replace l2 population by bgp evpn

Overlay technology like gre/vxlan provide a solution to extend l2 network accross different physical network, but no control plane is introduced in neutron.
BUM (Broadcast, Un-known unicast and multicast) packets will be flooded to all computer nodes, even there is no network allocated on that computer node.
L2 population is to solve this issue, it works in this way:
For example in a data center ,there are C computer nodes, 1 network N1.
When a VM boots up on computer node C1, neutron-server will send all VMs info to computer node C1 in a RPC messages, neutron-server will also send the new VM info to all other computer nodes.
Suppose there are multiple VMs(number is M) boots up simultaneously, the total RPC message will be M * N.
In a big data center, l2 population RPC message will block the message queue, lead the whole control plan hangup