Unexpected IPv6 address are seen on untagged interface when edge receives VLAN-tagged RA (Router Advertisement) packets

Products

• VMware VeloCloud SD-WAN

Issue/Introduction

When edge receives VLAN-tagged RA (Router Advertisement) packets, IPv6 addresses are created on untagged interface.

This issue occurs in the below condition.

• Edge interface is untagged.
• On the interface, IPv6 Settings > Addressing Type  set as DHCP
• On the interface, L2 Settings set as auto-negotiation.
• Edge receives VLAN-tagged RA (Router Advertisement) packets on the interface.

On Remote Diagnostics > Interface Status, You can see IPv6 addresses which should be created on VLAN tagged interface.

Environment

Velocloud SDWAN, VMware SDWAN, IPv6, Auto-Negotiation

Cause

This issue occurs when VLAN packets are received on an auto-negotiation interface that does not have VLANs.

Resolution

To solve this, the following workarounds can be implemented:
-    Set a dummy sub interface on the physical interface.
-    Set the address type as Static.
-    Disable auto-negotiation on the interface.