3. Conclusions and outlook

MPLS-TE technology enables the establishment of MPLS LSPs called MPLS-TE tunnels, explicitly routed according to traffic engineering constraints such as bandwidth. It introduces a connected mode to IP networks, based on constraint routing and resource reservation. By controlling the paths taken, MPLS-TE enables finer optimization of resource use than conventional IP routing (based on the shortest path to the destination). MPLS-TE reduces the risks and rates of congestion, and can therefore be seen as a mechanism for improving QoS. Guaranteeing bandwidth with MPLS-TE and guaranteeing QoS (delays, etc.) with the DS-TE extension (routing by class of service) requires complementary mechanisms for limiting traffic at the head of the tunnel, combined with mechanisms for adapting tunnel size, and the implementation of such mechanisms remains relatively limited on routers today.

...