[quagga-users 14843] MULTIPLE ZEBRA INSTANCES

I'm trying to run quagga on mininet because I need OSPF.
 From what I've understood I need a zebra instance and an ospfd instance 
on each switch; since everything is running on the same machine, how do 
I configure each ospf daemon to talk with a difference instance of zebra?

I have another question, what's the meaning of the interface in the 
zebra configuration file?