Stacking and Rewriting Gigabit Ethernet VLAN Tags Overview

You can stack and rewrite VLAN tags on the following interfaces:

• Gigabit Ethernet
• Gigabit Ethernet IQ
• 10-Gigabit Ethernet LAN/WAN PIC
• Gigabit Ethernet IQ2 and IQ2-E
• 10-Gigabit Ethernet IQ2 and IQ2-E interfaces, and MX Series router Gigabit Ethernet Interfaces
• Tri-Rate Ethernet copper, and 10-Gigabit Ethernet interfaces with the VLAN encapsulation type configured to support Layer 2 tunneling protocols such as circuit cross-connect (CCC) or virtual private LAN service (VPLS) (as described in 802.1Q VLANs Overview)

Stacking and rewriting VLAN tags allows you to use an additional (outer) VLAN tag to differentiate between customer edge (CE) routers that share one VLAN ID. A frame can be received on an interface, or it can be internal to the system (as a result of the input-vlan-map statement).

Note: On IQ2 interfaces, 10-Gigabit Ethernet LAN/WAN PIC, IQ2-E interfaces, and MX Series interfaces, when a VLAN tag is pushed, the inner VLAN IEEE 802.1p bits are copied to the IEEE bits of the VLAN or VLANs being pushed. If the original packet is untagged, the IEEE bits of the VLAN or VLANs being pushed are set to 0.