Q-in-Q Tunneling on ACX Series Overview

Q-in-Q tunneling allows service providers to create a Layer 2 Ethernet connection between two customer sites. Providers can segregate different customers’ VLAN traffic on a link (for example, if the customers use overlapping VLAN IDs) or bundle different customer VLANs into a single service VLAN. Service providers can use Q-in-Q tunneling to isolate customer traffic within a single site or to enable customer traffic flows across geographic locations.

Q-in-Q tunneling adds a service VLAN tag before the customer’s 802.1Q VLAN tags. The Juniper Networks Junos operating system implementation of Q-in-Q tunneling supports the IEEE 802.1ad standard.

In Q-in-Q tunneling, as a packet travels from a customer VLAN (C-VLAN) to a service provider's VLAN (S-VLAN), another 802.1Q tag for the appropriate S-VLAN is added before the C-VLAN tag. The C-VLAN tag remains and is transmitted through the network. As the packet exits from the S-VLAN space, in the downstream direction, the S-VLAN 802.1Q tag is removed.

In ACX Series routers, you can configure Q-in-Q tunneling by explicitly configuring an input VLAN map with push function on customer facing interfaces in a bridge domain.

You can configure Q-in-Q tunneling on aggregated Ethernet interface by configuring input and output VLAN map.