Loss of traffic during ODL Cluster reboot

All ARP requests for VM/MIP IP addresses in L3VPN service are presently handled by the ODL controller. The controller directly responds to ARP request for subnet gateway address while other ARP requests are resolved by the flooding to the E-LAN broadcast group. This approach results in ARP requests not being resolved whenever the ODL is not available or a significant loss of traffic during a cluster reboot until all subnet gateway addresses are relearnt.