Experiences with evaluating network QoS for IP telephony

Bearden, A.; Denby, Lorraine; Karaçali, B.; Meloche, J.; Stott, D.T.

doi:10.1109/iwqos.2002.1006594

Cited by 7 publications

(6 citation statements)

References 15 publications

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“…Our measurement strategy involves collecting end-to-end statistics between potential IP Telephony endpoint locations similar to the approach of the ExpertNetTM tool suite described in [1], [2], [3]. Measurement devices in ExpertNetTM are small single board computers which can be easily deployed anywhere in the network.…”

Section: Preliminariesmentioning

confidence: 99%

“…The coverage criteria proposed in this section are motivated by our earlier experience with network assessments [1], [2], [3]. An accurate and efficient analysis of network performance is possible if (a) most of the links in the network are exercised and (b) most of the links in the network are estimable.…”

Section: Endpoint Placement Algorithmsmentioning

confidence: 99%

“…An empirical network assessment approach was recently introduced by the ExpertNetTM tool suite [1], [2], [3]. In this approach, small measurement devices (single-board computers) are distributed across the network to actively collect endto-end measurements.…”

Section: Introductionmentioning

confidence: 99%

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Network Instrumentation for End-to-End Measurements

Karaçali

Rao

2007

2007 10th IFIP/IEEE International Symposium on Integrated Network Management

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An important consideration when deploying realtime applications such as IP Telephony is how to ensure that the network delivers the stringent QoS requirements of these applications. Prior to deployment, assessing whether an enterprise network can handle IP Telephony ensures a successful deployment. A network assessment approach recently introduced in the ExpertNetTM tool suite involves distributing small measurement devices in the network. These devices inject synthetic RTP traffic and collect end-to-end measurements that represent end-to-end call quality. In this approach, the placement of measurement devices impacts the network coverage and accuracy of the analysis. In this paper, we address the problem of how to place such measurement devices in a network to ensure a comprehensive analysis. Specifically, we focus on two issues: first where to place network measurement devices when the network topology is known and second how to estimate the number of such devices in the absence of network topology information. In this paper, we address the first problem by providing two heuristic algorithms for placing measurement devices in a given network. We evaluate these heuristics using synthetic networks. We address the second problem by proposing a technique to estimate the number of measurement devices using the size of a network. To evaluate the performance of our technique, we conducted a study on actual enterprise network topologies. Using our technique, we predicted the number of endpoints based on network size and compared these figures to the number of endpoints placed by the proposed algorithms using the network topology. Our results indicate that the predictions are comparable to the number of endpoints placed using the actual enterprise network topology.

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Section: Preliminariesmentioning

confidence: 99%

Section: Endpoint Placement Algorithmsmentioning

confidence: 99%

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Network Instrumentation for End-to-End Measurements

Karaçali

Rao

2007

2007 10th IFIP/IEEE International Symposium on Integrated Network Management

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“…For discussions of other problems, an issue of Statistical Science contains three companion review articles that survey many recent developments in the field: see Duffield [5], Castro et al [4], and Cao et al [3], each of which also points to many further references. Our research interests have grown out of the needs to develop technology to test and assess enterprise networks for VoIP Quality of Service (QoS); see Bearden, et al [1,2] and Karacali, et al [6].…”

Section: Introductionmentioning

confidence: 99%

Using data network metrics, graphics, and topology to explore network characteristics

Adhikari¹,

Denby²,

Landwehr³

et al. 2007

Complex Datasets and Inverse Problems

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Yehuda Vardi introduced the term network tomography and was the first to propose and study how statistical inverse methods could be adapted to attack important network problems (Vardi, 1996). More recently, in one of his final papers, Vardi proposed notions of metrics on networks to define and measure distances between a network's links, its paths, and also between different networks (Vardi, 2004). In this paper, we apply Vardi's general approach for network metrics to a real data network by using data obtained from special data network tools and testing procedures presented here. We illustrate how the metrics help explicate interesting features of the traffic characteristics on the network. We also adapt the metrics in order to condition on traffic passing through a portion of the network, such as a router or pair of routers, and show further how this approach helps to discover and explain interesting network characteristics.

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“…(See also Bearden, Denby, Karacali, Meloche, andStott 2002a,b andMeloche 2004 for other studies based on data collected from this network.) This figure shows parts of the Avaya corporate network, including 37 special communication endpoints that are labeled in the figure.…”

Section: Introductionmentioning

confidence: 99%

Statistical Aspects of the Analysis of Data Networks

et al. 2007

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Assessing and monitoring the performance of computer and communications networks is an important problem for network engineers. A considerable amount of work has been done on tools and techniques for data collection, modeling, and analysis within the network research community. This article presents an overview of the engineering problems and statistical issues, describes recent research developments, and summarizes ongoing work and areas for further research. Although there are many interesting issues related to network analysis, our focus here is on estimating and monitoring network quality-of-service parameters. We discuss methods for estimating edge-level parameters from end-to-end path-level measurements, an important engineering problem that raises interesting statistical modeling issues. Other topics include network monitoring, network visualization, and discovery of network topology. Data from a corporate network are used to illustrate the problems and techniques. As in any overview, the discussion is likely to be slanted toward the authors' own research interests.

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Experiences with evaluating network QoS for IP telephony

Cited by 7 publications

References 15 publications

Network Instrumentation for End-to-End Measurements

Network Instrumentation for End-to-End Measurements

Using data network metrics, graphics, and topology to explore network characteristics

Statistical Aspects of the Analysis of Data Networks

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