Generally, with a limited number of fixed priorities ( ) within a network, applications sharing a same priority are scheduled according to First in First out ( I O) discipline. This policy is called FP/FIFO. However real time applications have deadline requirements which aren’t taken into account with the I O discipline. That is why we propose to introduce the Earliest Deadline First ( D ) disc...

Quality of service (QoS) is a key problem in wireless environments where bandwidth is scarce and channel conditions are time varying and sometimes highly loss. Although IEEE 802.11 wireless LAN (WLAN) is the most widely used WLAN standard today, and the upcoming IEEE 802.11e QoS enhancement standard exists and introduces the QoS for supporting multimedia applications. This paper compares the pr...

Differentiated Services (DiffServ) is a promising architecture for the next generation Internet due to its highly flexible, scalable and interoperable design. In DiffServ, scheduling disciplines play an important role in achieving service differentiation. In this paper, we extend the average delay analysis of the Probabilistic Priority (PP) scheduling discipline first proposed in [8] to the mul...

Differentiated services (DiffServ) is a promising architecture for the next generation Internet due to its scalable and flexible design. In DiffServ, scheduling disciplines play an important role in achieving service differentiation. In this paper, we extend the average delay analysis of the probabilistic priority (PP) scheduling discipline first proposed in [Proc. 2001 IEEE Workshop on High Pe...

AbsfructThe IEEE 802.6 standard for metropolitan area networks does not provide multiple priority traffic for connectionless data services. A priority mechanism that was considered in earlier versions of the standard showed to be not effective. As of now, there exists no protocol for multiple access dual bus networks that is able to implement preemptive priorities and, at the same time, can sat...

This article presents the Load-Level-Based Admission Control mechanism (LLAC) proposed to provide quality of service for optical burst-switched networks. The LLAC mechanism admits bursts of a given service class according to the network load and a class-associated parameter. Based on this parameter, called load level, the proposed mechanism differentiates the burst blocking probability experien...

Abstract: We propose new approximate formulas for the distribution functions of the delay in batch arrival M/G/1 nonpreemptive and preemptive resume priority queues. It is assumed that the delay consists of the waiting time and the service time of a whole batch. Our formulas are of the exponential distribution type with the coefficients being matched with the exact mean and second moment of the...

ÐIn a hard real-time system, it is assumed that no deadline is missed, whereas, in a soft or firm real-time system, deadlines can be missed, although this usually happens in a nonpredictable way. However, most hard real-time systems could miss some deadlines provided that it happens in a known and predictable way. Also, adding predictability on the pattern of missed deadlines for soft and firm ...

Real-time transmission of high-quality JPEG images is constrained by time, bandwidth, and transmission power in portable devices. To alleviate this problem, we designed, implemented, and evaluated a strategy that can adapt to different compression and transmission rates. (1) It gives important parts of an image higher priorities over unimportant parts. Therefore, the high-priority parts can ach...

The objective ofthis paper is to study a communication system based on a M(X)/D/1 queueing system representing a cell-switch network like Asynchronous Transfer Mode (ATM) network. Network structure consists of a single link modeled as a batch arrival markovian queue with non-preemptive head of the line priority service. Network manager (NM) is assumed to be a decision maker at a Management Info...