Experiences with Evaluating Network QoS for IP Telephony

Successful deployment of networked multimedia applications such as IP Telephony depends on the performance of the underlying data network. QoS requirements of these applications are different from those of traditional data applications. For example, while IP Telephony is very sensitive to delay and jitter, traditional data applications are more tolerant of these performance metrics. Consequently, assessing a network to determine whether it can accommodate the stringent QoS requirements of IP Telephony becomes critical. In this paper we describe a technique for evaluating a network for IP Telephony readiness. Our technique relies on the data collection and analysis support of our prototype tool, ExamiNet TM. ExamiNetTM automatically discovers the topology of a given network and collects and integrates network device performance and voice quality metrics. We report the results of assessing the IP Telephony readiness of a real network of 31 network devices (routers/switches) and 23 hosts via ExamiNetTM. Our evaluation identified links in the network that were over utilized to the point at which they could not handle IP Telephony.