An unified VoIP model for workload generation

• Published in: Multimedia tools and applications Vol. 70; no. 3; pp. 2309 - 2329
• Main Authors: Mattos, Carlos Ignacio, Ribeiro, Eduardo Parente, Fernandez, Evelio Martín García, Pedroso, Carlos Marcelo
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01.06.2014; Springer; Springer Nature B.V
• Subjects: Access methods and protocols, osi model; Accuracy; Algorithmics. Computability. Computer arithmetics; Analysis; Applied sciences; Cellular telephones; Codec; Computer Communication Networks; Computer Science; Computer science; control theory; systems; Computer simulation; Computer systems and distributed systems. User interface; Data Structures and Information Theory; Exact sciences and technology; Internet telephony; Intervals; Laboratories; Multimedia communications; Multimedia Information Systems; Probability distribution; Quality of service; Software; Special Purpose and Application-Based Systems; Studies; Telecommunications; Telecommunications and information theory; Telephones; Teleprocessing networks. Isdn; Theoretical computing; Traffic engineering; Traffic flow; User behavior; Voice; VoIP (protocol); Workload; Workloads; Traffic models; Workload generation; Voice over IP; Backbone; Exponential distribution; Internet protocol; Transmission protocol; Voiced signal; Jitter; Telecommunication; Probability distribution; Computational complexity; Modeling; Delay; Workload; Codec; Pareto distribution; Traffic management; Time interval; Simulator; Voice; User behavior
• ISSN: 1380-7501; 1573-7721
• DOI: 10.1007/s11042-012-1243-5

This paper presents a new model for VoIP workload generation. The novelty of our proposal consists in modeling the sessions by characterizing both the user behavior (session level) and the packet generation for an active call (intra-session level) with easily measured parameters and low computational complexity. This approach also facilitates systematic study of changes in user behavior and voice codec. The session level was modeled by analysis of call-holding time and time interval between successive calls. The model for call-holding time, characterizing the individual user behavior, uses the Pareto type 2 probability distribution. The time interval between calls is obtained from aggregate traffic and can be modeled by exponential probability distribution. Aggregate traffic is obtained by superposition of simultaneous sessions. The data used to characterize the session level were collected at the backbone of two Brazilian telecommunication carriers. The model for intra-session level comprises the characterization of the packet size and the packet inter-arrival time. The intra-session model was based on data generated in a laboratory environment, in order to properly characterize the codec influence on packet generation and to avoid the effects of delay, jitter and loss commonly present in an operational network. Models for constant bit rate and variable bit rate codecs were considered. A simulator was implemented and the results indicate that our model properly mimics the characteristics observed in real traffic and can be used for VoIP modeling and workload generation. Additionally, an application to automate the performance analysis was developed.