Monitoring Ports
You can designate a port to be a monitor port. This action forwards
the port's incoming and outgoing traffic to another port and frees it for use
with the Switch Port Analyzer (SPAN). You can then troubleshoot network problems
by examining traffic on other ports or segments.
Any port can be a monitor port, with these restrictions:
- A monitor port must be a static-access port.
- A monitor port cannot be in a Fast EtherChannel
or Gigabit EtherChannel port group.
- An ATM port cannot be a monitor port but can be monitored.
- A monitor port cannot be enabled for port security.
- A monitor port cannot be a multi-VLAN port.
- A monitor port must be a member of the same VLAN as the port monitored.
VLAN membership changes are not allowed on monitor ports and ports being monitored.
- A monitor port cannot be a dynamic-access port or a trunk port. However, a static-access port can monitor
a VLAN on a trunk port.
The VLAN monitored is the one associated with the static-access port.
The SPAN window shows you which port,
if any, is being used as a monitor port. It also allows you to reassign monitoring
to another port. To open the SPAN window, choose Port > SPAN.