / a question on that topic:
>
> Would it be sane to run olsrd and olsrd2 on one node, but to forbid
> olsrd to change system routes, and only feed these routing information
> to the olsrd2 lan import plugin maybe via telnet dump --> olsrd2 plugin?

Yes, it would not be difficult to write an olsrd2 importer that reads
from txtinfo/jsoninfo. But that is just a small part of the problem.

> What will happen if multiple olsrd2 nodes announcing the same olsr
> subnets as local attached network? Is that a problem or possible?

imported routes are "locally attached networks", which is the same as
HNA in olsrd1. If you have multiple of them, the mesh will route to
the closest "gateway". Which is not necessarily the best route towards
the target unless you somehow translate the metrics between both
sides.

> I have in mind to develop a migration strategy for our community mesh
> network which is based on olsr.

The problem is to have consistent routes in BOTH directions.

I think you would need  to export/import the metric of all routes to
the from olsrd to olsrd2 and the other way around. Unfortunately
RFC3626 (olsr) does not support metric costs for attached networks.
There might be also the problem with gateway selection and NAT.

if you have two compact "islands" of olsrd and olsrd2, it might
work... e.g. starting to replace nodes around one internet gateway and
only replace a continuous group of nodes around it.

The real horror of these scenarios is if you need a route that will be
flipping back and forth between small patches of olsrd and olsrd2. I
am not sure how to get consistent routing in this case.

Henning