L2VPN communication between sites fail

Products

• VMware NSX

Issue/Introduction

Symptoms:

When using an L2VPN between a standalone Edge client and a Server Edge to stretch a VLAN or VXLAN at the server site to a VLAN at the client site:

• Virtual machines are unable to communicate over the L2VPN even if the tunnel status displays the status as UP.
• Virtual machines are unable to communicate over the L2VPN even if the MAC address of the virtual machines at each site are seen on both edges when running the show service l2vpn command.

Environment

VMware NSX for vSphere 6.3.x
VMware NSX for vSphere 6.2.x
VMware NSX for vSphere 6.4.x

Cause

When creating the sub-interfaces on the trunk interface of the Edge to stretch networks across sites, the tunnel ID must match on both sides for the traffic to be bridged correctly. If there is a mismatch in the tunnel ID, the communication between sites may fail.

Resolution

To check the sub interface details on the server (managed) Edge:

1. Navigate to Edge > Manage > Interfaces.
2. Select the trunk interface and click on the pencil icon. You can see the list of sub interfaces with VLAN /VNI number and the Tunnel ID.

When using a standalone Edge, the VLAN to tunnel ID mapping is defined manually during the configuration, by specifying the tunnel ID in brackets after the VLAN number.

To check the sub interface details on the standalone Edge:

1. Log in to the standalone Edge using SSH or console.
2. Enter enable mode (en).
3. Enter configuration mode ( conf t).
4. Run the show sub-interface command to list the vNIC, index, tunnel ID and Network ID for each sub interface.

If one or more sub interfaces are incorrectly configured, remove the sub interface.

1. Run the no sub-interface pairs 127:127 command to delete sub-interface mapping VLAN 127 to tunnel ID 127.
2. Commit the change by running the commit command.

To create a new sub-interface mapping:

1. Run the sub-interface pairs 127:1 command. Here 127 is the VLAN number and 1 is the Tunnel ID.
2. Commit the change by running the commit command.

Confirm the mappings by running the show sub-interface command.

Additional Information