Layer 2.5 - MPLS

MPLS stands for MultiProtocol Label Switching. This layer is in between the Data Link Layer and the Network layer. It is not really part of the OSI model but aids in describing the operation of MPLS. MPLS modifies the Data Link layer frame with labels to aid in routing the data.

MPLS Cloud

Multiprotocol Label Switching (MPLS) is used in telecommunications networks that directs data from one network node to the next based on short path labels rather than long network addresses. This simplifies the lookups in the routing table. The labels identify virtual links (paths) between distant nodes rather than endpoints. MPLS can encapsulate packets of various network protocols including legacy protocols such as T1/E1, ATM, Frame Relay, and DSL.

MPLS Label

MPLS is used to connect Service Providers to Service Providers and to connect LANs through virtual cloud WANs together. Packet-forwarding decisions are made solely on the contents of this label, without the need to examine the packet itself. This allows one to create end-to-end circuits across any type of transport medium, using any protocol. The primary benefit is to eliminate dependence on a particular OSI model data link layer . It was designed to provide a unified data-carrying service for both circuit-based clients and packet-switching clients which provide a datagram service model.

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Copyright July 2013 Eugene Blanchard