tag switching - Computer Definition
A layer 3 switching technology from Cisco that is used in large enterprise networks (WANs). It uses tags (labels) containing forwarding information. Tag switching uses routers (Tag Edge Routers) that sit on the periphery of the network and make forwarding decisions for all the routers in the backbone. They append this information to each packet in fixed positions in the header that can be quickly examined by interior backbone routers (Tag Edge Switches), saving the time involved in decoding the packet and its associated table lookups. See MPLS.