[Olsr-users] HNA-filter or multiple instances

[Henning Rogge]

On Sun, Sep 28, 2014 at 4:53 PM, Bastian Rosner <(spam-protected)> wrote:
> Hello,

Hi,

> in Berlin, we have BGP-routers in datacenters with multiple
> network-interfaces. These nodes speak BGP to the outside world while
> some interfaces are directly connected to our WiFi-mesh via OLSR.
> For reasons of simplicity and to use fat-pipes as shortcuts wherever
> possible, we decided to also use OLSR as interior routing protocol to
> interconnect our BGP-servers and their view of the meshi via
> tunnel-interfaces.
>
> Now we are facing issues with HNAs that are only useful for our
> BGP-routers and not for the rest of the city-wide mesh. For example,
> public-IPs that should only be used for connections from the internet
> are now announced inside the mesh.
>
> Is there any way to define HNA for specific interfaces? Or some way of
> filtering incoming HNA so it won't get redistributed?

I am not sure what you mean with "HNA for specific interface".

A router announcing a HNA says "I can route traffic to prefix X". All
other nodes will build a route towards this prefix, otherwise the
hop-by-hop forwarding could fail spectacularly.

> If above approach should not be possible, what about multiple instances
> of OLSRd for different interfaces?

If your group of BGP routers is connected directly without any
"normal" mesh node between them this could work, otherwise you break
the connection, because the intermediate mesh node will not forward
the traffic.

OLSRd2 supports multiple topologies on the same routing agent, but
even with this the intermediate node needs to be part of this
topology.

> Might OLSRd2 be useful and stable enough for the purpose of IGP?

I think its reasonable stable, but I am still waiting for someone
doing the first large scale deployment.

Henning Rogge