What is MPLS

MPLS (Multi-propocol Label Switching) is a Multi-Protocol Label exchange.
MPLS is a third-generation network architecture and a new generation of IP High-Speed Backbone Network Exchange Standard, proposed by IETF (Internet Engineering Task Force, Internet Engineering Task Group, led by Cisco, ascend, 3Com, and other network equipment manufacturers.
MPLS is an integrated IP over ATM technology. It combines routing functions on Frame Relay and ATM switch, and data packets are transmitted through virtual circuits. It must be transmitted only on the OSI Layer 2 (data link layer) performs a hardware-based switch (replacing the layer-3 (Network Layer) software-based routing). It integrates the IP address routing and layer-2 tag switching into a single system, so it can solve the Internet routing problem, this reduces the delay time of data packet transmission, increases the speed of network transmission, and is more suitable for the transmission of multimedia messages. Therefore, the biggest technical feature of MPLS is the ability to specify the sequence in which packets are transmitted. MPLS uses Label Switching. The network router only needs to identify the label before forwarding.
The principle of MPLS operation is to provide a tag for each IP packet, and thus determine the path and priority of the packet. A Router compatible with MPLS reads only the packet mark before it forwards data packets to its path, and does not need to read the IP address and header of each packet (so the network speed is faster ), then, the transmitted data packets are placed on the virtual circuit of frame relay or ATM, and the packets are quickly transmitted to the destination router, thus reducing the packet delay, meanwhile, the quality of service (QoS) provided by Frame Relay and the ATM switches grade the transmitted data packets, thus greatly improving the network service quality and providing more diverse services.