Comment by wjholden
1 year ago
Cisco switches can mirror ports with a feature called Switch Port Analyzer (SPAN). For a monitored port, one can specify the direction (frames in, out, or both), and the destination port or VLAN.
SPAN ports are great for network troubleshooting. They're also nice for security monitors, such as an intrusion detection system. The IDS logically sees traffic "on-line," but completely transparent to users. If the IDS fails, traffic fails open (which wouldn't be acceptable in some circumstances, but it all depends on your priorities).
When I think "Cisco" I think error-free. /s
No, really, I get where you and your parent are coming from. It is a low probability. But occasionally there is also thoroughly verified application code out there. That is when you are asking yourself where the error really is. It could be any layer.