HCX Network Extension Traffic Fails Due to Misconfigure NSX L2 Segment

Products

• VMware HCX

Issue/Introduction

• VMware HCX Network Extension is unable to route traffic between the cloud environment and the on-premises environment.
• Virtual machines residing on the cloud-side Network Extension are unable to communicate with virtual machines located on the on-premises Network Extension.
• Running the following API from the HCX  network extension to the NSX manager shows that we are missing the extra config 

curl -k -u 'admin' --request GET --url https://<NSx manager FQDN>/api/v1//infra/segments/hcx-ne-<L2 segment id> --header 'Content-Type: application/json'

• • The below output is missing the extra config 

{
"type" : "DISCONNECTED",
REDACTED
  "advanced_config" : {
    "hybrid" : false,
    "multicast" : true,
    "inter_router" : false,
    "local_egress" : false,
    "urpf_mode" : "STRICT",
    "connectivity" : "OFF"
  },
  "admin_state" : "UP",
  "replication_mode" : "MTEP",
  "resource_type" : "Segment",

• • It should look like this 

{
"type" : "DISCONNECTED",
REDACTED
  "hybrid" : false,
  "span" : [ ],
  "extra_configs" : [ {
    "config_pair" : {
      "key" : "com.vmware.nsx.port.extraConfig.remoteRtr",								<<< Extra Config for L2 MAC Rewrite
      "value" : "1.##.##1 02:50:##48:43:58 02:50:56:56:##:52 02:50:56:##:44:52"
  },
  "admin_state" : "UP",
  "replication_mode" : "MTEP",
  "resource_type" : "Segment",

Environment

• VMware HCX

• VMware NSX

Cause

The advanced_config for the NSX L2 Segment backing the Network Extension is misconfigured or has lost its state, as a result, the cloud Network Extension does not have a functional datapath to establish a communication path to the on-premises Network Extension

Resolution

Workaround- Recreate the network extensions:  

1. Unextend the affected networks within the VMware HCX interface.

   • The user must vacate the L2E Segment on target site prior to deleting the Extended network segment.

2. Delete the associated Network Extension configuration. 

3. Verify and delete the orphaned L2 segments within the NSX Manager UI on the cloud side.

4. Recreate the Network Extension and re-extend the required L2 networks via the HCX interface.