What is the best configuration of network interfaces to deploy openstack

So I'm deploying openstack xena using kolla ansible, and i've used infiniband network to connect between the serves of my cluster, however I was wondering whether it is advisable to use a single interface for for " *api_interface*" and "*storage_interface*" and " *tunnel_interface*" or maybe using separate interfaces would be better? Furthermore, I want to ask if using *ipoib *for the infiniband network is a better option than a regular ethernet rg45 network. Thank you all.