Query on mellanox ml2 mechanism driver

Hi!

I read somewhere that mellanox ml2 driver is supposed to replace the openvswitch agent on compute nodes (if one wants to use the SR-IOV technology on mellanox cards). However, I was required to install both openstack-neutron-openvswitch and mellanox packages (ewswitchd and openstack-neutron-mellanox) on compute nodes.

Can someone please clarify as to why is openvswitch still required on compute nodes? Is it just there to receive messages from controller and pass it on to eswitchd?

I will appreciate if someone can point me to any documents that talk about this.

Thanks!