On Active Measurements in QoS-Enabled IP Networks
Rick Whitner, Graham Pollock · 2002
Network monitoring applications are often used by service providers to monitor compliance with service level agreements (SLAs) made with customers and to trigger troubleshooting activities when service drops below guaranteed levels. These applications can also play a role in determining the amount of compensation service providers must give when service guarantees are not met. Many performance monitoring applications rely on active measurement techniques, which involve injecting traffic into the network and then measuring relevant characteristics of that traffic. A challenge in QoSenabled IP networks is that traffic is handled differently according to traffic handling policy configured into network elements. Unless the monitoring application can determine the network’s QoS configuration and react accordingly, it might incorrectly measure the QoS behavior of the network. This paper examines the issue of matching active measurements to the network’s QoS configuration when monitoring a QoS-enabled IP network. First, we illustrate the issue using common active measurement techniques. Next, we examine approaches to matching active measurements to the network’s QoS configuration. Finally, we present our experiences in prototyping one approach.