An element of network management, performance management comprises the collection and analysis of data regarding the performance of network elements (NEs), systems, and networks. A network management system (NMS) responsible for an IP network, for example, might gather and analyze performance data from multiple routers with respect to errored packets, lost packets, queue lengths, and packet jitter. Based on that analysis, the NMS might reroute packet traffic between two edge routers. See also jitter, NE, network management, NMS, and queue.