Monitor: Loop Guard
Overview
This section provides information for Loop Guard in Monitor.
Loop guard is designed to handle loop problems on the edge of your network. This can occur when a port is connected to a Switch that is in a loop state. Loop state occurs as a result of human error. It happens when two ports on a switch are connected with the same cable. When a switch in loop state sends out broadcast messages the messages loop back to the switch and are re-broadcast again and again causing a broadcast storm.
If a switch (not in loop state) connects to a switch in loop state, then it will be affected by the switch in loop state in the following way:
It will receive broadcast messages sent out from the switch in loop state.
It will receive its own broadcast messages that it sends out as they loop back. It will then re-broadcast those messages again.
The loop guard feature checks to see if a loop guard enabled port is connected to a switch in loop state. This is accomplished by periodically sending a probe packet and seeing if the packet returns on the same port. If this is the case, the Switch will shut down the port connected to the switch in loop state.
Loop Guard
Use the Loop Guard screen to view Switch loop guard status. Click Monitor > Loop Guard.
Each field is described in the following table.
Monitor > Loop Guard
Label
Description
Loop Guard
Port
This field displays a port number.
Status
This field displays the status.
Time Left (sec)
This field displays the amount of time left in seconds.
Action
This field displays the action.