Switch Port Analyzer (SPAN)

Cisco^® Systems’ port mirroring feature. Port mirroring (also called port monitoring) is used on network switches to send a copy of network packets seen on one switch port to a network monitoring connection on another switch port. This is commonly used for network appliances that require monitoring of network traffic, such as an intrusion-detection system. Network administrators use port mirroring to analyze and debug data or diagnose errors on a network. It helps the administrator keep a close eye on network performance and generates an alert when problems occur.