Frame‐level performance measurement in an ATM test‐bed environment: methodologies and experiences

Performance testing is related to user‐perceived performance of asynchronous transfer mode (ATM) technology. We describe the test methodologies used to measure various frame‐level quality of service metrics, such as throughput and latency. Some practical issues encountered in performance testing in an ATM test‐bed environment are addressed. Copyright © 2004 John Wiley & Sons, Ltd.     

基于LDP的MPLS网络流量统计功能的研究

随着MPLS(Multi-Protocol Label Switch)技术的逐步成熟,其承载的业务越来越丰富,网络流量成为描述网络行为的重要指标之一.主要介绍了分布式设备中基于LDP(Label Distribute Protocol)的MPLS网络流量统计功能的实现,详细阐述了系统模块的交互关系、处理流程以及主要的函数接口与数据结构,最后对该功能进行组网测试.测试结果证明了LSP(Label Switch Path)流量统计功能的有效性,能很好地满足用户、运营商的业务需求.     

一种基于跳数和时延的MPLS自适应流量工程算法

提出了一种基于跳数和时延的MPLS自适应流量工程算法，该算法根据LSP的跳数和时延来进行流量分配，从而减少由传统路由算法而引起的网络拥塞，优化网络资源的利用。仿真结果表明，该算法简单易行，性能良好。     

基于IP/MPLS网络的动态业务流量矩阵测量模型

IP网络动态业务流量矩阵的测量是业务量工程研究中的一个难点,本文提出了一种面向IP/MPLS骨干网络的基于LSP级的动态业务流量矩阵测量模型。该模型能够获取网络边界处对应于每一条LSP的路径转发信息,并根据每一条LSP上的测量结果,计算得知全网的业务流量矩阵。文中证明该测量模型是可行的,并给出了相关的算法及其性能分析。模型的优点是测量只在网络边界处进行而不涉及网络核心,故引起的网络开销较小。另外模型所需的算法复杂度低,仿真结果显示测量模型是有效的。     

Community‐based traffic preservation in telecommunication networks

Large‐scale failures in telecommunication networks have been traditionally mitigated by attempting to preserve global connectivity in the network. However, although communication inside communities may be of high relevance, their preservation is a challenging task. To achieve this, we propose a new concept of community that combines not only the topological information of the network but also the traffic‐level interaction. This new concept is then used to present six novel community‐based strategies that, when working within a limited budget, are able to determine which are the best candidate nodes to protect. The strategies proposed have been tested over four different types of networks and have been compared with other well‐known immunization or protection methods. Results show that community‐based strategies better preserve the inner community traffic with respect to traditional approaches. Furthermore, in some cases, both global and intra‐community traffic preservation is able to be improved. Copyright © 2013 John Wiley & Sons, Ltd.     

MPLS and traffic engineering in IP networks

Rapid growth and increasing requirements for service quality, reliability, and efficiency have made traffic engineering an essential consideration in the design and operation of large public Internet backbone networks. Internet traffic engineering addresses the issue of performance optimization of operational networks. A paramount objective of Internet traffic engineering is to facilitate the transport of IP traffic through a given network in the most efficient, reliable, and expeditious manner possible. Historically, traffic engineering in the Internet has been hampered by the limited functional capabilities of conventional IP technologies. Recent developments in multiprotocol label switching (MPLS) and differentiated services have opened up new possibilities to address some of the limitations of the conventional technologies. This article discusses the applications of MPLS to traffic engineering in IP networks     

一种基于网络最大流的MPLS流量工程动态路由算法

在MPLS技术基础上提出了一种基于网络最大流的有带宽保证的动态路由算法-MBGRA,该算法通过链路对结点对之间的网络最大流的贡献程度以及链路的带宽利用率来定义链路权重,并且链路对将来建立新的标签交换路径的影响一同考虑.     

A performance evaluation of BGP‐based traffic engineering

Many Internet Service Providers tune the configuration of the Border Gateway Protocol on their routers to control their traffic. Content providers often need to control their outgoing traffic while access providers need to control their incoming traffic. We show, by means of measurements and simulations, that controlling the flow of the incoming interdomain traffic is a difficult problem. For this purpose, we first rely on detailed measurements to show the limitations of AS‐Path prepending. Then, we show by using large‐scale simulations that the difficulty of controlling the flow of the incoming traffic lies in the difficulty of predicting which BGP route will be selected by distant Autonomous Systems (ASs). Copyright © 2005 John Wiley & Sons, Ltd.     

一个MPLS流量工程的QoS路由算法

传统Internet中,多媒体流量和实时电子商务应用会引起品质的降低。这可以通过在网络中动态地建立有带宽和延迟保证的路径来解决。讨论了基本算法,如最宽最短路径（WSP）,复杂一些的算法如最小冲突路由（MIRA）或基于剖面的路由。提出了一个新的MPLS网络中的Diff-Serv流的QoS路由算法。这个方法在维持网络效率的同时,有效地传输多媒体流量。     

MPLS网络主动式流量和拥塞控制机制及性能分析

MPLS是具有大带宽一时延迟的网络,用传统的TCP解决MPLS拥塞问题显得十分困难,该文结合MPLS的网络特点,提出了一种适合MPLS网络的主动式流量和拥塞控制机制,在网络边缘节点引入拥塞反馈处理,对实验模型进行了性能仿真分析,实验证明,与传统的TCP协议相比,该机制将流量和拥塞控制从用户端点扩展到MPLS边缘路由器,能够更及时地检测和控制网络拥塞,缩短了控制时延,可以进行较精确的流量调节,实现了提高吞吐量和改善缓冲区利用率的目的。     

A network processor‐based architecture for multi‐gigabit traffic analysis

The wide availability of cheap and effective commodity PC hardware has driven the development of versatile traffic monitoring software such as protocol analyzers, traffic characterizers and intrusion detection systems. Most of them are designed to run on general purpose architectures and are based on the well‐known libpcap API, which has rapidly become a de facto standard. Although many improvements have been applied to packet capturing software, it still suffers from several performance flaws, mainly due to the underlying hardware bottlenecks. To overcome these issues, this paper proposes a system architecture, which combines the high performance of a Network Processor card with the flexibility of software‐based solutions. It allows for removing most part of the hardware limitations exhibited by a purely PC‐based architecture, while preserving the full compliance to any software applications based on libpcap. In addition, the proposed system enables the use of monitoring applications at the wire speed, with the possibility of on‐the‐fly data processing. The system performance has been thoroughly assessed: the results show that it clearly outperforms the previous PC‐based solutions in terms of packet capturing power, while the timestamping accuracy is as good as that achieved by DAG cards. Copyright © 2009 John Wiley & Sons, Ltd.     

面向卫星网络的流量工程路由算法

针对卫星网络链路长时延、拓扑时变等特征,将链路传输时延引入并基于MPLS网络中源-目的节点对已知这一先验知识,提出了一种面向卫星网络的MPLS流量工程路由算法。该算法基于卫星网络时变拓扑模型的卫星拓扑快照,定义链路初始权重为链路剩余带宽、传输时延的综合函数,在为当前节点对建路时考虑其余节点对将来建路的可能需求计算链路的关键度,在此基础上通过链路权重的动态调整及延期选用实现流量工程,从而优化卫星网络的链路利用。实验表明,此算法在请求拒绝数、吞吐量、平均跳数及平均时延等方面性能都有较理想的提升。     

Packet‐level‐based traffic aggregation to optimize NDN content delivery

In recent years, named data networking (NDN) has been accepted as the most popular future paradigm and attracted much attention, of which the routing model contains interest forwarding and content delivery. However, interest forwarding is far from the bottleneck of routing optimization; instead, the study on content delivery can greatly promote routing performance. Although many proposals on content delivery have been investigated, they have not considered packet‐level caching and deep traffic aggregation, which goes against the performance optimization of content delivery. In this paper, we propose a packet‐level‐based traffic aggregation (PLTA) scheme to optimize NDN content delivery. At first, the packet format is devised, and data plane development kit (DPDK) is used to ensure same size for each packet. Then, the whole delivery scheme with traffic aggregation consideration is presented. The simulation is driven by the real YouTube dataset over Deltacom, NSFNET, and CERNET topologies, and the experimental results demonstrate that the proposed PLTA has better delivery performance than three baselines in terms of cache hit ratio, delivery delay, network load, and energy efficiency.     

Fine‐grained traffic classification based on functional separation

Current efforts to classify Internet traffic highlight accuracy. Previous studies have focused on the detection of major applications such as P2P and streaming applications. However, these applications can generate various types of traffic which are often considered as minor and ignorant traffic portions. As network applications become more complex, the price paid for not concentrating on minor traffic classes is in reduction of accuracy and completeness. In this context, we propose a fine‐grained traffic classification scheme and its detailed method, called functional separation. Our proposal can detect, according to functionalities, different types of traffic generated by a single application and should increase completeness by reducing the amount of undetected traffic. We verify our method with real‐world traffic. Our performance comparison against existing DPI‐based classification frameworks shows that the fine‐grained classification scheme achieves consistently higher accuracyand completeness. Copyright © 2013 John Wiley & Sons, Ltd.     

Integrated load‐based power saving for real‐time and nonreal‐time traffic in LTE‐TDD

Long‐Term Evolution (LTE) is a 4G wireless broadband technology developed by the Third Generation Partnership Project. Two duplex modes, namely, frequency division duplex and time division duplex (TDD), are defined in LTE for transmission in both downlink and uplink directions simultaneously. Power saving mechanisms for LTE‐frequency division duplex were proposed in the authors' previous work. Applicability of the previously proposed mechanisms to LTE‐TDD is investigated in this paper, and the idea of “virtual time” associated with the mapping mechanism from the virtual time domain to the actual time domain for different TDD configurations is proposed. With the help of the mapping mechanism, 3 revised power saving schemes are proposed to support real‐time user equipments and nonreal‐time user equipments in LTE‐TDD. Simulation study demonstrates the effectiveness of the mapping mechanism as well as the benefit of the proposed schemes in power saving efficiency and real‐time support in comparing with the standard‐based mechanism.     

Hopfield neural‐network‐based dynamic resource allocation scheme for non‐real‐time traffic in wireless networks

Dynamic resource allocation (DRA) plays a fundamental role in current and future wireless networks, including 3G systems. In this paper, a scheduling DRA scheme for non‐real‐time (NRT) packet services in wireless system is proposed based on the use of Hopfield neural networks (HNN). The scheme exploits the fast response time of HNN for solving NP optimization problems and has been particularized for the downlink transmission in a UMTS system, although it could be easily extended to any other radio access technology. The new DRA scheme follows a delay‐centric approach, since it maximizes the overall system resource utilization while minimizing the packet delay. Simulation results confirm that the proposed HNN‐based DRA scheme is effective in supporting different types of NRT services, while achieving efficient utilization of radio resources. Copyright © 2008 John Wiley & Sons, Ltd.     

Flow‐Based Admission Control Algorithm in the DiffServ‐Aware ATM‐Based MPLS Network

This paper proposes a flow‐based admission control algorithm through an Asynchronous Transfer Mode (ATM) based Multi‐Protocol Label Switching (MPLS) network for multiple service class environments of Integrated Service (IntServ) and Differentiated Service (DiffServ). We propose the Integrated Packet Scheduler to accommodate IntServ and Best Effort traffic through the DiffServ‐aware MPLS core network. The numerical results of the proposed algorithm achieve reliable delay‐bounded Quality of Service (QoS) performance and reduce the blocking probability of high priority service in the DiffServ model. We show the performance behaviors of IntServ traffic negotiated by end users when their packets are delivered through the DiffServ‐aware MPLS core network. We also show that ATM shortcut connections are well tuned with guaranteed QoS service. We validate the proposed method by numerical analysis of its performance in such areas as throughput, end‐to‐end delay and path utilization.     

QoS‐based radio network dimensioning for LTE networks with heavy real‐time traffic

Applications of video streaming and real‐time gaming, which generate large amounts of real‐time traffic in the network, are expected to gain considerable popularity in Long Term Evolution networks. Maintaining the QoS such as packet delay, packet loss ratio, median, and cell border throughput requirements in networks dominated by real time traffic, is critical. The existing dimensioning methodology does not consider QoS parameters of real‐time traffic in network dimensioning. Moreover, exhaustive and time‐consuming simulations are normally required to evaluate the performance and QoS of real‐time services. To overcome this problem, we propose an improved radio network dimensioning framework that considers the QoS of real‐time traffic in network dimensioning. In this framework, an analytical model is proposed to evaluate the capacity and performance of real‐time traffic dominant Long Term Evolution networks. The proposed framework provides a fast and accurate means of finding the trade‐off between system load, packet delay, packet loss ratio, required median, and cell border throughput. It also provides network operators with an analytical means for obtaining the minimum number of sites required by jointly considering coverage, capacity and QoS requirements. The accuracy of the proposed model is validated through simulations. Copyright © 2012 John Wiley & Sons, Ltd.     

Characterizing network traffic behaviour using granule‐based association rule mining

Association rule mining is one important technique to characterize the behaviour of network traffic. However, mining association rules from network traffic data still have three obstacles such as efficiency, huge number of results and insufficiency to represent the behaviour of network traffic. Aiming to tackle these issues, this paper presents a granule‐based association rule mining approach, called association hierarchy mining. The proposed approach adopts top‐down rule mining strategy to directly generate interesting rules according to subjectively specified rule template hierarchies, which improves the efficiency of rule generation and subjectively filters user uninterested rules. The approach also proposes to prune a new type of redundant rules defined by this research to reduce the number of rules. Finally, the approach introduces the concept of diversity, aiming to select the interesting rules for better interpreting the behaviour of network traffic. The experiments performed on the MAWI network traffic traces show the efficiency and effectiveness of the proposed approach. Copyright © 2016 John Wiley & Sons, Ltd.