OSPF question

[mccartab]

Hi everyone ..

I'm looking for some guidance on how best to achieve what's in the attached diagram using OSPF.

The /24 routes advertised to router 1 and router 2 ican be handled with route summarisation but i'm not too sure what the best approach is to then advertise the more specific routes (/28) to router 3 and router 4. 

Thanks

[luis_cordova]

Hi @mccartab 

My recommendation is not to use a summary route in this case.

Why?

Because if networks are summed up, it is possible for packets to be sent in the wrong way, creating congestion on the network. Summary routes are recommended when you have several contiguous networks and a single exit / entry point, for example, at the connection point between different routing protocols.

Regards