Multi-Protocol Label Switching

While almost all the words in its name have changed importance or meaning since multi-protocol label switching (MPLS) was invented, it has become an increasingly important technique in communications networks. Originally, it was seen as a faster means of packet forwarding than IP routing, using locally significant labels rather than globally significant addresses. Originally, IP was not dominant, so it could handle other protocols.

As it developed, however, it has been displacing Asynchronous Transfer Mode (ATM), a method of forwarding fixed-length "cells" with locally significant identifiers, rather than variable-length packets with locally significant identifiers. It has been called "ATM without cells", as it does share the virtual circuit orientation of ATM as opposed to the datagram orientation of classic IP.