Scalable Quasi‐Dynamic‐Provisioning‐Based Admission Control Mechanism in Differentiated Service Networks

The architecture in a differentiated services (DiffServ) network is based on a simple model that applies a per‐class service in the core node of the network. However, because the network behavior is simple, the network structure and provisioning is complicated. If a service provider wants dynamic provisioning or a better bandwidth guarantee, the differentiated services network must use a signaling protocol with QoS parameters or an admission control method. Unfortunately, these methods increase the complexity. To overcome the problems with complexity, we investigated scalable dynamic provisioning for admission control in DiffServ networks. We propose a new scalable qDPM² mechanism based on a centralized bandwidth broker and distributed measurement‐based admission control and movable boundary bandwidth management to support heterogeneous QoS requirements in DiffServ networks.     

Service overlay networks: SLAs, QoS, and bandwidth provisioning

We advocate the notion of service overlay network (SON) as an effective means to address some of the issues, in particular, end-to-end quality of service (QoS), plaguing the current Internet, and to facilitate the creation and deployment of value-added Internet services such as VoIP, Video-on-Demand, and other emerging QoS-sensitive services. The SON purchases bandwidth with certain QoS guarantees from the individual network domains via bilateral service level agreement (SLA) to build a logical end-to-end service delivery infrastructure on top of the existing data transport networks. Via a service contract, users directly pay the SON for using the value-added services provided by the SON. In this paper, we study the bandwidth provisioning problem for a SON which buys bandwidth from the underlying network domains to provide end-to-end value-added QoS sensitive services such as VoIP and Video-on-Demand. A key problem in the SON deployment is the problem of bandwidth provisioning, which is critical to cost recovery in deploying and operating the value-added services over the SON. The paper is devoted to the study of this problem. We formulate the bandwidth provisioning problem mathematically, taking various factors such as SLA, service QoS, traffic demand distributions, and bandwidth costs. Analytical models and approximate solutions are developed for both static and dynamic bandwidth provisioning. Numerical studies are also performed to illustrate the properties of the proposed solutions and demonstrate the effect of traffic demand distributions and bandwidth costs on SON bandwidth provisioning.     

Dynamic core provisioning for quantitative differentiated services

Efficient network provisioning mechanisms that support service differentiation are essential to the realization of the Differentiated Services (DiffServ) Internet. Building on our prior work on edge provisioning, we propose a set of efficient dynamic node and core provisioning algorithms for interior nodes and core networks, respectively. The node provisioning algorithm prevents transient violations of service level agreements (SLA) by predicting the onset of service level violations based on a multiclass virtual queue measurement technique, and by automatically adjusting the service weights of weighted fair queueing schedulers at core routers. Persistent service level violations are reported to the core provisioning algorithm, which dimensions traffic aggregates at the network ingress edge. The core provisioning algorithm is designed to address the difficult problem of provisioning DiffServ traffic aggregates (i.e., rate-control can only be exerted at the root of any traffic distribution tree) by taking into account fairness issues not only across different traffic aggregates but also within the same aggregate whose packets take different routes through a core IP network. We demonstrate through analysis and simulation that the proposed dynamic provisioning model is superior to static provisioning for DiffServ in providing quantitative delay bounds with differentiated loss across per-aggregate service classes under persistent congestion and device failure conditions when observed in core networks.     

Path diversified multi-QoS optimization in multi-channel wireless mesh networks

Wireless mesh networks (WMNs) have become a promising solution for quick and low-cost spreading of Internet accesses and other network services. Given the mesh topology, multiple paths are often available between node pairs, which thus naturally endorse path-diversified transmission. Unfortunately, like in wired networks, discovering completely disjoint paths in a WMN remains an intractable problem. It indeed becomes more challenging given the interferences across wireless channels in a WMN, not to mention that applications may demand heterogeneous QoS optimizations across different paths. The availability of multiple channels in advanced WMNs however sheds new lights into this problem. In this paper, we show that, as long as the best channels with different QoS metrics are not overlapped between neighboring node pairs, complete disjoint paths with heterogeneous QoS targets are available in a multi-channel WMN. We present efficient solutions to discover such paths, particularly for bandwidth- and delay-optimization. We also develop novel algorithms for accurately estimating path bandwidth and delay in the multi-channel environment. These lead to the design of a practical protocol that extends the classical Ad hoc On-demand Multi-path Distance Vector (AOMDV). Through extensive simulations, we show that our protocol yields significant improvement over state-of-the-art multi-path protocols in terms of both end-to-end throughput and delay.     

Space‐time diversity‐enhanced QoS provisioning for real‐time service over MC‐DS‐CDMA based wireless networks

In order to support the quality‐of‐service (QoS) requirements for real‐time traffic over broadband wireless networks, advanced techniques such as space‐time diversity (STD) and multicarrier direct‐sequence code division multiple access (MC‐DS‐CDMA) are implemented at the physical layer. However, the employment of such techniques evidently affects the QoS provisioning algorithms at the medium access control (MAC) layer. In this paper, we propose a space‐time infrastructure and develop a set of cross‐layer real‐time QoS‐provisioning algorithms for admission control, scheduling, and subchannel‐allocations. We analytically map the parameters characterizing the STD onto the admission‐control region guaranteeing the real‐time QoS. Our analytical analyses show that the proposed algorithms can effectively support real‐time QoS provisioning. Also presented are numerical solutions and simulation results showing that the STD can significantly improve the QoS provisioning for real‐time services over wireless networks. Copyright © 2007 John Wiley & Sons, Ltd.     

Provisioning of multimedia services in 802.11-based networks: facts and challenges

QoS provisioning in IEEE 802.11 networks is a nontrivial task due to a certain degree of randomness in the contention-based medium access control protocol. The problem often resides in the fact that flows belonging to the same service class use the same MAC parameters regardless of their respective bit rates. Assigning static MAC parameters confines WLAN deployment possibilities, and often leads to throughput fairness rather than perceived QoS fairness. This creates situations where network resources as well as their potential profitability are underex-ploited. Restricting the volume of traffic load carried by the network is a primordial task in order to preserve QoS performances of active multimedia services. In this article we review existing approaches to deliver QoS to real-time services in order to gain thorough insight into inhibiting factors inherent to contention-based 802.11 networks. The emphasis is put on studying the possible means to sustain QoS guarantees, which is of utmost importance for network operators willing to commit theirs underlying resources through service level agreements.     

Differentiated integrated QoS control in the optical Internet

In order to facilitate convergence of networks and services, this article investigates a new hybrid and integrated QoS control scheme that combines electrical IP layer features with reconfigurable optical layer, and addresses cross-layer design on QoS control in optical Internet (i.e., IP/WDM networks). The proposed integrated QoS control scheme can not only provide appropriate transport service for various types of traffic relating to different service categories in a cost-effective way, but also maintain high flexibility/scalability for integrated services provisioning, which seems to be preferred for QoS provisioning in the next-generation multiservice integrated optical Internet.     

A call admission control framework for voice over WLANs

In this article a call admission control framework is presented for voice over wireless local area networks (WLANs). The framework, called WLAN voice manager, manages admission control for voice over IP (VoIP) calls with WLANs as the access networks. WLAN voice manager interacts with WLAN medium access control (MAC) layer protocols, soft-switches (VoIP call agents), routers, and other network devices to perform end-to-end (ETE) quality of service (QoS) provisioning and control for VoIP calls originated from WLANs. By implementing the proposed WLAN voice manager in the WLAN access network, a two-level ETE VoIP QoS control mechanism can be achieved: level 1 QoS for voice traffic over WLAN medium access and level 2 QoS for ETE VoIP services in the networks with WLANs as the local access. The implementation challenges of this framework are discussed for both level 1 and level 2. Possible solutions to the implementation issues are proposed and other remaining open issues are also addressed.     

QoS provisioning in wireless video sensor networks: a dynamic power management framework

Recent technological advances in microelectronics and nano-systems technologies have made it feasible to equip wireless sensor nodes with small low-cost cameras to capture and transmit video. Wireless video sensor networks are gaining popularity due to numerous potential applications such as video surveillance, environmental and habitat monitoring, and so on. However, due to the limited battery available in wireless video sensor nodes, provisioning of QoS in such a network is a challenging task. We provide a survey on the major issues related to QoS provisioning in wireless video sensor networks and possible solution approaches. A dynamic power management framework is proposed for a wireless video sensor node to improve energy saving performance so that the lifetime of the sensor node can be increased. This framework considers the video traffic arrival process in the sensor node, the sleep and wakeup processes in the camera and wireless transceiver electronics, the queue status, and the wireless channel condition. Performance analysis results show that the proposed mechanism can achieve considerable energy saving in a sensor node while providing a target level of QoS performance.     

Optimized routing for providing ethernet LAN services

Ethernet's-move into metropolitan and wide area networks is driving a rapidly growing market opportunity. Current Ethernet services come in two basic flavors, Ethernet line and LAN, providing point-to-point and multipoint connectivity, respectively. The LAN services, although more cost effective, are lagging behind in deployments due to associated QoS and bandwidth provisioning issues. The Ethernet service provider needs to provision the network to meet current and future traffic demands, where the traffic is unpredictable and bursty. The goal is to minimize. overprovisioning and complexity. To add to the challenge, Ethernet routing is based on simple self-learning and relies on spanning tree routing. In this article we propose an Ethernet-specific load balanced routing mechanism, which is robust to dynamic traffic demand. It significantly reduces overprovisioning, is simple and static, and requires only bandwidth profiles associated with service level agreements at the ingress and egress links. Our simulation results show that our scheme provides performance improvements over a recently proposed approach for switched Ethernet as well as a related load balancing approach for Ethernet over MPLS networks.     

Adaptive QoS Management for IEEE 802.11 Future Wireless ISPs

Wireless Internet Service Providers (WISPs) are expected to be the new generation of access providers using the emerging IEEE 802.11 technology. Face to the high competition of providing network services, the WISP have to offer the best service to the users. For this purpose, the WISP networks' managers need to provide Quality of Service (QoS) with a minimum cost in their wireless networks. The current link layer IEEE 802.11b provides fair sharing of the radio resource with no service differentiation mechanism; similarly to the Internet best effort service. However, the ongoing standard IEEE 802.11e should implement a priority mechanism at the link layer to differentiate the users' traffic. In order to overcome the lack of differentiated mechanism in the current link layer IEEE 802.11b, hence controlling the utilization of the scarce radio resource, we propose in this article to deploy Diffserv architecture coupled with an adaptive provisioning of QoS to provide better services to the users with minimum WISP cost and improve the utilization of the radio resource. Compliant with the current and future IEEE 802.11 link layer, the proposed adaptive QoS provisioning mechanism reacts to the radio resource fluctuation and improves the number of accepted clients in the IEEE 802.11 wireless cells based on the WISP business policies. The network layer differentiation provided by the Diffserv architecture intends to control the concurrent access of the traffic to the scarce radio resources at the IP layer of the mobile hosts for the uplink traffic on one hand, and at the IP layer of the base stations for the downlink traffic on the other hand.     

Soft QoS provisioning using the token bank fair queuing scheduling algorithm

Future-generation wireless packet networks will support multimedia applications with diverse QoS requirements. Much of the research on scheduling algorithms has been focused on hard QoS provisioning of integrated services. Although these algorithms give hard delay bounds, their stringent requirements sacrifice the potential statistical multiplexing performance and flexibility of the packet-switched network. Furthermore, the complexities of the algorithms often make them impractical for wireless networks. There is a need to develop a packet scheduling scheme for wireless packet-switched networks that provides soft QoS guarantees for heterogeneous traffic, and is also simple to implement and manage. This article proposes token bank fair queuing (TBFQ), a soft scheduling algorithm that possesses these qualities. This algorithm is work-conserving and has a complexity of O(1). We focus on packet scheduling on a reservation-based TDMA/TDD wireless channel to service integrated real-time traffic. The TBFQ scheduling mechanism integrates the policing and servicing functions, and keeps track of the usage of each connection. We address the impact of TBFQ on mean packet delay, violation probability, and bandwidth utilization. We also demonstrate that due to its soft provisioning capabilities, the TBFQ performs rather well even when traffic conditions deviate from the established contracts.     

Designing scalable on-demand policy-based resource allocation in IP networks

Today, the policy-based management approach is recognized as an efficient solution to simplify the complex task of managing and controlling networks. To this end, the IETF has introduced a reference framework to build PBM systems. However, this framework only addresses the provisioning of relatively long validity period services based on pre-defined service level agreements. Furthermore, very little work addresses the scalability properties of the instantiation of this framework in a real network. This work aims to extend the IETF PBM framework in order to support dynamic provisioning of short term services (end system signaling) as well as an instantiation scheme that is scalable (distributed provisioning of edge routers). This instantiation scheme is based on the distribution of the provisioning process while keeping centralized only the parts that involve critical resources, that is, the bandwidth brokerage. The performance properties of the proposed scheme are then demonstrated throughout both extensive experimentation and a short analytical study. The results of this work are intended to be used as a guideline to help network operators to design scalable PBM system in order to offer to their customers services with QoS assurance in an on-demand basis.     

A Per-Flow Based Node Architecture for Integrated Services Packet Networks

As the Internet transforms from the traditional best-effort service network into QoS-capable multi-service network, it is essential to have new architectural design and appropriate traffic control algorithms in place. This paper presents a network node architecture and several traffic management mechanisms that are capable of achieving QoS provisioning for the guaranteed service (GS), the controlled-load (CL) service, and the best-effort (BE) service for future integrated services networks. A key feature of our architecture is that it resolves the out-of-sequence problem associated with the traditional design. We also propose two novel packet discarding mechanisms called selective pushout (SP) and selective pushout plus (SP+). Simulation results show that, once admitted into the network, our architecture and traffic management algorithms provide, under all conditions, hard performance guarantees to GS flows and consistent (or soft) performance guarantees to CL flows, respectively; minimal negative impact to in-profile GS, CL and BE traffic should there be any out-of-profile behavior from some CL flows.     

An Effective QoS Differentiation Scheme for Wireless Mesh Networks

Wireless mesh networking is emerging as an important architecture for future-generation wireless communications systems. Quality of service provisioning is a challenging issue in WMNs. In this article we study an effective QoS differentiation scheme for IEEE 802.16 WiMAX mesh networks. Both collocated and general topologies are exploited. Illustrative numerical examples are presented to demonstrate the effectiveness of the proposed strategy. The impact of key parameters on performance is discussed for differentiating various services. Moreover, with the proposed scheme, WMN scalability can be greatly improved. The challenges with respect to the integration of WMN and cooperative transmission are discussed, and the fairness problem is addressed with potential solutions.     

SNMP-based acquisition system for DiffServ parameters

Modern communication networks cannot get along without quality of service (QoS) assurance. QoS-support mechanisms offer preferential treatment for specific traffic classes that is required especially by real-time network applications. Unfortunately current QoS technologies have certain disadvantages and limitations and therefore they are not always able to guarantee the required QoS level. This paper introduces a quality of service support system that improves the most often used quality of service support technology called Differentiated Services (DiffServ). The system proposed utilizes the Simple Network Management Protocol (SNMP) for the acquisition of configuration information from the edge router of the DiffServ domain. This information is subsequently used to control the allocation of network resources within the QoS assurance process. In order to evaluate this system we used the OPNET Modeler simulation environment where we built a simulation scenario able to interact with real network components. For this purpose we implemented the SNMP protocol into the OPNET Modeler and used it for acquisition of management information, stored in the Management Information Base (MIB) of the network node. The paper describes in details the improved QoS-support mechanism and the simulation model able to cosimulate the behavior of both real and virtual network elements.     

基于智能业务识别的可信路由研究

本文研究并提出了基于智能业务识别与控制的可信路由架构.该架构根据动态配置的安全/Qos策略,在智能业务分类与识别的基础上,标记数据包,执行业务流量自适应调节与控制,并采用队列管理和调度管理,实现可信Qos路由.此外,本文综合了端口匹配法的简单、快速、复杂度低和灵活性好,净荷分析法的精确有效,以及流量特征分析法可扩展性好等特点,提出并建立了实时智能网络业务分类系统.该系统具有较高精度、低计算复杂度、良好的可扩展性、早期检测和鲁棒等优点,是高速链路可信路由的前提和保障.     

Enabling novel premium service classes in DiffServ over MPLS‐enabled network

Network resources dimensioning and traffic engineering influence the quality in provisioned services required by the Expedited Forwarding (EF) traffic in production networks established through DiffServ over MPLS‐enabled network. By modeling EF traffic flows and the excess of network resources reserved for it, we derive the range of delay values which are required to support these flows at DiffServ nodes. This enables us to develop an end‐to‐end (e2e) delay budget‐partitioning mechanism and traffic‐engineering techniques within a framework for supporting new premium QoS levels, which are differentiated based on e2e delay, jitter and loss. This framework enables ingress routers to control EF traffic flow admission and select appropriate routing paths, with the goal of EF traffic balancing, avoiding traffic congestion and getting the most use out of the available network resources through traffic engineering. As a result, this framework should enable Internet service providers to provide three performance levels of EF service class to their customers provided that their network is DiffServ MPLS TE aware. Copyright © 2008 John Wiley & Sons, Ltd.     

Pricing for QoS-enabled networks: A survey

A complete solution to the problem of providing adequate quality of service (QoS) to heterogeneous users must take into account the issue of pricing. By adopting an appropriate pricing policy and by setting prices carefully, a service provider will be able to offer the necessary incentives for each user to choose the service that best matches his⁄her needs, thereby discouraging over-allocation of resources and maximizing revenue and⁄or social welfare. In this article, we survey some of the recent research in the literature dealing with service pricing in multi-service networks. All of the work surveyed here addresses the relationship between prices and traffic management functions such as congestion control, resource provisioning, and call admission control. We summarize proposed pricing policies for the Internet and for ATM networks, as well as some studies of pricing for general QoS-enabled networks.     

Cadenus: creation and deployment of end-user services in premium IP networks

Current trends in the information and communications technology industry clearly indicate the existence of a business requirement for a market-enabling technology that allows network operators to interact with users in a seamless, transparent manner for the sale and delivery of a wide range of services with guaranteed quality of service. In this context the need arises for the dynamic creation, configuration and delivery of services with QoS guarantees via the automated management of service level agreements. The aim of the Cadenus project is to bring theoretical and practical contributions to this area by defining a framework for the provisioning of advanced communication services in premium IP networks. Such networks might be characterized by a high degree of complexity, in terms not only of scale, but also of number of operators and technological heterogeneity. Our contribution is twofold, comprising both the design of the proposed framework and its actual implementation. An innovative approach was taken to framework design, based on the concept of mediation. With respect to the framework implementation, an example illustrating the realization of a virtual private network scenario is presented.