STOCHASTIC MODELING AND TIME-TO-EVENT ANALYSIS OF VOIP TRAFFIC

Voice over IP (VoIP) systems are gaining increased popularity due to the cost effectiveness, ease of management, and enhanced features and capabilities. Both enterprises and carriers are deploying VoIP systems to replace their TDM-based legacy voice networks. However, the lack of engineering models for VoIP systems has been realized by many researchers, especially for large-scale networks. The purpose of traffic engineering is to minimize call blocking probability and maximize resource utilization. The current traffic engineering models are inherited from the legacy PSTN world, and these models fall short from capturing the characteristics of new traffic patterns. The objective of this research is to develop a traffic engineering model for modern VoIP networks. We studied the traffic on a large-scale VoIP network and collected several billions of call information. Our analysis shows that the traditional traffic engineering approach based on the Poisson call arrival process and exponential holding time fails to capture the modern telecommunication systems accurately. We developed a new framework for modeling call arrivals as a non-homogeneous Poisson process, and we further enhanced the model by providing a Gaussian approximation for the cases of heavy traffic condition on large-scale networks. In the second phase of the research, we followed a new time-to-event survival analysis approach to model call holding time as a generalized gamma distribution and we introduced a Call Cease Rate function to model the call durations. The modeling and statistical work of the Call Arrival model and the Call Holding Time model is constructed, verified and validated using hundreds of millions of real call information collected from an operational VoIP carrier network. The traffic data is a mixture of residential, business, and wireless traffic. Therefore, our proposed models can be applied to any modern telecommunication system. We also conducted sensitivity analysis of model parameters and performed statistical tests on the robustness of the models’ assumptions. We implemented the models in a new simulation-based traffic engineering system called VoIP Traffic Engineering Simulator (VSIM). Advanced statistical and stochastic techniques were used in building VSIM system. The core of VSIM is a simulation system that consists of two different simulation engines: the NHPP parametric simulation engine and the non-parametric simulation engine. In addition, VSIM provides several subsystems for traffic data collection, processing, statistical modeling, model parameter estimation, graph generation, and traffic prediction. VSIM is capable of extracting traffic data from a live VoIP network, processing and storing the extracted information, and then feeding it into one of the simulation engines which in turn provides resource optimization and quality of service reports

Optimizing Service Differentiation Scheme with Sized-based Queue Management in DiffServ Networks

In this paper we introduced Modified Sized-based Queue Management as a dropping scheme that aims to fairly prioritize and allocate more service to VoIP traffic over bulk data like FTP as the former one usually has small packet size with less impact to the network congestion. In the same time, we want to guarantee that this prioritization is fair enough for both traffic types. On the other hand we study the total link delay over the congestive link with the attempt to alleviate this congestion as much as possible at the by function of early congestion notification. Our M-SQM scheme has been evaluated with NS2 experiments to measure the packets received from both and total link-delay for different traffic. The performance evaluation results of M-SQM have been validated and graphically compared with the performance of other three legacy AQMs (RED, RIO, and PI). It is depicted that our M-SQM outperformed these AQMs in providing QoS level of service differentiation.Comment: 10 pages, 9 figures, 1 table, Submitted to Journal of Telecommunication

Detailed Analysis of Skype Traffic

Skype is beyond any doubt the VoIP application in the current Internet application spectrum. Its amazing success has drawn the attention of telecom operators and the research commu- nity, both interested in knowing its internal mechanisms, charac- terizing its traffic, understanding its users' behavior. In this paper, we investigate the characteristics of traffic streams generated by voice and video communications, and the signaling traffic generated by Skype. Our approach is twofold, as we make use of both active and passive measurement techniques to gather a deep understanding on the traffic Skype generates. From extensive testbed experiments, we devise a source model which takes into ac- count: i) the service type, i.e., SkypeOut calls or calls between two Skype clients, ii) the selected source Codec, iii) the adopted trans- port layer protocol, and iv) network conditions. Leveraging on the use of an accurate Skype classification engine that we recently pro- posed, we study and characterize Skype traffic based on extensive passive measurements collected from our campus LA

Legislative and Regulatory Strategies for Providing Consumer Safeguards in a Convergent Information and Communications Marketplace

The Federal Communications Commission desires to apply a single regulatory category to services and service providers, a process the Commission can achieve when ventures concentrate on one function and offer one readily identifiable service, such as telephony. However, technological convergence, digitization and the ability of the Internet to handle many different service types within a single bitstream now make it possible for companies to offer quadruple play bundles of wireless and wireline telephony, video, and Internet access services. Following Comcast Corp. v. FCC, the FCC must rethink how to best serve the public interest and safeguard consumers. Absent a legislative remedy, the FCC has experienced great difficulty in finding ways to sanction ISP anticompetitive practices regulations within the Commission\u27s limited statutory authority. This article explains how the FCC backed itself into a corner when it sought to free the Internet of most regulatory oversight by determining that the information service classification applies to all Internet access technologies. Facing complaints about ISP anticompetitive practices, the FCC currently lacks explicit statutory authority to provide a needed remedy. The article also provides recommendations on how Congress and the FCC might recognize that convergent services, such as Internet access, combine both unregulated information service and telecommunications components in much the same way as wireless cellular telephone companies. The article recommends that in light of the ascending importance of Internet access and the lack of sustainable competition that would foster effective self-regulation, Congress should amend the Communications Act to authorize the FCC to apply limited Title II safeguards to ISPs that already wireless telephony

Optimizing Low Speed VoIP Network for Rural Next Generation Network (R-NGN)

In this paper, we identify some impairments in the Voice over Internet Protocol (VoIP) networks and quantify the levels of voice quality. We propose an optimization model to maximize number of calls in low speed network for Rural Next Generation Network (R-NGN) while maintaining a minimum level of voice quality. The model is based-on Extended E-model to select parameters like voice coder, packet loss level, jitter buffer size, and network utilization. The optimum VoIP access network is achieved by applying G.723.1 5.3 kbps voice coder, packet loss level less than 1%, jitter buffer 50 ms, and network utilization less than 85%

Anomaly Detection in VoIP Traffic with Trends

In this paper we present methodological advances in anomaly detection, which, among other purposes, can be used to discover abnormal traffic patterns under the presence of deterministic trends in data, given that specific assumptions about the traffic type and nature are met. A performance study of the proposed methods, both if these assumptions are fulfilled and violated, shows good results in great generality. Our study features VoIP call counts, but the methodology can be applied to any data following, at least roughly, a non-homogeneous Poisson process (think of highly aggregated traffic flows)

The Growth of the Broadband Internet Access Market in California: Deployment, Competition, Adoption, and Challenges for Policy (Research Brief)

This report is a brief version of a longer study of the California broadband market (Paper 63). Readers interested in more background information, more empirical analysis, and more complete documentation of sources and methodology can refer to the longer report, which is available at: http://digitalcommons.pepperdine.edu/sppworkingpapers/63/