In the MPLS Traffic Engineering chapter (Chapter 2), we saw how MPLS traffic engineering (TE) allows the user to create end-to-end paths across the network with bandwidth reservations. This guarantees that the resources are available to carry traffic of volume less than or equal to the bandwidth reservation. A disadvantage of the basic MPLS-TE model is that it is not aware of the different DiffServ classes, operating at an aggregate level across all of them.
This chapter introduces the concept of DiffServ Aware MPLS-TE, which refines the MPLS-TE model by allowing bandwidth reservations to be carried out on a per-class basis. The result is the ability to give strict QoS guarantees while optimizing use of network resources. The QoS delivered by MPLS DiffServ-TE allows network operators to provide services that require strict performance guarantees, such as voice, and to consolidate IP and ATM/FR (Frame Relay) networks into a common core.
This chapter explores MPLS DiffServ-TE and its extensions. It assumes familiarity with DiffServ in general and MPLS DiffServ in particular, discussed in the Foundations chapter (Chapter 1), as well as with MPLS Traffic Engineering, discussed in the Traffic Engineering chapter (Chapter 2).
4.2 THE BUSINESS DRIVERS
Traditionally, IP/MPLS-based networks were used only for services with relatively relaxed requirements in terms of delay, jitter or bandwidth guarantees. Increasingly, providers have started carrying ...