QinQ and its application value

As Ethernet technologies are widely used on carrier networks (metro Ethernet networks), the standard VLAN defined in IEEE 802.1q alone cannot completely distinguish between users or isolate a large number of users. This is because the 12-bit VLAN tag field defined in IEEE 802.1q identifies a maximum of only 4096 VLANs.
To expand VLAN tags in quantity, the QinQ technology is developed. It adds another 802.1q tag to a packet that already carries an 802.1q tag. With this technology, the system supports up to 4096 x 4096 VLANs. As metro Ethernet develops and a greater variety of services are deployed, there are more scenarios in which QinQ double tags can be applied. The inner tag (C-VLAN) indicates the user, and the outer tag (SVLAN) indicates the service.

Scroll to top