Real-time scheduling with quality of service constraints

Abstract

Can the introduction of tra c classes improve upon the performance of ATM networks? We investigate this issue within the framework provided by a class of networks that guarantees quality of service. To provide a meaningful comparison we de ne the concept of schedulable region, a region in the space of loads for which the quality of service is guaranteed. We show the dependence of the schedulable region on the scheduling algorithm employed, the quality of service parameters and the tra c statistics. An e cient real-time scheduling algorithm is introduced that substantially increases the schedulable region without incurring prohibitive complexity costs. The schedulable region associated with this algorithm is compared with the ones generated by the static priority scheduling algorithm and a variant of the minimum laxity threshold algorithm. The size and shape of the schedulable region is explored by means of simulations.

A Generic Service Management Architecture for Multimedia Multipoint Communications

“…A service class is defined in the same terms for multimedia resources [6]. The schedulable region of a resource is "the set of points in the space of possible loads for which a given quality of service is guaranteed" [6]. The possible loads of interest for a network are traffic classes.…”

“…For instance, the most stringent traffic class is characterized by 0% as error rate, and no processing duration so that packets received at the resource interfaces are not subject to queuing. A service class is defined in the same terms for multimedia resources [6]. The schedulable region of a resource is "the set of points in the space of possible loads for which a given quality of service is guaranteed" [6].…”

“…Resources capabilities are to be considered. In this respect two appropriate tools, borrowed from [6] and [7], can assist in the estimation of resources capabilities versus the services these resources are able to carry out. Those tools are schedulable region (SR) for network resources and multimedia capacity region (MCR) for multimedia resources.…”

Customer Management and Control of Broadband VPN Services

“…On the cell-level, multiplexing gains among calls with the same source-destination pair (with respect to. the VPN) can be achieved using the schemes described in [HYM91,ELW93]. Cell multiplexing among calls with different source-destination pairs can be performed based on the contract region concept [HYM94].…”

Dynamic QoS-Aware Coalition Formation

“…There is a lot of research on end-to-end architectures for QoS support [8][5] [20][10] and on link, network and transport layers [22] [19]. Some of this research has been focused in low-level systems' mechanisms.…”