HCX Network Extension may be prevented, disallowed, or allowed under explicit conditions.

Detected and Restricted Source Network Types

The HCX Network Extension service detects and prevents several non-supported Network Extension scenarios (items are dimmed in the Network Extension UI):
  • vSphere cluster infrastructure networks (ESXi VMkernel networks).
  • HCX Network Profile networks (Distributed Port Groups or Segments selected in a Network Profile).
  • Trunk networks (Distributed Port Groups with VLAN type Trunk).
  • Untagged networks (Distributed Port Groups with VLAN type None, ID 0 or NULL).
  • HCX Network Extension does not support Private VLAN (PVLAN) networks.
  • HCX Network Extension does not support port groups configured with ephemeral binding.
  • Virtual machine networks with shared or overlapping VLAN configurations should not be extended to the same destination router. This can result in a network outage.

Unsupported Source Configurations

HCX Network Extension does not support the following source configurations:

  • vSphere Standard Switch (VSS) networks.
  • Cisco NSX1000v or other third-party switches.
  • Cisco Application Centric Infrastructure (ACI) with VMware Virtual Machine Monitor (VMM).
  • vSphere Distributed Switches configured with LACP.
  • Daisy-chaining a single network to three separate destination sites is not supported. For example, A to B to C to D is not supported.
  • Virtual machine networks must only be extended with a single solution. HCX does not support Network Extension for networks already extended to the same NSX router by an external solution. For example, HCX Network Extension or NSX L2 VPN can be used to provide connectivity, but both must not be used simultaneously . Using multiple bridging solutions simultaneously can result in a network outage.

Unsupported Destination Configurations

HCX Network Extension does not support the following destination configurations:

  • NSX-T Global Federation configurations.

    HCX does not integrate with the NSX Global Manager (only the NSX Local Manager).

  • NSX-T environments without a Tier 1 Router.
  • NSX-T environments without an Overlay Transport Zone.
  • Destination environments without NSX-T.

Additional Considerations

  • HCX supports one Network Extension to a maximum of 3 distinct destinations or routers.
  • One HCX Network Extension configuration cannot be extended multiple times to the same destination/router
  • One HCX Network Extension appliance can only connect to one Distributed Virtual Switch or NSX Transport Zone.
  • One HCX Network Extension configuration cannot use multiple HCX Network Extension appliances.
  • HCX Network Extension does not detect or mitigate loops.
  • Virtual machine networks that span more than one vCenter Server should not be extended from more than one vCenter to the same destination router. This can result in a network outage.
  • HCX Network Extension does not detect or mitigate IP conflicts on the network.
  • HCX Network Extension does not detect or mitigate MAC conflicts on the network.
  • For a cloud/site pair, a given network can be extended through only one appliance and is subject to the resource and performance limitations of that appliance.
  • When a network is extended using an incorrect gateway IP or Prefix List, unextending and re-extending with the correct information will fail due to the mismatch on the NSX gateway configuration at the destination. In this case, it is necessary to manually remove the previous network extension configuration from the NSX gateway.