Multiprotocol Label Switching
Multiprotocol Label Switching (MPLS) is a mechanism in high-performance telecommunications networks that directs data from one network node to the next based on short path labels rather than long network addresses, avoiding complex lookups in a routing table. The labels identify virtual links (paths) between distant nodes rather than endpoints. MPLS can encapsulate packets of various network protocols. MPLS supports a range of access technologies, including T1/E1, ATM, Frame Relay, and DSL. Introduction MPLS is a scalable, protocol-independent transport. In particular, MPLS dispenses with the cell-switching and signaling-protocol baggage of ATM. At the same time, MPLS attempts to preserve the traffic engineering and out-of-band control that made Frame Relay and ATM attractive for deploying large-scale networks. History MPLS operation A 20-bit label value. These MPLS-labeled packets are switched after a label lookup/switch instead of a lookup into the IP table.