Poor Performance: Is It The Application Or The Network?

As more networked applications are deployed it becomes harder to determine the cause of poor performance since complex interactions, multidisciplinary in nature, occur between the application and the network across several areas of responsibility. Developers\u27 choice of application architecture, algorithms, and communications protocol have significant performance impacts, and network design, both hardware and software, are chosen by network administrators, while the final performance impact comes from other application traffic in the network competing for resources. In addition to this dynamic hardware/software complexity, end-users are becoming more sophisticated and insisting on higher Quality of Experience (QOE). This term refers to performance the end-user requires, on a per application end-to-end basis, from each subsystem along the way. Some even extend the term to include the Network Management business functions such as service provisioning, service level agreements (SLAs), and customer care functions. Human Computer Interaction, Network Quality of Service, and Application, Server, Data Base and Data Storage research all contribute to QOE theory and practice. This paper examines the use of modeling and simulation to gain insight into application QOE prior to deployment. It focuses on the network contribution to over all quality by examining two application types, possible deployment scenarios and their performance in those scenarios. Utilizing these techniques would enable practitioners of one area (for example network managers or ISPs) to evaluate their ability to deliver QOE