VMware HCX Network Extension is a layer-two bridging function initiated at the source site.

You can extend networks by selecting one or more Distributed Port Groups or NSX segments. When you extend a network, a corresponding NSX segment is created at the destination site.
Note:

For a list of restrictions regarding Network Extension, see Restrictions and Limitations for Network Extension.

For the operational limits supported with HCX Network Extension, see Configuration and Service Limits.

Prerequisites

The source and destination site pair are vSphered-based HCX deployments and a Service Mesh is deployed between them.

Procedure

  1. Navigate to Services > Network Extension .
    A summary screen appears displaying all Service Meshes associated with the local HCX Manager. Expand a Service Mesh to see the associated Network Extensions.
    Note: For non-vSphere site pairs, Network Extension is not supported. For these sites, the Service Mesh does not appear in the list for Network Extension.
    1. Click Next.
  2. At the top of the page, select Extend Networks.

    A screen appears prompting you for the target site network selections.

  3. Select a Service Mesh.
    Note: If you have only one Service Mesh, it is selected by default.
  4. Select one or more Distributed Port Groups or NSX Logical Switches.

    You can use the available filters to hide networks that are ineligible for extension, hide networks that do not have virtual machines associated with them, or hide networks without extension.

  5. Using the drop-down menu, select the Destination First Hop Router.
  6. For each source network to extend, provide the Gateway IP address and Prefix Length in the format <gateway IP/Prefix Length>. For example: 192.168.10.1/24.

    For a VMware Cloud Director target cloud, click the extended option drop-down menu and optionally specify the DNS configuration.

  7. Select the Extension appliance.

    Select a Network Extension appliance or a Network Extension High Availability group.

  8. (Optional) For each source network, expand Settings - optional and select the appropriate options:
    Allow Overlapping VLAN

    The HCX Manager prevents you from extending networks that have the same VLAN ID and Gateway IP address. Select this option to override the system and allow duplicate VLAN IDs.

    Allow Overlapping IP Subnet

    By default, HCX blocks attempts to extend the same subnet to the same Tier 1 router at the destination site. Select this option to override the system and allow overlapping IP subnets.

    DNS entries

    For a VMware Cloud Director target cloud, optionally specify the DNS configuration: Primary DNS, Secondary DNS, and DNS Suffix.

  9. (Optional) Depending on the NSX version running in your data center, select Mobility Optimized Networking for all workloads that require routing through the local gateway at the target site.

    For more information about MON and additional configuration settings, see Understanding Network Extension with Mobility Optimized Networking.

  10. To finish, click Submit or Validate.

    Clicking Submit extends the network. To view the task status, navigate to the HCX Dashboard and scroll down to the Activity Logs display.

    Note:

    If any conflicting operations on the same appliances are running, then network extension requests are queued. Examples of conflicting operations include Service Mesh edits or resyncs, appliance operations such as redeploy or force resync, and network extension using the same high availability (HA) group.

    Clicking Validate performs input validations without starting the network extension..

Results

Return to the Network Extension page for a summary of information that includes the number of extended networks, extension appliances, mobility optimized networks, and network extension served by an HA group. The HA group name is used in place of appliance name with an HA tag to indicate the HA activation.