LAN Switching first-step

Switch Port Analyzer (SPAN)

Switched Port Analyzer (SPAN), sometimes called port mirroring or port monitoring, copies switch network traffic and forwards it out the SPAN port for analysis by a network analyzer. By enabling the SPAN, you can monitor traffic on a switch port by forwarding incoming and outgoing traffic to another port for data collection and analysis. You can use a network analyzer on this monitor port to troubleshoot network problems by examining traffic on other ports or segments without taking the network out of service.

Suppose, for instance, that you want to examine traffic flowing in and out of a port, or within a virtual local-area network (VLAN). In a shared network, such as Ethernet, you would attach a network analyzer ...