MPLS is a technology used by many service providers to increase the efficiency of packet networks. The ‘traffic engineering’ capability further enhances the effectiveness and value of MPLS.

 

At the edge of the Global Crossing network there are routers called ‘edge routers’ and routers in the core of the network called WAN routers. The edge routers move traffic in and out of the network, and the WAN routers are responsible for directing it across the network. With MPLS, the edge routers insert in each packet an MPLS header that contains a label with instructions that enable the wan routers to move the packet efficiently from router to router.

 

The MPLS header also specifies the class of service a packet receives. The packets in a VoIP call, for example, always get the highest class of service, i.e. the highest priority, in our network. If traffic flow over a particular path is reduced by a problem in the network and packets begin backing up in queue, the VoIP packets will get first priority for passage.

Traffic engineering, or MPLS te, represents another layer of control and brings a whole new level of reliability to the Global Crossing MPLS network. In MPLS networks without traffic engineering, packets with lower classes of service may get dropped or discarded if a troubled path fills up. Traffic engineering specifies slightly longer, somewhat less efficient paths for these lower priority packets to follow, but paths that will nonetheless get them to their destinations.

“It’s like getting displaced on an overbooked flight,” Brown says. “First-class passengers, who pay for special treatment, will be first to board. Some of the other passengers may find themselves on another flight that makes more stops than the one they were trying to get on, but it will eventually get them to their destination without a major delay - like spending the night in the terminal.”

Brown points out that MPLS-te is a powerful and complex technology with many additional attributes and capabilities. “It is a key differentiator for Global Crossing,” Brown says, “and it gives our network resilience and economies that competitors have a hard time matching.”