Physical hardware network hubs are a thing of the past, their major identifying technology, known as port mirroring, has been commonly integrated into higher quality routers and switches. The product listed below support this technology.
What is Port Mirroring?
Port Mirroring is a network monitoring method used by hubs or intelligent switches/routers where copies of network packets are forwarded to another switch port and analyzed. It is commonly used on network appliances that require monitoring of network traffic for intrusion detection systems.
Network Administrators use this technology as a diagnostic tool to prevent or fend off an attack on their networks, debug data and diagnose errors on a network. Port Mirroring can be used to mirror inbound or outbound traffic on single or multiple interfaces physically or virtually.
Cisco refers to this technology as Switched Port Analyzer (SPAN) on their equipment and 3com commonly refers to it as Roving Analysis Port (RAP) on their switches.