A:

You can perform the following operations to rectify the fault:

Step 1: Check whether member switch models support the stacking function.

a)        Obtain the switch model based on the device appearance or by running the display device command.

b)       Check whether the switch model supports stacking. For details, see the How Do I Obtain Information About S series Switches Stacking Support?

Step 2: Check whether stack cables meet requirements.

Determine whether stack cables meet requirements based on the stack configuration notes. For details about how to obtain the stack        configuration notes, see the How Do I Obtain Information About S series Switches Stacking Support?

Step 3: Check whether stack ports are correctly connected.

 Run the display stack peers command to check whether the stack ports are correctly connected.

Run the display stack channel all command to check whether stack port connections are correct. That is, STACK1 of the local switch must be connected to STACK2 of the other switch.

Step 4: Check whether stack ports are Up.

Run the display stack port brief command to check whether the stack ports and member ports are Up. If not, check the reason why the ports go Down and enable the ports to go Up. The possible causes for port Down include: Cables are faulty or the ports are shut down manually.