Differentiated service

About: Differentiated service is a research topic. Over the lifetime, 5539 publications have been published within this topic receiving 105225 citations.

Lower and Upper Bounds on FIFO Buffer Management in QoS Switches

Abstract: We consider the management of FIFO buffers for network switches providing differentiated services. In each time step, an arbitrary number of packets arrive and only one packet can be sent. The buffer can store a limited number of packets and, due to the FIFO property, the sequence of sent packets has to be a subsequence of the arriving packets. The differentiated service model is abstracted by attributing each packet with a value according to its service level. A buffer management strategy can drop packets, and the goal is to maximize the sum of the values of sent packets. For only two different packet values, we introduce the account strategy and prove that this strategy achieves an optimal competitive ratio of if the buffer size tends to infinity and an optimal competitive ratio of for arbitrary buffer sizes. For general packet values, the simple preemptive greedy strategy (PG) is studied. We show that PG achieves a competitive ratio of which is the best known upper bound on the competitive ratio of this problem. In addition, we give a lower bound of on the competitive ratio of PG which improves the previously known lower bound. As a consequence, the competitive ratio of PG cannot be further improved significantly.

A QoS MAC protocol for differentiated service in mobile ad hoc networks

Abstract: We propose the prioritized binary countdown (PBC) scheme for effective quality of service (QoS) supports in mobile ad hoc networks. We evaluate the performance of PBC, IEEE 802.11,802.11e, and two extensions to 802.11e in terms of their differentiation capability, throughput, delay, discarding ratio, blocking rate, and collision rate. Our simulation results show that PBC has considerably higher throughput and smaller delay, dropping ratios, blocking rates, and collision rates as compared to CSMA/CA of IEEE 802.11. We also show that PBC have considerably stronger differentiation capability than IEEE 802.11e and its extensions in multihop ad hoc networking environments

The MNM service model — Refined views on generic service management

Abstract: In the last couple of years service management has gained more and more momentum in the research community. Nowadays, as complexity of IT-services is increasing, these services are usually composed of interdependent, layered services hosted by various providers. Therefore, a strong cooperation of providers involved in service provisioning is needed, especially regarding their management processes and systems. One important step is to establish a common understanding about service-related terms in order to be able to specify service functionality and the resulting management tasks. Additionally, means to analyze and identify the necessary actors and the corresponding inter- and intra-organizational relationships are needed. This paper presents an extended version of the MNM service model which provides a generic model defining commonly needed service-related terms, concepts and structuring rules in a general and unambiguous way. Furthermore, we demonstrate the application of the MNM service model by modeling a user help desk service based on a concrete scenario. The experience gained from modeling is used to discuss the benefits of service modeling in general.

Random-access scheduling with service differentiation in wireless networks

Abstract: Recent years have seen tremendous growth in the deployment of wireless local area networks (WLANs). An important design issue in such networks is that of distributed scheduling. The lack of centralized control leads to multiple users competing for channel access. This leads to significant throughput degradation. Existing approaches, such as the slotted Aloha protocol and IEEE 802.11 DCF, also fail to provide differentiated service to users. The upcoming IEEE 802.11e enhanced DCF incorporates additional mechanisms to provide support for service differentiation. However, the level of differentiation achieved with these mechanisms is difficult to quantify. In this paper, we propose a class of distributed scheduling algorithms, regulated contention medium access control (RCMAC), which provides dynamic prioritized access to users for service differentiation in a quantifiable manner. Furthermore, by regulating multi-user contention, RCMAC achieves higher throughput when traffic is bursty, as is typically the case. In addition to WLANs, the basic concepts of RCMAC have applications in ad hoc networks and emerging sensor networks.

Translating Service Level Objectives to lower level policies for multi-tier services

Abstract: Service providers and their customers agree on certain quality of service guarantees through Service Level Agreements (SLA). An SLA contains one or more Service Level Objectives (SLO)s that describe the agreed-upon quality requirements at the service level. Translating these SLOs into lower-level policies that can then be used for design and monitoring purposes is a difficult problem. Usually domain experts are involved in this translation that often necessitates application of domain knowledge to this problem. In this article, we propose an approach that combines performance modeling with regression analysis to solve this problem. We demonstrate that our approach is practical and that it can be applied to different n-tier services. Our experiments show that for a typical 3-tier e-commerce application in a virtualized environment, the SLA can be met while improving CPU utilization by up to 3 times.