Multiprotocol Label Switching (MPLS)
The idea behind Multiprotocol Label Switching (MPLS) is simple. In datagram switching each packet is treated as an independent element by routers. If one implements a Differentiated Services architecture, each independent packet is treated according to a policy specifically for its service class. In MPLS, on the other hand, the basic unit is a “flow”. Packets belonging to a given source destination flow within an MPLS cloud of a network have a label(s) appended to the packet that is used by routers along a specified path to relay the packet from router to router.