After migrating the logical configurations to NSX-T Data Center, the migration coordinator can prepare the required infrastructure to extend the networks between hosts that are still on NSX Data Center for vSphere and hosts that are migrated to NSX-T.

The Layer 2 extension allows the migration coordinator to migrate the environment without disrupting the connectivity between the VMs on NSX-v hosts and the VMs on hosts that are migrated to NSX-T.

In the Prepare Infrastructure step, the following tasks happen in the background:
  • Migration coordinator enables the Controller Disconnected Operation (CDO) mode in NSX-v. The NSX-v NSX Manager creates a special CDO logical switch with VNI 4999 on the NSX-v controller. This VXLAN Network Identifier of the special CDO logical switch is unique from all other logical switches. When the CDO mode is enabled, any one NSX-v controller in the Controller Cluster collects the VXLAN Tunnel Endpoint (VTEP) information reported from all NSX-v prepared hosts, and replicates the updated VTEP information to all other NSX-v hosts. After detecting the CDO mode, broadcast packets such as, ARP, GARP, and RARP are sent to the global VTEP list. By enabling the CDO mode, vMotion of VMs can occur without any data plane connectivity issues when the NSX-v control plane fails.
  • Migration coordinator takes the NSX-v VTEP table and pushes it to the Central Control Plane (CCP) service, which is running on the NSX-T NSX Manager appliance.


  • In the NSX-v environment, NSX Controller Cluster is up.
  • In the NSX-T environment, Central Control Plane (CCP) service on the NSX Manager appliance is up.


  1. On the Prepare Infrastructure page, click Start.
  2. After the infrastructure preparation is finished, click Continue to proceed to the Migrate Hosts page.
    If the infrastructure preparation fails, resolve the errors, click Rollback to roll back the migration, and start the Prepare Infrastructure step again. For example, infrastructure preparation might fail due to the following reasons:
    • NSX-v Controllers are down.
    • NSX-T CCP service on the NSX Manager appliance is down.