What is MPLS / Multi-Protocol Label Switching?
Multi-Protocol Label Switching Multi-Protocol Label Switching (MPLS) provides a mechanism for forwarding packets for any network protocol. It was originally developed in the late 1990s to provide faster packet forwarding for IP routers (see RFC 3031). Since then its capabilities have expanded massively, for example to support service creation (VPNs), traffic engineering, network convergence, and increased resiliency.
MPLS is now the de-facto standard for many carrier and service provider networks and its deployment scenarios continue to grow.
Traditional IP networks are connectionless: when a packet is received, the router determines the next hop using the destination IP address on the packet alongside information from its own forwarding table. The router's forwarding tables contain information on the network topology, obtained via an IP routing protocol, such as OSPF, IS-IS, BGP, RIP or static configuration, which keeps that information synchronized with changes in the network.
MPLS similarly uses IP addresses, either IPv4 or IPv6, to identify end points and intermediate switches and routers. This makes MPLS networks IP-compatible and easily integrated with traditional IP networks. However, unlike traditional IP, MPLS flows are connection-oriented and packets are routed along pre-configured Label Switched Paths (LSPs).