QinQ VLAN tagging in Distributed Switch ESXi

Products

• VMware vSphere ESXi

Issue/Introduction

• QinQ VLAN, also known as IEEE 802.1ad, is a networking technology that allows for the stacking of multiple VLAN tags in Ethernet frames.
• QinQ VLAN allows for an additional VLAN tag to be added to an already tagged Ethernet frame. This results in frames that have two VLAN tags: an outer (or provider) tag and an inner (or customer) tag.

Environment

VMware vSphere ESXi 

Cause

 

 

 

Resolution

• Trunking protocol type for VLAN for VGT in ESXi is 802.1Q
• For QinQ generally the trunking protocol used is 802.1ad
• Thus QinQ having trunking protocol of 802.1ad is not supported on the DVS.
• However our vDS can support the QinQ which has the 802.1Q tag as the outer tag, that is:

                 outer tag: 802.1Q tag (TPID: 0x8100) -- inner tag: 802.1Q tag.

 

Sample Configuration for QinQ (802.1Q)

If 4055 is the outer vlan and 4058 is the inner vlan id,

• Tag 4055 on the Distributed switch portgroup, same as the tag on your physical switch.
• Attach the network adapter of the VM to the above DVS portgroup
• Double tag 4058 inside the guest OS, find the example commands below

 

Double tags configuration command in VMs:

  [root@localhost ~]# ip link add link eth1 eth1.4055 type vlan proto 802.1q id 4055

  [root@localhost ~]# ip link add link eth1.4055 eth1.4055.4058 type vlan proto 802.1q id 4058

Note: This is not QinQ, it's just delivering tagged VLAN with another inside VLAN frame to a guest in trunk mode. We don't support the other types of QinQ, such as:

           outer tag: 802.1ad tag (TPID: 0x88a8) -- inner tag: 802.1Q tag.