Subinterfaces divide a single ethernet or port channel interface into multiple logical L2 or L3 interfaces based on the 802.1q or 802.1ad tags of incoming traffic. Subinterfaces are commonly used in the L2/L3 boundary device, but they can also be used to isolate traffic with 802.1q tags between L3 peers by assigning subinterfaces to different VRFs or different L2 bridging domains.