On-line bandwidth control for quality of service mapping over satellite independent service access points

The Quality of Service (QoS) provision requires the cooperation of all network layers from bottom to top. More specifically, for Broadband Satellite Multimedia (BSM) communications, the physical layers (strictly satellite dependent) are isolated from the rest by a Satellite Independent Service Access Point (SI-SAP), which should offer specific QoS to IP and the upper layers. The structure of SI-SAP and the BSM protocol model “opens the door” to the problem of mapping the performance requests of Satellite Independent layers over Satellite Dependent technology. In such a context, a QoS mapping problem arises when different encapsulation formats are employed along the protocol stack of the SI-SAP interface, for instance, when IP packets are transferred over an ATM, DVB or MPLS core network. In this perspective, we investigate here a novel control algorithm to estimate the bandwidth shift required to keep the same performance guarantees, independent of the technology change. By exploiting Infinitesimal Perturbation Analysis to capture the network performance sensitivity, we obtain an adaptive control law suitable for on-line control on the basis of traffic samples acquired during the network evolution. Owing to the generality of the mathematical framework under investigation, our control mechanism can be generalized for other network scenarios and functional costs.