IP骨干网流量的自动化预测

高效、可靠的网络流量预测是网络规划、扩容建设的基础。互联网流量目前缺乏完备的理论模型,行业内大多根据工程实践特点,设计简化可操作的预测模型以满足IP网络规划需求。首先根据中国电信自身IP骨干网流量预测工作的需求及特点,使用时间序列分析的多因子回归模型和函数自适应模型对IP骨干网流量进行分析和预测,基于大量现网实际数据的仿真运算,对比两种模型的特点、优劣和适用场景,提出了一种预测模型选择和参数优化的原则和方法。在此基础上,构建了可以满足百千量级时间序列要求的自动化流量预测系统,极大简化并提升了流量预测工作的效率。最后,展望了未来IP流量预测工作的延展方向和关注重点。     

Standardized active measurements on a tier 1 IP backbone

Synthetic or active measurements are often used to characterize IP performance; however, it is rare to find them used to resolve problems in an operational setting. We show that the active monitoring system in the AT&T IP backbone provide's a comprehensive view of network performance that is complementary to traditional element level monitoring, making it an integral part of network management. This paper discusses the design and implementation of these active measurements in the network. We continuously monitor "path-level" performance metrics such as round-trip delay, loss, jitter, and reordering events to proactively detect impairments. Our system relies on the promotion of key metrics to the operational displays, while maintaining a rich set of statistics for analyzing rare and unforeseen events. This timely information enables us to react,quickly to performance degradation, avoiding any sustained effect on customer applications. The results also help us understand the network's ability to support time-sensitive application performance. Selected "interesting" events observed are presented, including detection of degradation caused by low-level bit errors on a physical link, detection of route changes on the network and their impact on real-time applications, and finally detection of reordering caused by forwarding loops.     

A flow-based approach to modeling ADSL traffic on an IP backbone link

Measurements from an Internet backbone link carryingtcp traffic towards differentadsl areas are analyzed in this paper. For traffic analysis, we adopt a flow-based approach and the popular mice/elephants dichotomy. The originality of the experimental data reported in this paper, when compared with previous measurements from very high speed backbone links, is that commercial traffic comprises a significant part due to peer-to-peer applications. This kind of traffic exhibits some remarkable properties in terms of mice, elephants and bit rates, which are thoroughly described in this paper. Global traffic is actually decomposed into several flow components on the basis of the mice/elephants dichotomy. Mice due p2p protocols and mice due to classical Internet applications such ashttp, ftp, etc. are analyzed separately. It turns out that by adopting a suitable level of aggregation, global traffic can be described by means of usual tele-traffic models based on M/G/∞ queues with Weibullian service times. The blobal bit rate can then be approximated by the superposition of Gaussian processes perturbed by a white noise.     

环形IP骨干网

环形网具有很高的生存能力及良好的业务疏导和自愈能力,因此,环形拓扑在传送网中得到了广泛的应用。目前,大多数已建成的SONET传送网或WDM传送网都采用了物理上的环形网结构。尽管本质上环形网由节点间的点到点传输线路组成,但传送网基础设施（包括终端复用器、ADM、DXC等）及光缆线路组成的传输系统平台在电路的调配上却具有相当的灵活性。通过SONET强大的OAM功能,环上节点可在各种子速率下配置成具有不同业务功能的逻辑拓扑结构,如星形、环形、格形等。SONET这种基于同步复接技术的电路调配方式在最初的IP网络规划中也…     

IP over DWDM宽带IP主干网

随着Internet(因特网)主机数的增长以及宽带业务带来的主机业务流量的增加，互联网上业务量以指数形式增加。作为一种最有前途的解决用户需求不断增加的方案。IP overDWDM(基于密集波分复用的互联网协议)受到业界的广泛关注。为此主要讨论了IPoverDWDM技术，包括其原理、关键器件、路由选择以及发展趋势。     

A fast lightweight approach to origin-destination IP traffic estimation using partial measurements

In this paper, a novel approach is proposed for estimating traffic matrices. Our method, called PamTram for PArtial Measurement of TRAffic Matrices, couples lightweight origin-destination (OD) flow measurements along with a computationally lightweight algorithm for producing OD estimates. The first key aspect of our method is to actively select a small number of informative OD flows to measure in each estimation interval. To avoid the heavy computation of optimal selection, we use intuition from game theory to develop randomized selection rules, with the goals of reducing errors and adapting to traffic changes. We show that it is sufficient to measure only one flow per measurement period to drastically reduce errors-thus rendering our method lightweight in terms of measurement overhead. The second key aspect is an explanation and proof that an Iterative Proportional Fitting algorithm approximates traffic matrix estimates when the goal is a minimum mean-squared error; this makes our method lightweight in terms of computation overhead. A one-step error bound is provided for PamTram that bounds the average error for the worst scenario. We validate our method using data from Sprint's European Tier-1 IP backbone network and demonstrate its consistent improvement over previous methods.     

Modeling Internet backbone traffic at the flow level

Our goal is to design a traffic model for noncongested Internet backbone links, which is simple enough to be used in network operation, while being as general as possible. The proposed solution is to model the traffic at the flow level by a Poisson shot-noise process. In our model, a flow is a generic notion that must be able to capture the characteristics of any kind of data stream. We analyze the accuracy of the model with real traffic traces collected on the Sprint Internet protocol (IP) backbone network. Despite its simplicity, our model provides a good approximation of the real traffic observed in the backbone and of its variation. Finally, we discuss the application of our model to network design and dimensioning.     

Wide-area IP multicast traffic characterization

IP multicast is gaining acceptance among service providers as the protocols and infrastructure mature. However, characteristics of multicast traffic remain poorly understood. Using passive OC-12 monitors, we observed multicast traffic on links connecting aggregated customers and peer networks to our native multicast backbone network. We first refined existing traffic flow profiling methodologies via an exploration of temporal differences in multicast packet trains. Based on this framework, we collected multicast flow traces from four geographically dispersed nodes in the Worldcom vBNS network over a one-month period. We present multicast-specific traffic characteristics including packet and flow sizes, fragmentation, sources per group, and address space distribution. Analysis reveals results contrary to prevailing wisdom, including a preponderance of single-packet flows; a highly variable packet size distribution, with many large packets and strong modes; the existence of fragmented multicast traffic; and an insignificant number of simultaneous multiple-source groups. Based on our analysis, we recommend policies for deployment and improvements to protocol implementations.     

基于CERNET主干信道的IP流数据Trace

主干互联网的IP流数据对研究互联网具有重大价值,但实际公布的这类数据量很少,尤其是没有经过抽样处理的原始数据,原因主要在于主干信道采集难度大和IP地址隐私等方面.以CERNET一个省网边界(1G×3)采集的1个小时的连续的IP报头为原始数据,依据相应的省网IP地址构成的特点与实际需求,对IP地址前缀保留匿名化算法Crypto-PAn进行了改进,在提高实现效率的基础上保留了地址类型,用改进后的算法将上述原始数据进行了相应的处理,并将结果在互联网上公布,供有关研究下载.     

构建互联网运营商IP骨干网的高速新平面

计算机和互联网技术的普及催生了大视频、云计算、物联网等各种新兴业务,使得互联网流量极速上涨,传统IP网络架构面临多重挑战。本文提出一种构建运营商IP骨干网的高速新平面的新思路,使得网络具备良好的可扩展性和持续性,并能够有效地保护既有投资,可以有效地应对业务的飞速发展。     

光交换、路由器与P比特级IP网

为了适应广域网（ＷＡＮ）对带宽需求的高速增长，必须以格形全光广域核心网取代现有的同步光环网（ＳＯＮＥＴ）。人们对在核心网络中采用波长交换技术给予了极大的关注，却忽略了光交换技术在核心网边缘的光分组路由器的重大作用。 当今路由器的端口数一般是每束光纤中光纤数目的数倍，这在目前是绰绰有余的，因为可以把每一束光纤当作一个目的地来处理。但是为了有效地利用波长交换，必须把每一个收到的分组搭在适当的波长上以便直接送到距最终目的地最近的节点，从而尽量减少中间路由。当每个路由节点的端口数与它所服务的波长数相当时…     

Feasibility of IP restoration in a tier 1 backbone

Large IP networks usually combine protection and restoration mechanisms at various layers of the protocol stack to minimize service disruption in the event of failures. Sprint has chosen an IP-based restoration approach for building a highly available tier 1 IP backbone. This article describes the design principles of Sprint's network that makes IP-based restoration an effective and cost-efficient approach. The effectiveness of IP-based restoration is evaluated by analyzing network failure characteristics, and measuring disruptions in service availability during controlled failure experiments in the backbone. Current trends for improving the performance of IP-based restoration are also discussed.     

Method for traffic and blocking estimation from test-calling measurements

A method for the estimation of real traffic offered to a trunk from the congestion loss measured with a test-call generator is described. The method consists in simulating both kinds of traffic (real and artificial) and in extracting a relation between the above quantities. Simulations were made for several offered traffic models and test calling rates and led to the construction of tables and diagrams for practical use.     

跨越不同容量设置DWDM网络的动态IP/DWDM综合路由算法研究

IP/DWDM网络的综合路由中的一个重要的研究问题就是如何对跨越不同DWDM网络的IP路由进行综合路由,特别是当两个DWDM网络的容量设置不同时。本文着重解决的就是如何对从单波长带宽大的网络进入单波长带宽小的网络传输的IP业务的综合路由问题。根据尽量鼓励对波长链路的带宽进行完全使用,以减小波长链路带宽碎片的原则,我们提出了两种解决算法:1 n 算法和 m n算法。仿真结果对两种算法的效率和性能进行了测试。     

GARCH model-based large-scale IP traffic matrix estimation

This letter proposes a novel method to estimate large-scale IP traffic matrix (TM). By using the Generalized Autoregressive Conditional Heteroscedasticity (GARCH) to model the Origin-Destination (OD) flows, we can easily get rid of the ill-posed problem of large-scale IP TM. Compared with previous methods, our method does not only hold the lower estimation errors but also is more robust to the noise.     

IP network configuration for intradomain traffic engineering

The smooth operation of the Internet depends on the careful configuration of routers in thousands of autonomous systems throughout the world. Configuring routers is extremely complicated because of the diversity of network equipment, the large number of configuration options, and the interaction of configuration parameters across multiple routers. Network operators have limited tools to aid in configuring large backbone networks. Manual configuration of individual routers can introduce errors and inconsistencies with unforeseen consequences for the operational network. In this article we describe how to identify configuration mistakes by parsing and analyzing configuration data extracted from the various routers. We first present an overview of IP networking from the viewpoint of an Internet service provider and describe the kinds of errors that can appear within and across router configuration files. To narrow the scope of the problem, we then focus our attention on the configuration commands that relate to traffic engineering-tuning the intradomain routing protocol to control the flow of traffic through the ISP network. We present a case study of a prototype tool, developed in collaboration with AT&T IP Services, for checking the configuration of the AT&T IP Backbone and providing input to other systems visualization and traffic engineering     

NetScope: traffic engineering for IP networks

Managing large IP networks requires an understanding of the current traffic flows, routing policies, and network configuration. However, the state of the art for managing IP networks involves manual configuration of each IP router, and traffic engineering based on limited measurements. The networking industry is sorely lacking in software systems that a large Internet service provider can use to support traffic measurement and network modeling, the underpinnings of effective traffic engineering. This article describes the AT&T Labs NetScope, a unified set of software tools for managing the performance of IP backbone networks. The key idea behind NetScope is to generate global views of the network on the basis of configuration and usage data associated with the individual network elements. Having created an appropriate global view, we are able to infer and visualize the networkwide implications of local changes in traffic, configuration, and control. Using NetScope, a network provider can experiment with changes in network configuration in a simulated environment rather than the operational network. In addition, the tool provides a sound framework for additional modules for network optimization and performance debugging. We demonstrate the capabilities of the tool through an example traffic engineering exercise of locating a heavily loaded link, identifying which traffic demands flow on the link, and changing the configuration of intradomain routing to reduce the congestion     

Dimensioning IP access links carrying data traffic

This paper proposes simple dimensioning rules for high speedip access links carrying data traffic. Assuming a finite source population and fair bandwidth sharing among user flows, we derive formulas relating capacity, demand and performance. These formulas allow link dimensioning for a target quality of service expressed in terms of useful per-flow throughput. They constitute a data traffic model equivalent of the Engset model for telephone access networks. Performance is shown to be largely independent of detailed traffic characteristics such as the statistical distributions of flow size and think time. Simple approximations are derived for two distinct performance regimes corresponding to transparency and saturation, respectively. Extensions to the basic model account for a heterogeneous user demand, unfair bandwidth sharing or different access rate classes. In any case, the key parameter for dimensioning is the offered traffic, defined as the average data rate a user would generate in the absence of congestion.     

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