RIP and directly connected routes

[pavel.tvrdik at nic.cz]

Hi Olivier!

On 2015-03-10 10:52, olivier a wrote:
> I'm studying RIP and have a really hard time understanding the
> rationals behind to automatically pulling directly connected routes.
>  If I connect 4 RIP routers in a circle and neither is advertising
> it's connected routes, it's going to be very quiet ...
>  Please help me understand :-)

Yes, you have to configure directly connected routers using 'protocol 
direct' or 'protocol static' for each router otherwise it will be quiet.


> Secondly, I use 'protocol direct' to have these connected routes
> pulled from kernel tables to RIP and advertised. Is that the right way
> to do it ?

Yes, this is a fine solution.


> Lastly, these 'protocol direct' routes override the split horizon
> rule. Is there a way to prevent an interface to multicast its own
> subnet ?

The RIP uses a split-horizon routing with poison reverse, so the routes 
that are not in own subnet will send with metric infinity (in default 
with metric 16). This works well even with 'protocol direct' for me now. 
Are you sure the split horizon rule is overriden in your case? Maybe try 
connect routers in a simple line not in a circle.

Best Regards,
Pavel