Benefit of MPLS traffic engineering
Traffic engineering in large IP networks currently uses ATM.
The router network is ATM unaware and hence there are two control planes.
The router control plane has a large number of adjacencies which limits scalability.
MPLS is IP aware and introduces a single IP control plane that matches the physical topology and hence scales better and is simpler.
This is being extended into MP?S (MPLambdaS) to extend Traffic Engineering to the emerging Optical networking plane