MPLS Overview

In conventional IP routing, as a packet traverses from one router to the next through a network, each router analyzes the packet’s header and performs a network layer routing table lookup to choose the next hop for the packet. In conventional IP forwarding, the router looks for the address in its forwarding table with the longest match (best match) for the packet’s destination address. All packets forwarded to this longest match are considered to be in the same forwarding equivalence class (FEC).

MPLS is a hybrid protocol that integrates network layer routing with label switching to provide a layer 3 network with traffic management capability. MPLS provides traffic-engineering capabilities that make effective use of network resources while maintaining high bandwidth and stability. MPLS enables service providers to provide their customers with the best service available given the provider’s resources, with or without traffic engineering. MPLS is the foundation for layer 3 and layer 2 VPNs.

The two basic components of MPLS are label distribution and data mapping.

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