Computers Voice-Over-Ip (Voip) Performance Testing

Computers

Voice-over-IP (VoIP) Performance Testing Tools

Voice over IP (VoIP) technology offers a wide range of benefits that include reduction of telecom costs, management of one network instead of two, simplified provisioning of services to remote locations, and the ability to deploy a new generation of converged applications. VoIP network performance testing can indicate the distinction between a VoIP system working at a high level and a weak system that runs so poorly that customers could take their business elsewhere. Every company that is considering the benefits of VoIP must take steps in order to guarantee that their united network delivers acceptable call quality and non-stop availability (VoIP performance testing fundamentals, 2007).

A virtual network test bed is mainly useful for taking risk out of both initial VoIP deployment and long-term VoIP possession. Basically, a test bed allows application developers, QA specialists, network managers and other it staff to view and analyze the behavior of network applications in a lab environment that precisely follows conditions on the current or planned production network. This kind of test bed is indispensable for modeling the performance of VoIP in the production environment, validating vendor claims, comparing alternative solutions, experimenting with proposed network enhancements, and actually experiencing the call quality that the planned VoIP implementation will deliver (VoIP performance testing fundamentals, 2007).

VoIP testing can be broken down into two distinct areas -- pre-deployment testing and post deployment testing. Pre-deployment testing reduces the risk by allowing one to run realistic and worst-case scenario testing under controlled circumstances. Traffic generation, network traffic analysis and IP network recreation are all very important tools that can help decrease the risk. Apparent voice quality on VoIP systems is severely affected by packet loss, packet delay and jitter which are variable packet arrival times. All of these things can be inherent to any packet-based system. The solution is to alter networks, giving higher priority to VoIP traffic, but this can negatively affect the performance of other applications. Altering the parameters of a live network can be a time-consuming and troublesome process. Another option is to use a network simulator which is a device that allows you to exactly model the target network and then see the effect of changing key factors such as routing, link speeds and priorities (Voice-over-IP (VoIP) and network performance, 2007).

The questions that arise after deployment include: is the VoIP system delivering adequate perceived voice quality? And Is the VoIP application affecting the performance of other applications? Voice is, by definition, analogue in nature and voice quality is highly subjective and the same network may deliver different perceived quality for different voice types. When it comes to measuring voice quality, there are two essential advances- analogue and digital. An analogue voice quality tester works by producing a real voice call across a network and weighing it against the received call with the reference call. A digital voice quality tester works by analyzing the packet data stream containing the VoIP data and measuring packet loss, packet delay and packet jitter. This information is then used to calculate the likely voice quality, expressed as predictive Mean Opinion Score (MOS) (Voice-over-IP (VoIP) and network performance, 2007).