5 - SLA and Network Monitoring

Abstract

This chapter discusses the technologies and techniques available for service level agreement (SLA) and network monitoring in quality of service-enabled Internet Protocol (QOS-enabled IP) networks. There are two main approaches that are generally used to monitor the performance of a QOS-enabled network service to determine whether SLAs have been or can be met: passive network monitoring and active network monitoring. Unlike passive monitoring, active monitoring involves sending additional traffic into the network. Passive and active network monitoring systems may be deployed for a number of reasons: (1) for monitoring and reporting that the network service offered is achieving the committed SLA targets, (2) for monitoring that network performance is sufficient to meet the required application quality of experience targets, and (3) as a feedback loop to network capacity planning processes, results from passive and active monitoring may provide heuristics, allowing capacity planning thresholds to be tuned based upon correlation between network or per-class load and SLA probing reports of delay, jitter, and loss.