Multiprotocol Label Switching (MPLS) is a standards-approved technology for speeding up network traffic flow and making it easier to manage. MPLS involves setting up a specific path for a given sequence of packets, identified by a label put in each packet, thus saving the time needed for a router to look up the address to the next node to forward the packet to. MPLS is called multiprotocol because it works with the Internet Protocol (IP), Asynchronous Transport Mode (ATM), and frame relay network protocols. With reference to the standard model for a network (the Open Systems Interconnection, or OSI model), MPLS allows most packets to be forwarded at the layer 2 (switching) level rather than at the layer 3 (routing) level. In addition to moving traffic faster overall, MPLS makes it easy to manage a network for quality of service (QoS). For these reasons, the technique is expected to be readily adopted as networks begin to carry more and different mixtures of traffic.
Multi-Protocol Label Switching (MPLS) was originally presented as a way of improving the forwarding speed of routers but is now emerging as a crucial standard technology that offers new capabilities for large scale IP networks. Traffic engineering, the ability of network operators to dictate the path that traffic takes through their network, and Virtual Private Network support are examples of two key applications where MPLS is superior to any currently available IP technology.