ECMP routing configuration Each T0 gateway peers with each ToR switch using BGP, and traffic is distributed across the available edge node VMs using ECMP. The ECMP implementation in VMware NSX-T Data Center limits the number of paths to eight. In the VMware NSX-T Data Center for VxBlock Systems design, each Edge node VM peers with each of the two ToR switches. This pairing limits the maximum number of edge node VMs in the cluster to four. With two edge node VMs, the default configuration is a single T0 gateway with four interfaces. Two interfaces peer with Cisco Nexus 9000 Series Switch 9K-A and two interfaces peer with Cisco Nexus 9000 Series Switch 9K-B. This is the default configuration as delivered – each use case dictates the specific T0 configuration. For more details on the ECMP design, see VMware NSX-T Data Center physical edge cluster. Parent topic Edge ECMP topologyIn VMware NSX-T Data Center for VxBlock Systems, ECMP provides load-balancing across multiple paths northbound from the T0s to the Cisco Nexus 9000 Series ToR switches. VMware NSX-T Data Center supports a maximum of eight paths per edge node cluster.