Provisioning for interdomain quality of service: the MESCAL approach

This article presents an architecture for supporting interdomain QoS across the multi-provider global Internet. While most research to date has focused on supporting QoS within a single administrative domain, mature solutions are not yet available for the provision of QoS across multiple domains administered by different organizations. The architecture described in this article encompasses the full set of functions required in the management (service and resource), control and data planes for the provision of end-to-end QoS-based IP connectivity services. We use the concept of QoS classes and show how these can be cascaded using service level specifications (SLSs) agreed between BGP peer domains to construct a defined end-to-end QoS. We illustrate the architecture by describing a typical operational scenario.     

QoS约束的链路故障多备份路径恢复算法

链路故障的恢复,不仅仅是选择一条连通的备份路径问题,还应考虑网络业务故障恢复过程中的QoS需求。针对此问题,该文基于多备份路径策略,构建概率关联故障模型和重路由流量丢弃量优化目标。并基于该优化目标,以业务的QoS需求为约束,建立故障恢复问题的数学模型,提出一种QoS约束的链路故障多备份路径恢复算法。该算法构建单条备份路径时,以最大程度地减少重路由流量丢弃为目标,并采用改进的QoS约束的k最短路径法进行拼接,且给与高优先级链路更多的保护资源。此外还证明了算法的正确性并分析了时间空间复杂度。在NS2环境下的仿真结果表明,该算法显著提升了链路故障恢复率和重路由流量QoS满足率,且QoS约束条件越强,相较于其它算法优势越明显。     

An OAM function to improve the packet loss in MPLS‐TP domains for prioritized QoS‐aware services

The emergence of new kinds of applications and technologies (e.g., data‐intensive applications, server virtualization, and big data technology) has led to a higher utilization of network resources. These services imply increased bandwidth consumption and unexpected congestions, especially in backbones. In this article, a novel proposal is studied with the aim of improving the performance of prioritized forwarding equivalence classes in congested Multiprotocol Label Switching Transport Profile (MPLS‐TP) domains. The congestion impact on those QoS‐aware services that require high reliability and low delay is analyzed. A new policy has been implemented on MPLS‐TP, which is a technology that provides QoS by means of flow differentiation in the Internet backbones. The proposal is known as Gossip‐based local recovery policy and is offered as an operation, administration, and management function to allow local recovery of lost traffic for MPLS‐TP privileged forwarding equivalence classes. In order to fulfill the requirements for implementation on MPLS‐TP, a minimum set of extensions to resource reservation protocol traffic engineering has also been proposed to provide self‐management capable routes. Finally, we have carried out a performance improvement measurement by means of an analytical model and simulations. Copyright © 2014 John Wiley & Sons, Ltd.     

Cross-Layer QoS Enabled SDN-Like Publish/Subscribe Communication Infrastructure for IoT

Publish/subscribe paradigm is often adopted to create the communication infrastructure of the Internet of Things(IoT)for many clients to access enormous real-time sensor data.However,most current publish/subscribe middlewares are based on traditional ossified IP networks,which are difficult to enable Quality of Service(QoS).How to design the next generation publish/subscribe middleware has become an urgent problem.The emerging Software Defined Networking(SDN)provides new opportunities to improve the QoS of publish/subscribe facilities for delivering events in IoT owing to its customized programmability and centralized control.We can encode event topics,priorities and security policies into flow entries of SDN-enabled switches to satisfy personalized QoS needs.In this paper,we propose a cross-layer QoS enabled SDN-like publish/subscribe communication infrastructure,aiming at building an IoT platform to seamlessly connect IoT services with SDN networks and improving the QoS of delivering events.We first present an SDN-like topic-oriented publish/subscribe middleware architecture with a cross-layer QoS control framework.Then we discuss prototype implementation,including topic management,topology maintenance,event routing and policy management.In the end,we use differentiated services and cross-layer access control as cross-layer QoS scenarios to verify the prototype.Experimental results show that our middleware is effective.     

Providing and verifying advanced IP services in hierarchical DiffServ networks‐the case of GEANT

The differentiated services (DiffServ) framework is widely proposed as an efficient method for providing advanced IP services to large‐scale networks, with QoS requirements. However, the provisioning of such services in production networks has proved to be more difficult than initially expected, in defining, setting and verifying appropriate Service Level Agreements (SLAs). GEANT, the Gigabit core pan‐European research network, on a pilot basis introduced ‘Premium IP’ service, offering bounded delay and negligible packet loss to the European National Research & Education Networks (NRENs) that it interconnects. However, large scale provisioning of this new service requires the definition of efficient interaction procedures between administrative domains involved and methods for SLA monitoring. This paper focuses on these issues and presents the experience acquired from the early experiments in GEANT, as an example of hierarchical Gigabit multi‐domain environment, enabled with QoS provisioning to its constituent NRENs. This model scales more efficiently than the common peering Internet Service provider (ISP) commercial paradigm. Finally, we outline other options that promise QoS, such as Layer 2 VPNs in MPLS backbones, with non‐standard (yet) mechanisms. Copyright © 2004 John Wiley & Sons, Ltd.     

An approach to the cooperative management of multitechnologynetworks

This article presents a TMN-compliant X interface, the so-called Xcoop interface, as a fundamental component of an operations system developed to cope with the challenges of multidomain, multitechnology networks. Defined at the network level, between operations systems of different TMN domains, it is intended as a support for the management of broadband connectivity services with end-to-end QoS and scheduling constraints in backbones operated by many network operators. The key feature of the present approach, distinguishing it from other existing Xcoop solutions, is in handling the integrated ATM and SDH technologies, covering both the configuration management and fault management functional areas     

Flexible resource allocation strategies for class-based QoS provisioning in mobile networks

Flexible resource-allocation (FRA) strategies have been proposed in the literature to mitigate the high blocking rate caused in high-speed mobile communication networks when resource aggregation is used to increase the data rate. In this paper, new FRA strategies that cope with scenarios with multiple service types and multiple priorities are proposed. These are called the FRA strategy with differentiated priorities and quality of service (FRAQoS) and the FRA strategy with prioritized levels (FRASPL). The main distinguishing feature of these strategies is their capacity to prioritize some service types over others. FRAQoS prioritizes the quality of service (QoS) of particular service types over others by introducing the concepts of prioritized call degradation and compensation. However, FRAQoS provides a limited ability to prioritize particular service types over the rest because any incoming call, irrespective of its service type and priority, may trigger resource reallocations to service it. The FRASPL overcomes this limitation by introducing a call-admission mechanism that, when necessary, rejects calls originated by low-priority service types. This enhances the protection to high-priority service types. By prioritizing some services over the others, FRASPL can trade off capacity against QoS. FRAQoS represents particular limiting cases of FRASPL. A mathematical model is developed to investigate the performance of FRAQoS and FRASPL. Then, they are compared with other FRA strategies in a scenario with multiple differentiated service types. Results show that the proposed strategies effectively prioritize service types, providing them with better QoS. This makes FRAQoS and FRASPL specially suitable for class-based QoS provisioning in mobile networks.     

Modelling multi‐dimensional QoS: some fundamental constraints

In this paper, we model multi‐dimensional QoS in a unified framework, and study some fundamental constraints from the network and the traffic on realizing multiple QoS goals. Multi‐dimensional QoS requirements are quantitatively represented using a QoS region. Based on the theory of effective bandwidths, the framework connects the throughput, the delay, and the loss rate in a uniform formula. Important traffic and network factors, namely, the burst size and the link speed, are involved. With this framework, it is found that the burst size sets hard limit on the QoS region that can be achieved, and that the matching between the link speed and the node processing power can greatly improve the limit. It is also made clear that while pure load imbalance among links does not affect the QoS region, the heterogeneities of burst size or link speed may severely degrade the QoS performance. Applying the theory to real‐time services in differentiated services architecture, we show it provides a useful tool for QoS prediction and network dimensioning. Copyright © 2004 John Wiley & Sons, Ltd.     

Performance analysis of a traffic engineering solution for multilayer networks based on the GMPLS paradigm

This paper presents an integrated traffic engineering (TE) system for new generation multilayer networks based on the generalized multiprotocol label switching (GMPLS) paradigm, and reports the performance analysis of such a system. The proposed TE system aims at dynamically reacting to traffic changes and, at the same time, fulfilling quality of service (QoS) requirements for different classes of service. The proposed solution consists of a hybrid routing approach and a bandwidth management strategy. The former makes use of both off-line and on-line methods to accommodate traffic requests. The latter, based on an "elastic" use of the bandwidth, allows the handling of different priorities among data flows, possible preemptions, and rerouting. The proposed TE permits the accommodation of the largest amount of traffic, while guaranteeing good performance to mission-critical services. The main building blocks and the operations of the system are reported and the major advantages are discussed. The performance of the proposed system are compared with the ones relating to a reasonable alternative system based on overprovisioning, to highlight its advantages of in terms of traffic volume that can be accommodated for a given network infrastructure.     

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.     

一种应急通信中业务感知的宽带自组网路由协议

随着科技进步,我国在应急通信系统建设上也正高速发展,当前应急通信网络对多媒体业务有着迫切需求,对网络带宽要求更高。而当网络存在多种不同业务时,传统通用的路由协议不再适用,它们大多以最小跳数为路由度量或者是某个单一度量,未能考虑不同业务的服务质量(Quality of Service, QoS)需求,因而无法同时兼顾不同业务流的传输要求。提出了一种应急通信中业务感知的宽带自组网路由策略,对不同类型业务在路由和转发优先级上进行区分。经多次仿真验证,该策略能使网络在满足应急语音业务QoS需求的同时,也能兼顾承载的视频、数据等其他业务的性能。     

Intent‐based service management for heterogeneous software‐defined infrastructure domains

One of the main challenges in delivering end‐to‐end service chains across multiple software‐defined networking (SDN) and network function virtualization (NFV) domains is to achieve unified management and orchestration functions. A very critical aspect is the definition of an open, vendor‐agnostic, and interoperable northbound interface (NBI) that should be as abstract as possible and decoupled from domain‐specific data and control plane technologies. In this paper, we propose a reference architecture and an intent‐based NBI for end‐to‐end service management across multiple technological domains. The general approach is tested in a heterogeneous OpenFlow/Internet‐of‐Things (IoT) SDN test bed, where the proposed solution is applied to a rather complex service provisioning scenario spanning three different technological domains: an IoT infrastructure deployment, a cloud‐based data collection, processing, and publishing platform, and a transport domain over a geographic network interconnecting the IoT domain and the data center hosting the cloud services.     

A two‐phase combined QoS‐based handoff scheme in a wireless ATM network

We describe the QoS‐based rerouting algorithm that is designed to implement a two‐phase inter‐switch handoff scheme for wireless ATM networks. We propose to use path extension for each inter‐switch handoff, and invoke path optimization when the handoff path exceeds the delay constraint or maximum path extension hops constraint. We study three types of path optimization schemes: combined QoS‐based, delay‐based and hop based path rerouting schemes. Copyright © 2001 John Wiley & Sons, Ltd.     

Optimal design of Service Overlay Networks with economic and performance constraints

In the last years, Service Overlay Networks (SONs) have emerged as a promising means to address some of the issues (e.g. end‐to‐end QoS) affecting the current Internet and to favor the development and deployment of new value‐added Internet services. The deployment of an SON is a capital‐intensive investment, since bandwidth with certain QoS guarantees must be purchased from the individual network domains through bilateral Service Level Agreements. Thus, minimizing the economic cost of the logical end‐to‐end service delivery infrastructure is one of the key objectives for the SON provider. When a SON is aimed at end‐to‐end QoS provisioning, its topology must be designed so as to also satisfy the specific requirements of QoS‐sensitive applications. This paper deals with the problem of planning the SON topology in order to take into account both cost and QoS constraints. More specifically, the paper proposes a set of new algorithms for the design of an optimized SON topology, which minimizes the economic cost while simultaneously meeting bandwidth and delay constraints. A performance comparison among such algorithms is finally carried out. Copyright © 2009 John Wiley & Sons, Ltd.     

下一代通信网络中基于策略机制的无线资源管理

下一代无线通信系统是一种异构的网络体系,集成多种无线接入技术（Radio Access Technology,RAT）的同时提供多种窄带和宽带多媒体业务。这样的网络环境需要先进的RRM方法来处理复杂多变的无线信道、网络资源的动态配置及保障不同特征业务的服务质量（QoS）,给无线资源管理（Radio Resource Management,RRM）带来了巨大的技术挑战。本文通过引入对网络进行策略控制的思想,提出了一种基于策略机制的通用方法,致力于解决下一代异构（heterogeneous）网络中的无线资源管理。文中着重讨论了基于策略机制的网络接入控制、切换,以及基于策略机制的QoS管理,给出了各功能模块的工作原理和通信过程的分析与设计。     

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.     

Efficient scheduling algorithms for mixed services in wireless OFDMA system

Orthogonal Frequency Division Multiple Access (OFDMA) is an attracting system for combating the frequency selective fading. It’s widely considered as a promising candidate modulation and access scheme for next generation mobile communication systems. However, the explosive growth of multimedia applications raises higher performance requirements for Radio Resource Management (RRM) in OFDMA system. In particular, limited bandwidth and fierce resource competition impose a challenging issue on the design of packet scheduler. In this paper, we propose two scheduling algorithms applicable to mixed services (i.e., real-time and non-real-time services), that is QoS-oriented Dynamic Threshold Control (DTC) algorithm and fairness-oriented Fairness Aware and QoS Aware (FAQA) algorithm. These two algorithms are both composed of two stages, i.e., initial subcarrier allocation and subcarrier reallocation. For the DTC algorithm, in the stage of initial subcarrier allocation, based on the different metrics to weigh QoS between both services, we design a unique scheduling strategy for each type of service. A dynamic threshold is adopted to help users quickly recover from starvation, so that any one user in system can escape from severely degraded QoS. In the stage of subcarrier reallocation, we will reallocate the surplus subcarriers from the buffer-empty users to the buffer-nonempty users so as to increase spectrum efficiency. For FAQA algorithm, in the stage of initial subcarrier allocation, for the purpose of achieving Proportional Fairness (PF) with lower complexity, we deduce a simple scheduling strategy satisfying PF criterion by means of Greedy algorithm. In the stage of subcarrier reallocation, in order to increase the number of users satisfying QoS requirements, we’ll reallocate the surplus subcarriers from the QoS-satisfied users to the QoS-unsatisfied users. Simulation results demonstrate that, on one hand, the DTC algorithm not only guarantees the quality of both services, but also increases the spectrum efficiency; on the other hand, the FAQA algorithm well maintains the fairness among users, and increases the QoS satisfaction degree at the same time.     

Using P2P overlays to provide QoS in service-oriented wireless networks - [Service-oriented broadband wireless network architecture]

An increasing number of applications require some form of guarantees from the network, in terms of bandwidth or access and transfer delay. This demand for quality of service can be met by means of different mechanisms, depending on the networks being traversed, as well as the degree of integration of the services with the communication infrastructure. Whereas end-to-end QoS provision is still an open problem, several possibilities now exist in local environments. The article investigates the capabilities offered by a P2P overlay for distributed bandwidth management in a controlled ad hoc deployment, to support specific requirements in service-oriented wireless networks. The mechanism proposed allows complementing the core functionalities of the IEEE 802.11e protocol, and enhancing them to handle local mobility and dynamic requests for bandwidth. The performance evaluation is provided in an emulated environment to show the effectiveness of the presented approach.     

An evaluation of the key design criteria to achieve high updaterates in packet classifiers

The increased capacity of networks and nodes might enable us to keep pace with the growing traffic load, but the change of paradigm in IP networks towards a QoS-aware and multimedia-friendly infrastructure creates new bottlenecks in the communication path. An example of such a bottleneck is dynamic packet classification, which is fundamental to supporting any sort of QoS and value-added services. Typically, high update rates in packet classification designs have been sacrificed to achieve better search times or to reduce storage capacity requirements. By carefully analyzing current proposals, we unveil three previously neglected key design criteria for general classifiers to successfully achieve high update rates at wire speed: filter localization, nonstructural dependencies, and dynamic precomputation. We also analyze their impact in current algorithms     

基于QoS的端到端差异化管控策略研究

在目前热点区域资源受限的情况下,本文基于eNode B侧和PCC侧的主要QoS管控能力开展网络差异化管控策略研究,形成无线侧最大聚合比特速率限速管控策略、基于用户的PCC管控策略以及基于业务的PCC管控策略,并在现场环境下完成验证。差异化管控策略能够在容量不足的区域有效保障特定用户/业务感知不受影响或优于普通用户/业务,妥善解决高流量和高负荷带来的整体用户感知问题,且能实现资源投入和经济效益的平衡。