Dynamic hierarchical bandwidth allocation using Russian Doll Model in EPON

This paper demonstrates a new hierarchical Dynamic Bandwidth Allocation algorithm using the Russian Doll Model (RDM) to allocate bandwidth for intra-Optical Network Unit (ONU) in an Ethernet Passive Optical Network (EPON). The allocation of bandwidth is based on the classification and prioritization of service. The algorithm addresses the requests of ONUs and provides differentiated services by balancing priority and fairness. The simulation results show that the proposed algorithm performs well in supporting the triple-play services, i.e. video, voice, and data, as well as making effective adjustment in balancing bandwidth sharing between the ONUs compared with two other existing Dynamic Bandwidth Allocation (DBA) algorithm. The proposed algorithms shows significant performance improvements in terms of bandwidth utilization, packet delay and the fairness.     

Deploying Circuit Emulation Services (CES) Over EPON Using Preemptive Priority Medium Access Controller

Circuit Emulation Services (CES) technology has emerged as an option to mitigate traditional Time Division Multiplexing (TDM) circuits supporting legacy applications across managed packet networks and the Ethernet Passive Optical Network (EPON) is becoming a major technology for pervasive access. The primary benefits of CES over EPON (CESoEPON) are the low cost and simplicity of deployment to support all types of legacy TDM applications across EPONs. Thus, the QoS-guarantee for highly delay-sensitive services on EPONs could be enhanced. This paper investigates a preemptive priority transmission technique that works on MAC and PHY layer of downstream EPONs. The proposed novel scheme effectively reduces the frame queuing delay as well as jitter, so as to enhance precise time synchronization in EPONs. Through simulation experiments, we show that the proposed scheme achieves superior and precise QoS control compared to existing non-preemptive priority methods. A feasible implementation of the proposed solution is also addressed. Finally, we present a general conclusion of the paper as well as address the pros and cons for practical deployment in future works.     

Probabilistic framework and performance evaluation for prioritized call admission control in next generation networks

Next generation networks (NGN) are designed to support a wide range of applications with various service classes (SCs) guaranteeing the respective quality of service (QoS) levels. Since such networks are resource constrained, call admission control (CAC) is imperative to achieve the required QoS levels. In this paper, a new probabilistic framework for CAC schemes is proposed based on controlling each SC independently by admitting low priority SC calls with a variable imposed probability. The incorporation of such a probabilistic framework is considered under a bandwidth-centric approach named probabilistic bandwidth reservation scheme (PBRS). Though equal service times are usually assumed in the literature, the present analysis considers SCs of different service times. By employing Markov chain analysis to treat the independent SCs that correspond to different call specifications, analytical expressions for the call blocking probabilities (CBPs) are derived. The performance of the proposed CAC scheme is studied not only with regard to CBP but, also, taking into account the priorities assigned to different SCs as well as fairness among various SCs and total network throughput. The proposed probabilistic framework allows the dynamic control of network resources considering also priority assignment, fairness and throughput. Analytical results concerning delay tolerant (DT) and delay-non-tolerant (DNT) traffic have been obtained applying the proposed scheme. Moreover, the relevant simulations have verified the accuracy of the proposed analysis.     

Advanced multicast class-based bandwidth over-provisioning

Dynamic bandwidth aggregate over-provisioning has been proposed to provide differentiated services with scalable Quality of Service (QoS) control. Previous research showed that efficient over-reservation control allows minimizing QoS control overhead with reduced waste of bandwidth and blocking probability. However, existing over-reservation centric solutions are still inefficient in the face of network dynamics, as they are not able to accommodate the dynamic service demands, thus failing to optimize the bandwidth usage. This paper proposes a new Advanced Class-based resource Over-Reservation (ACOR) solution for multicast sessions, which seeks increased network resources utilization while minimizing QoS control overhead. More specifically, ACOR is able to dynamically update the share of bandwidth between different classes of service, providing improved results with less complexity than current solutions. Our analytical and simulation results prove the cost-effective and scalable QoS control capabilities of ACOR in decentralized networks with multiple distributed ingress routers coordinating the QoS control.     

A novel pricing approach to support QoS in 3G networks

Pricing in 3G and other communication networks may control and manage the utilisation of network resources. The available network resources get strained with increased usage levels, which results in poor service to the users. Most users prefer receiving high quality services at affordable costs. This requires the provision of QoS guarantees for network services at a low cost. In a real business scenario, this relationship is hard to achieve; moreover revenue sources for network operators have been shifting from the provision of network access to provisioning of rich services, e.g. multimedia services. To attain a functional compromise, we propose a pricing scheme that relies on service profiles to manage resource utilisation in a DiffServ-enabled 3G network. The service profiles define the QoS achieved for accessing services through a common resource pool, in which resource sharing is used to maximise network resource utilisation, user satisfaction and profits for the network operators. In an NGN scenario users would select pricing profiles according to their budgets, and the network will map these profiles to a set of QoS options that may translate to the choice of an access network for service access. In this paper, we present the mathematical model of the proposed pricing scheme, the proposed design of an evaluation framework, QoS performance results, and a service provisioning scenario illustrating the applicability of the proposed pricing scheme.     

Enhancing WLAN/UMTS dual-mode services using a novel distributed multi-agent scheduling scheme

WLAN services are inexpensive and have a high bandwidth, while UMTS services provide wider coverage area and high mobility. Based on intelligent deduction, this study presents a novel service scheduling scheme for WLAN/UMTS dual-mode networks. The proposed system, Distributed Multi-Agent System (DMAS), consists of a set of problem-solving agents that autonomously process their own tasks and interoperate with one another by a shared database to reach a suitable schedule for dual-mode network services. A two-level control mechanism comprising local-control and meta-control is presented to achieve a high degree of goodness in service scheduling. Simulation results indicate that the Quality of Service (QoS) of the proposed discipline in terms of average delay and jitter is better than that of the pure UMTS network by 25% and 10%, respectively. The scheduling discipline can improve the service quality in multiple-mode networks.     

一种业务驱动的多媒体传感器网络路由算法

针对多媒体传感器网络承载业务（视频图像业务、音频业务以及数据业务）的差异性和不同业务对QoS的差异性,基于蚁群算法和混沌理论,抽象业务驱动的QoS路由模型,提出了一种业务驱动的路由算法SDR（Service-Driver Routing）。依据各类业务对QoS的差异性选择相应路由策略,达到充分利用网络资源、提高网络承载业务性能的目标。采用NS2对该算法进行实验仿真,实验结果表明,与其他路由算法相比,该算法可提供区分业务的QoS保障。     

An Efficient Resource Allocation Mechanism for LTE–GEPON Converged Networks

Optical–wireless convergence is becoming popular as one of the most efficient access network designs that provides quality of service (QoS) guaranteed, uninterrupted, and ubiquitous access to end users. The integration of passive optical networks (PONs) with next-generation wireless access networks is not only a promising integration option but also a cost-effective way of backhauling the next generation wireless access networks. The QoS performance of the PON–wireless converged network can be improved by taking the advantages of the features in both network segments for bandwidth resources management. In this paper, we propose a novel resource allocation mechanism for long term evolution–Gigabit Ethernet PON (LTE–GEPON) converged networks that improves the QoS performance of the converged network. The proposed resource allocation mechanism takes the advantage of the ability to forecast near future packet arrivals in the converged networks. Moreover, it also strategically leverages the inherited features and the frame structures of both the LTE network and GEPON, to manage the available bandwidth resources more efficiently. Using extensive simulations, we show that our proposed resource allocation mechanism improves the delay and jitter performance in the converged network while guarantying the QoS for various next generation broadband services provisioned for both wireless and wired end users. Moreover, we also analyze the dependency between different parameters and the performance of our proposed resource allocations scheme.     

A distributed-request-based CDMA CAC for DiffServ multimedia services in wireless cellular mobile networks

In this paper, a distributed-request-based CDMA DiffServ (differentiated service) call admission control (CAC) scheme is proposed to provide various multimedia services seamlessly in wireless mobile Internet. Conventional CDMA CAC schemes cannot fully support DiffServ QoS (Quality of Service) and seamless handoff due to lack of consideration on service priority and seamless mobility. Therefore, in order to achieve QoS guarantee for each service class, seamless fast-handoff, and high utilization of the scarce wireless resource, we define a code assignment policy and an adaptive access permission scheme taking each user’s service priority and mobility into consideration. For that purpose, in the proposed scheme, the DQRUMA/CDMA is combined with the new code assignment scheme and the adaptive access permission probability (APP). Numerical examples show that the forced termination ratio of handoff calls is guaranteed to be much less than the blocking ratio of new calls for a seamless fast-handoff while proposed scheme provides QoS guarantee for each service class efficiently.     

An efficient joint channel assignment and QoS routing protocol for IEEE 802.11 multi-radio multi-channel wireless mesh networks

With the emerging of video, voice over IP (VoIP) and other real-time multimedia services, more and more people pay attention to quality of service (QoS) issues in terms of the bandwidth, delay and jitter, etc. As one effective way of broadband wireless access, it has become imperative for wireless mesh networks (WMNs) to provide QoS guarantee. Existing works mostly modify QoS architecture dedicated for ad hoc or sensor networks, and focus on single radio and single channel case. Meanwhile, they study the QoS routing or MAC protocol from view of isolated layer. In this paper, we propose a novel cross-layer QoS-aware routing protocol on OLSR (CLQ-OLSR) to support real-time multimedia communication by efficiently exploiting multi-radio and multi-channel method. By constructing multi-layer virtual logical mapping over physical topology, we implement two sets of routing mechanisms, physical modified OLSR protocol (M-OLSR) and logical routing, to accommodate network traffic. The proposed CLQ-OLSR is based on a distributed bandwidth estimation scheme, implemented at each node for estimating the available bandwidth on each associated channel. By piggybacking the bandwidth information in HELLO and topology control (TC) messages, each node disseminates information of topology and available bandwidth to other nodes in the whole network in an efficient way. From topology and bandwidth information, the optimized path can be identified. Finally, we conduct extensive simulation to verify the performance of CLQ-OLSR in different scenarios on QualNet platform. The results demonstrate that our proposed CLQ-OLSR outperforms single radio OLSR, multi-radio OLSR and OLSR with differentiated services (DiffServ) in terms of network aggregate throughput, end-to-end packet delivery ratio, delay and delay jitter with reasonable message overheads and hardware costs. In particular, the network aggregate throughput for CLQ-OLSR can almost be improved by 300% compared with the single radio case.     

Virtual Strategy QoS routing in satellite networks

Satellite network users want to unify different satellites to enhance the quality-of-service (QoS) stability of the satellite networks and select feasible paths through different networks to feed different applications. Unfortunately, the state of affairs is that different applications need to use several different application programming interfaces and to design different protocols on how and when to use a specific network. This is troublesome and error-prone as the application programming interfaces vary a lot. In this paper, we design a Virtual Strategy in satellite network based on which a QoS routing service scheme is then proposed. We analyze why applications should use and benefit from Virtual Strategy. This Virtual Strategy is a middleware solution that enables seamless usage of services from different satellite network parts. And then, the supporting QoS routing solution enables the committed QoS services over Virtual Strategy. Finally, we provide a comparison between the previous satellite networks and our work. The simulation results show that our Virtual Strategy QoS routing scheme demonstrates dominated performances under complex architecture.     

DiffServ网络中接纳控制方法的研究

深入分析了DiffServ网络中接纳控制方法的缺点,提出了一种新的接纳控制方法.该方法将边界和内部接纳控制分开进行.边界接纳控制时,采用边界区分服务策略,根据流对QoS不同要求,将流分为两类区别对待,不但提高了网络资源利用率,而且保证了流的服务质量;内部接纳挖制时,采用了基于路径的方法,大大提高了网络接纳控制的效率.     

A traffic-class burst-polling based delta DBA scheme for QoS in distributed EPONs

Ethernet passive optical network (EPON) preserves the merits of traditional Ethernet network while reducing complexities and improving quality of service (QoS). In this paper, a traffic-class burst-polling based delta dynamic bandwidth allocation (TCBP-DDBA) scheme is presented to provide better QoS to expedited forwarding packet and maximize channel utilization service to assure forwarding and best effort packets. The network resources are efficiently utilized and adaptively allocated to the three traffic classes by guaranteeing the requested QoS. Simulation results using OPNET show that the TCBP-DDBA scheme performs well in comparison to the conventional allocation scheme for a set of given parameters such as: packet delay, queue size, packet delay variation and channel utilization. This work considers system-wide DBA development in contrast to unit-based approach. It is concluded that the algorithm can be used for many types of EPON-based practical distributed networks.     

SLA-based QoS pricing in DiffServ networks

The availability of high-speed transmission media and networking equipment in contemporary networks, as well as the evolution of quality-demanding applications has focused research interest on the provision of advanced qualitative services in addition to the traditional best-effort model of the Internet. A number of alternatives for service differentiation and QoS provisioning have been proposed and standardized, but in the case of backbone, transport networks the DiffServ architecture has prevailed, due to its scalability and deployment feasibility. The provisioning of services according to the DiffServ framework has in turn raised the requirements for interdependent, controlled resource allocation and service pricing, with particular needs for pricing mechanisms that preserve the potential and flexibility of DiffServ. At the same time, such mechanisms should reflect resource usage, allocate resources efficiently, reimburse costs or maximize service provision profits and lead customers to requesting services that will maximize their revenue. In this work, after reviewing related research, the principles that a pricing scheme for DiffServ-based services should follow are presented, stressing the differences form traditional Internet pricing. Based on these principles, an analytical approach to pricing a particular class of DiffServ-based services and a methodology for applying this approach in a real network are proposed and evaluated.     

New MPLS network management techniques based on adaptive learning

The combined use of the differentiated services (DiffServ) and multiprotocol label switching (MPLS) technologies is envisioned to provide guaranteed quality of service (QoS) for multimedia traffic in IP networks, while effectively using network resources. These networks need to be managed adaptively to cope with the changing network conditions and provide satisfactory QoS. An efficient strategy is to map the traffic from different DiffServ classes of service on separate label switched paths (LSPs), which leads to distinct layers of MPLS networks corresponding to each DiffServ class. In this paper, three aspects of the management of such a layered MPLS network are discussed. In particular, an optimal technique for the setup of LSPs, capacity allocation of the LSPs and LSP routing are presented. The presented techniques are based on measurement of the network state to adapt the network configuration to changing traffic conditions.     

OpenIPTV: a comprehensive SDN-based IPTV service framework

IPTV is an emerging TV content delivery service that should guarantee Quality of Service (QoS) to deliver television contents over IP for their customers. However, providing such QoS regarding service level agreements (SLA) requires frequent service monitoring and adaptive configuration mechanisms. Nowadays, Software Defined Networks (SDNs) provide capabilities to deploy and manage networks dynamically and can maintain QoS. In this paper, a novel IPTV service framework (OpenIPTV) is proposed, which utilizes SDN as an underlying technology for providing QoS for IPTV customers in a shared backbone network. OpenIPTV is implemented in a well-known OpenDayLight controller and strictly followed a modular design for the sake of efficiency. OpenIPTV comprises all service requirements such as resource monitoring, channel changing, multicast group managing and dynamic QoS multicast traffic engineering. The performance of OpenIPTV is evaluated under different scenarios and experimental results confirmed the effectiveness of the proposed framework in terms of QoS metrics. Furthermore, experimental results show that OpenIPTV is a feasible and practical solution to deliver IPTV services with high level of QoS over SDN.     

Big Data Based Self-optimization Networking: A Novel Approach Beyond Cognition

It is essential to satisfy class-specific QoS constraints to provide broadband services for new generation wireless networks. A self-optimization technique is introduced as the only viable solution for controlling and managing this type of huge data networks. This technique allows control of resources and key performance indicators without human intervention, based solely on the network intelligence. The present study proposes a big data based self optimization networking (BD-SON) model for wireless networks in which the KPI parameters affecting the QoS are assumed to be controlled through a multidimensional decision-making process. Also, Resource Management Center (RMC) was used to allocate the required resources to each part of the network based on made decision in SON engine, which can satisfy QoS constraints of a multicast session in which satisfying interference constraints is the main challenge. A load-balanced gradient power allocation (L-GPA) scheme was also applied for the QoS-aware multicast model to accommodate the effect of transmission power level based on link capacity requirements. Experimental results confirm that the proposed power allocation techniques considerably increase the chances of finding an optimal solution. Also, results confirm that proposed model achieves significant gain in terms of quality of service and capacity along with low complexity and load balancing optimality in the network.     

基于IPv6网络的多媒体传输QoS研究

随着IP网络的发展,越来越多的服务被提供,如视频点播、VoIP、视频会议等。但是,IP网络只能够提供尽力而为的服务,而不能提供有效的QoS保证,尤其对于多媒体应用。借鉴IPv6支持QoS的新特性,结合RSVP协议并将综合服务和区分服务进行整合,在此基础上基于IPv6网络实现了一个保证多媒体通讯QoS的技术方案。     

Topology-aware wavelength partitioning for DWDM OBS networks: A novel approach for absolute QoS provisioning

Optical Burst Switching (OBS) is a promising switching technology for the next generation all-optical networks. An OBS network without wavelength converters and fiber delay lines can be implemented simply and cost-effectively using the existing technology. However, this kind of networks suffers from a relatively high burst loss probability at the OBS core nodes. To overcome this issue and consolidate OBS networks with QoS provisioning capabilities, we propose a wavelength partitioning approach, called Optimization-based Topology-aware Wavelength Partitioning approach (OTWP). OTWP formulates the wavelength partitioning problem, based on the topology of the network, as an Integer Linear Programming (ILP) model and uses a tabu search algorithm (TS) to resolve large instances efficiently. We use OTWP to develop an absolute QoS differentiation scheme, called Absolute Fair Quality of service Differentiation scheme (AFQD). AFQD is the first absolute QoS provisioning scheme that guarantees loss-free transmission for high priority traffic, inside the OBS network, regardless of its topology. Also, we use OTWP to develop a wavelength assignment scheme, called Best Effort Traffic Wavelength Assignment scheme (BETWA). BETWA aims to reduce loss probability for best effort traffic. To make AFQD adaptive to non-uniform traffic, we develop a wavelength borrowing protocol, called Wavelength Borrowing Protocol (WBP). Numerical results show the effectiveness of the proposed tabu search algorithm to resolve large instances of the partitioning problem. Also, simulation results, using ns-2, show that: (a) AFQD provides an excellent quality of service differentiation; (b) BETWA substantially decreases the loss probability of best effort traffic to a remarkably low level for the OBS network under study; and (c) WBP makes AFQD adaptive to non-uniform traffic by reducing efficiently blocking probability for high priority traffic.     

Bandwidth Aggregation-Aware Dynamic QoS Negotiation for Real-Time Video Streaming in Next-Generation Wireless Networks

In next generation wireless networks, Internet service providers (ISPs) are expected to offer services through several wireless technologies (e.g., WLAN, 3G, WiFi, and WiMAX). Thus, mobile computers equipped with multiple interfaces will be able to maintain simultaneous connections with different networks and increase their data communication rates by aggregating the bandwidth available at these networks. To guarantee quality-of-service (QoS) for these applications, this paper proposes a dynamic QoS negotiation scheme that allows users to dynamically negotiate the service levels required for their traffic and to reach them through one or more wireless interfaces. Such bandwidth aggregation (BAG) scheme implies transmission of data belonging to a single application via multiple paths with different characteristics, which may result in an out-of-order delivery of data packets to the receiver and introduce additional delays for packets reordering. The proposed QoS negotiation system aims to ensure the continuity of QoS perceived by mobile users while they are on the move between different access points, and also, a fair use of the network resources. The performance of the proposed dynamic QoS negotiation system is investigated and compared against other schemes. The obtained results demonstrate the outstanding performance of the proposed scheme as it enhances the scalability of the system and minimizes the reordering delay and the associated packet loss rate.