MPLS (Multi Protocol Label Switching) provides the IP environment without connectivity with a degree of control that was previously the reserve of technologies based on connections such as frame relay and ATM. MPLS is based on packet switching of data, the packets being prefixed with labels; the technology is flexible and versatile because a label may define the path, the source, the destination, the application, the service quality etc.
First of all, MPLS makes it easier to transport the packets over preconfigured routes, according to criteria such as low congestion, load spreading over several routes or the need to restore a link in less than 60 milliseconds in case of circuit breakdown, etc. The intermediate systems at the centre of the network handle the primary information contained in the labels much faster, since the routing decision is made in advance. The packets are therefore transported faster and the router and switching resources are required less.
An MPLS label can be associated with a specific application flow, distinguishing it from others, unlike the IP protocol which sees no difference between applications.
Because an MPLS label can be associated with a source and/or destination, it is easier to create private virtual circuits that share a common physical infrastructure. In addition, with the MPLS label hierarchy, VPNs can be built that do not require any modification to the client IP address plan while co-existing with the MPLS network that some of them may set up between their sites.