An Optimization-Based Approach for QoS Routing in High-Bandwidth Networks

In this paper, we propose an optimization-based approach for Quality of Service (QoS) routing in high-bandwidth networks. We view a network that employs QoS routing as an entity that distributively optimizes some global utility function. By solving the optimization problem, the network is driven to an efficient operating point. In earlier work, it has been shown that when the capacity of the network is large, this optimization takes on a simple form, and once the solution to this optimization problem is found, simple proportional QoS routing schemes will suffice. However, this optimization problem requires global information. We develop a distributed and adaptive algorithm that can efficiently solve the optimization online. Compared with existing QoS routing schemes, the proposed optimization-based approach has the following advantages: 1) the computation and communication overhead can be greatly reduced without sacrificing performance; 2) the operating characteristics of the network can be analytically studied; and 3) the desired operating point can be tuned by choosing appropriate utility functions     

Adaptive Online Sensor Clustering and Routing Algorithms for QoS Provisioning and Energy Efficiency

Due to the limited energy supply, energy efficiency is the most important issue for wireless sensor networks. In addition, next generation networks are also expected to support QoS sensitive data services. In this paper, a new online sensor network management scheme is developed for energy efficiency and QoS provisioning. To satisfy these conflicting requirements, the proposed scheme consists of clustering and routing algorithms. Without global network information, the online control paradigm is realized in a distributed way. Therefore, the principle contributions of these algorithms are its scalability and responsiveness to current network situations. Simulation results indicate the superior performance of the proposed schemes, while other schemes cannot offer such an attractive performance balance.     

QoS-driven multicast routing in sparse-splitting optical networks

This paper investigates the quality-of-service (QoS)-driven multicast routing problem in a sparse-splitting optical network. The main objective is to minimize the total cost of wavelength channels utilized by the light-tree while satisfying required QoS parameters. In this paper, both the optical-layer constraints (e.g., optical signal power) and application-layer requirements (e.g., end-to-end delay and inter-destination delay variation) are considered as the QoS parameters. First, integer linear programming (ILP) formulations to solve the optimal multicast routing problem with the given QoS parameters are presented. Solving the ILP formulations for large-scale networks can easily overwhelm the capabilities of state-of-the-art computing facilities, and hence, a heuristic algorithm is proposed to construct a feasible light-tree that satisfies the required QoS parameters in large-scale networks. Simulation results demonstrate the performance of the proposed heuristic algorithm in terms of the cost of utilized wavelength channels.     

基于蚁群算法的自适应QoS路由优化

Internet网络规模的迅速增长和网络技术的不断完善，使得如何在满足QoS（quality of service）要求下进行路由选择成为路由算法研究的重要方向。提出了一种多约束条件下的自适应蚁群算法，该算法基于目标函数的信息素分配策略来自适应地调整蚂蚁的搜索行为，使多约束QoS路由优化问题得到了很好的解决。     

A localized adaptive proportioning approach to QoS routing

In QoS routing, paths for flows are selected based on knowledge of resource availability at network nodes and the QoS requirements of flows. Several QoS routing schemes have been proposed that differ in the way they gather information about the network state and select paths based on this information. We broadly categorize these schemes into best path routing and proportional routing. The best path routing schemes gather global network state information and always select the best path for an incoming I-low,based on this global view. It has been shown that best path routing schemes require frequent exchange of network state, imposing both communication overhead on the network and processing overheads on the core routers. On the other hand, proportional routing schemes proportion incoming flows among a set of candidate paths. We have shown that it is possible to compute near-optimal proportions using only locally collected information. Furthermore, a few good candidate paths can be selected using infrequently exchanged global information and thus with minimal communication overhead. We describe these schemes in detail and demonstrate that proportional routing schemes can achieve higher throughput with lower overhead than best path routing schemes     

Study on the performance of the A*Prune QoS routing algorithm for intelligent optical networks and its improvements

1 Introduction In the past few years, many routing algorithms for compu- ting constrained paths have been proposed in the networking community. In the earlier days, research study has been concentrated on a single additive constraint, especially the delay…     

Cross-Layer Design for QoS in Wireless Mesh Networks

Cross-layer design for quality of service (QoS) in wireless mesh networks (WMNs) has attracted much research interest recently. Such networks are expected to support various types of applications with different and multiple QoS and grade-of-service (GoS) requirements. In order to achieve this, several key technologies spanning all layers, from physical up to network layer, have to be exploited and novel algorithms for harmonic and efficient layer interaction must be designed. Unfortunately most of the existing works on cross-layer design focus on the interaction of up to two layers while the GoS concept in WMNs has been overlooked. In this paper, we propose a unified framework that exploits the physical channel properties and multi-user diversity gain of WMNs and by performing intelligent route selection and connection admission control provides both QoS and GoS to a variety of underlying applications. Extensive simulation results show that our proposed framework can successfully satisfy multiple QoS requirements while it achieves higher network throughput and lower outage as compared to other scheduling, routing and admission control schemes.     

一种智能ABC支持型QoS切换决策机制

本文提出了一种总最佳连接ABC(Always Best Connected)支持型服务质量QoS(Quality of Service)切换决策机制,引入模糊数学和微观经济学等相关知识,刻画应用类型、QoS需求、接入网络和移动终端,综合考虑应用QoS需求、用户愿付费用、用户对接入网络编码制式偏好、用户对接入网络供应商偏...     

QoS-aware routing in emerging heterogeneous wireless networks[Quality-of-Service-Based Routing Algorithms for Heterogeneous Networks]

The integration of different kinds of wireless mobile networks, or heterogeneous wireless networks (HWNs), is emerging. However, a systematic discussion with regard to the special requirements and the complexity of QoS-aware routing in such networks and how QoS is blended with routing is still largely missing. This article aims to cast some light on these aspects. Based on an analysis of the basic architecture of an emerging heterogeneous wireless network and its new requirements on QoS-aware routing, a policy-based QoS supporting system infrastructure and a QoS-aware routing algorithm called QRA are presented in this article. The presentation is specifically given to these issues and components that are unique to HWNs and its QoS routing. The evaluation results show the impact of different network parameters on the performance of QoS-aware routing in HWNs     

A scalable approach to the partition of QoS requirements in unicast and multicast

Supporting quality of service (QoS) in large-scale broadband networks poses major challenges, due to the intrinsic complexity of the corresponding resource allocation problems. An important problem in this context is how to partition QoS requirements along a selected topology (path for unicast and tree for multicast). As networks grow in size, the scalability of the solution becomes increasingly important. This calls for efficient algorithms, whose computational complexity is less dependent on the network size. In addition, recently proposed precomputation-based methods can be employed to facilitate scalability by significantly reducing the time needed for handling incoming requests. We present a novel solution technique to the QoS partition problem(s), based on a "divide-and-conquer" scheme. As opposed to previous solutions, our technique considerably reduces the computational complexity in terms of dependence on network size; moreover, it enables the development of precomputation schemes. Hence, our technique provides a scalable approach to the QoS partition problem, for both unicast and multicast. In addition, our algorithms readily generalize to support QoS routing in typical settings of large-scale networks.     

A hierarchical multilayer QoS routing system with dynamic SLAmanagement

This paper proposes a hierarchical multilayer QoS routing system with dynamic SLA management for large-scale IP networks. Previously, the promising approach to provide QoS in large-scale IP networks using a mixture of DiffServ-based QoS management and MPLS-based traffic engineering has been actively discussed. However, the introduction of QoS exacerbates the already existing scalability problems of the standard IP routing protocols. In order to address this issue, we propose a new scalable routing framework based on hierarchical QoS-aware path computation. We augment the existing OSPF and CR-LDP protocols to support hierarchical QoS routing, QoS aggregation, and QoS reservation in our MPLS-DiffServ-based hierarchical routing network. In order to provide additional flexibility and cost-efficiency, we augment the network with a policy server which is capable of dynamically handling SLAs between the networks and providing load balancing management within the network. We implement a prototype of the proposed framework and study its performance with a virtual network simulator and specially designed QoS routing algorithm simulator. In our simulations, we evaluate both the implementation complexity and algorithms performance; the results demonstrate the efficiency of the framework and its advantages over the existing proposals     

IP/ MPLS over WDM网中考虑QoS的VPN业务设计

本文研究了在IP／MPLS over WDM网络中支持不同QoS要求的VPN业务的逻辑拓扑设计问题。对于给定的网络物理拓扑和业务需求矩阵，本文提出，基于不同时延要求的VPN业务逻辑拓扑设计可以运用两种方法加以解决。一为基于迭代的线性规划方法，适合于规模较小的网络。另一个为启发式算法，可运用于网络规模较大的环境。对比仿真结果表明，启发式算法不但较好地解决了不同QoS要求的VPN业务的选路和波长分配问题，还较好地降低了链路的最大负载。     

Bandwidth-satisfied multicast trees in large-scale ad-hoc networks

The purpose of this paper is to construct bandwidth-satisfied multicast trees for QoS applications in large-scale ad-hoc networks (MANETs). Recent routing protocols and multicast protocols in large-scale MANETs adopt two-tier infrastructures to avoid the inefficiency of the flooding. Hosts with a maximal number of neighbors are often chosen as backbone hosts (BHs) to forward packets. Most likely, these BHs will be traffic concentrations/bottlenecks of the network. In addition, since host mobility is not taken into consideration in BH selection, these two-tier schemes will suffer from more lost packets if highly mobile hosts are selected as BHs. In this paper, a new multicast protocol is proposed for partitioning large-scale MANET into two-tier infrastructures. In the proposed two-tier multicast protocol, hosts with fewer hops and longer remaining connection time to the other hosts will be selected as BHs. The objective is not only to obtain short and stable multicast routes, but also to construct a stable two-tier infrastructure with fewer lost packets. Further, previous MANET quality-of-service (QoS) routing/multicasting protocols determined bandwidth-satisfied routes for QoS applications. Some are implemented as a probing scheme, but the scheme is inefficient due to high overhead and slow response. On the contrary, the others are implemented by taking advantage of routing and link information to reduce the inefficiency. However, the latter scheme suffers from two bandwidth-violation problems. In this paper, a novel algorithm is proposed to avoid the two problems, and it is integrated with the proposed two-tier multicast protocol to construct bandwidth-satisfied multicast trees for QoS applications in large-scale MANETs. The proposed algorithm aims to achieve better network performance by minimizing the number of forwarders in a tree.     

QoS-aware routing based on bandwidth estimation for mobile ad hoc networks

Routing protocols for mobile ad hoc networks (MANETs) have been explored extensively in recent years. Much of this work is targeted at finding a feasible route from a source to a destination without considering current network traffic or application requirements. Therefore, the network may easily become overloaded with too much traffic and the application has no way to improve its performance under a given network traffic condition. While this may be acceptable for data transfer, many real-time applications require quality-of-service (QoS) support from the network. We believe that such QoS support can be achieved by either finding a route to satisfy the application requirements or offering network feedback to the application when the requirements cannot be met. We propose a QoS-aware routing protocol that incorporates an admission control scheme and a feedback scheme to meet the QoS requirements of real-time applications. The novel part of this QoS-aware routing protocol is the use of the approximate bandwidth estimation to react to network traffic. Our approach implements these schemes by using two bandwidth estimation methods to find the residual bandwidth available at each node to support new streams. We simulate our QoS-aware routing protocol for nodes running the IEEE 802.11 medium access control. Results of our experiments show that the packet delivery ratio increases greatly, and packet delay and energy dissipation decrease significantly, while the overall end-to-end throughput is not impacted, compared with routing protocols that do not provide QoS support.     

Hybrid QoS based routing protocol for inter and intra wireless mesh infrastructure communications

Quality of service (QoS) in wireless mesh networks is an active area of research, which is driven by the increasing demand for real-time and multimedia applications, such as Voice over IP and Video on Demand. In this paper, we propose a novel QoS based routing protocol for wireless mesh infrastructure, called Hybrid QoS Mesh Routing (HQMR). It is composed of two QoS based routing sub-protocols: a reactive multi-metric routing protocol for intra-infrastructure communications and a proactive multi-tree based routing protocol for communications with external networks. The proposed routing protocol enables forwarding real-time and streaming applications with QoS guarantee in a mesh wireless environment, by assigning a specific routing path for each defined service class. To this end, three different QoS service classes are defined, depending on the applications requirements. We analyze in this paper the simulation results of different scenarios conducted on the network simulator ns-3 to demonstrate the effectiveness of the HQMR protocol and to compare it to other routing protocols while forwarding real-time applications with QoS guarantee.     

An Ant-based Multipath Routing Algorithm for QoS Aware Mobile Ad-hoc Networks

In the wireless ad-hoc network management, Quality of Service (QoS) is an important issue. Along with the QoS ensuring, another desirable property is the network reliability. In data communications, multi-path routing strategy can cope with the problem of traffic overloads while balancing the network resource consumption. In this paper, we propose a new multipath routing algorithm for QoS-sensitive multimedia services. Based on the ant colony optimization technique, the proposed algorithm can establish effective multi-paths to enhance the network reliability. According to the load balancing strategy, data packets are adaptively distributed through the established paths while maintaining an acceptable level of QoS requirement. The most important feature of the proposed approach is its adaptability to current traffic conditions. Simulation results indicate the superior performance of the proposed algorithm, while other schemes cannot offer such an attractive performance balance.     

QoS aware traffic grooming and integrated routing on IP over WDM networks

In this article, we consider traffic grooming and integrated routing in IP over WDM networks. The challenges of this problem come from jointly considering traffic grooming, IP routing, and lightpath routing and wavelength assignment (RWA). Due to the high bandwidth of optical fiber, there exists a mismatch between the capacity needed by an IP flow and that provided by a single lightpath. Traffic grooming is therefore used to increase the network utilization by aggregating multiple IP flows in a single lightpath. However, traffic grooming incurs additional delays that might violate Quality-of-Service (QoS) requirements of IP users. In this work, the tradeoff between traffic grooming and IP QoS routing is well-formulated as a mixed integer and linear optimization problem, in which the revenue from successfully provisioning IP paths is to be maximized. Problem constraints include IP QoS, routing, optical RWA, and the WDM network capacity. We propose a novel Lagrangean relaxation (LGR) algorithm to perform constraint relaxation and derive a set of subproblems. The Lagrangean multipliers are used in the proposed algorithm to obtain a solution in consideration of grooming advantage and resource constraints simultaneously. Through numerical experiments and comparisons between the proposed algorithm and a two-phase approach, LGR outperforms the two-phase approach under all experimental cases. In particular, the improvement ratio becomes even more significant when the ratio of IP flow to the wavelength capacity is smaller.     

An ACO and position information based intelligent QoS routing mechanism in MANET

Quality of service (QoS) routing technology, which can find the available route, is an important way to realize the end-to-end QoS provisioning for networks. Intelligent routing discovery, establishment and maintenance, which take use of ant colony algorithm, have been widely researched in the past years. But the ant colony algorithm has two obvious shortcomings, which are low convergence rate and algorithm stagnation in local optimum. As the topology of mobile ad hoc network (MANET) is always changing, the information of network status is hard to collect in time. So the enhancement of the convergence rate of the QoS routing algorithm is quite important in MANETs. Based on the AntHocNet algorithm previously designed for ad hoc networks, this paper proposes a position-based intelligent QoS routing algorithm. The position constraints are added in the procedures of tabu list forming and pheromone updating. Compared with AntHocNet, the proposed mechanism can greatly reduce the convergence rate in the premises of searching an available path with QoS guarantee according to the simulation results.     

面向确定性网络的按需智能路由技术

确定性网络需要保证不同应用在时延、丢包率、抖动、吞吐量和可靠性等方面的确定性传输需求。针对应用的差异化、确定性的网络传输需求,提出了一种面向确定性网络的按需智能路由学习框架 OdR,在OdR框架下提出一种基于深度强化学习的按需智能路由算法OdR-TD3,OdR-TD3算法可以根据应用流量的确定性QoS需求生成路由策略,以满足确定性网络应用的需求。通过网络仿真实验评估,在确定性应用的QoS需求达成率上,OdR-TD3算法相较DV算法和SPF算法,具有显著的优势。     

Power Savings in Packet Networks via Optimised Routing

This paper examines the use of a gradient-based algorithm for Quality of Service (QoS) and power minimisation in wired networks to result on reduced energy consumption. Two distinct schemes, conventional shortest-path routing and an autonomic algorithm energy aware routing algorithm (EARP) are investigated as the starting point for the gradient algorithm. Comparisons are conducted using the same network test-bed and identical network traffic under conditions where routers and link drivers are always kept on so as to meet the needs for network reliability in the presence of possible failures and unexpected overload. Since splitting traffic flows can increase jitter and the arrival of packets which are out of sequence, we also do not allow the same packet flow to be conveyed over multiple paths. In the experiments that we have conducted we observe that power consumed with the gradient-optimiser that is proposed in this paper is a few percent to 10% smaller than that consumed using shortest-path routing or EARP. Although the savings are small, they can be very significant for the Internet backbone as a whole over long periods of time, and further power savings may be obtained by judiciously putting to sleep equipment when it is under-utilised.