Linkedin Youtube
Contact us

8 – SONiC QinQ Configuration

Pine Networks > SONiC Configuration > 8 – SONiC QinQ Configuration

SONiC QinQ Configuration

In this article we will explore how to configure VLAN QinQ (802.1ad) on Enterprise SONiC. QinQ allows service providers to encapsulate customer VLAN traffic (C-VLAN) inside provider VLANs (S-VLAN), enabling multiple customers to use overlapping VLAN IDs while maintaining separation.

We will cover:

  • Creating service (S-VLAN) and customer (C-VLAN)
  • Configuring QinQ on interfaces
  • Verification
Test Topology

Creating Customer-VLAN and Service-VLAN

First we create both service and customer VLANs.

On Switch-1
Switch-1# configure terminal
Switch-1(config)# vlan 100
Switch-1(config)# vlan 200
On Switch-2
Switch-2# configure terminal
Switch-2(config)# vlan 100
Switch-2(config)# vlan 200
  • VLAN 100 → Service VLAN (S-VLAN)
  • VLAN 200 → Customer VLAN (C-VLAN)

Configuring QinQ on interfaces

Enable QinQ by assigning customer VLANs to service VLANs.

On Switch-1
Switch-1(config)# interface Ethernet 1
Switch-1(conf-if)# switchport mode dot1q-tunnel
Switch-1(conf-if)# switchport access vlan 100
On Switch-2
Switch-2(config)# interface Ethernet 2
Switch-2(conf-if)# switchport mode dot1q-tunnel
Switch-2(conf-if)# switchport access vlan 100

Assign customer-facing interfaces:

On Switch-1
Switch-1(config)# interface Ethernet 8
Switch-1(conf-if)# switchport access vlan 200
On Switch-2
Switch-2(config)# interface Ethernet 8
Switch-2(conf-if)# switchport access vlan 200

Verification

Use the show Vlan and show interface commands to verify QinQ configuration

Switch-1# show vlan
Q: A - Access (Untagged), T - Tagged
NUM Status Q Ports Autostate Dynamic
100 Active T Eth1  Enable    No
200 Active A Eth8  Enable    No

Check tunneling configuration:

sonic# show dot1q-tunnel
Interface    Mode            VLAN
Eth1         dot1q-tunnel    100
Notes
  • QinQ enables VLAN stacking, useful in carrier and multi-tenant environments.
  • The outer tag (S-VLAN) is used by the provider, while the inner tag (C-VLAN) identifies customer traffic.
  • Make sure both provider and customer VLANs are properly configured and consistent on both ends.
  • Always veirfy using show vlan and show dot1-qtunnel.