We will need to add the third unit SWT3 (S5700LI) having below stack-port configuration and using Xgi2/0/4 we will connect it to xGi1/0/3.
1. Add Xgi1/0/3 to stack-port 1/1
2. Save and power off SWT3
3. Plug in the stack cable. (between XGigabitEthernet2/0/4 and XGigabitEthernet1/0/3)
4. Power on SWT3
SWT1 and SWT2 are still running.
The new stack system, with 3 switches.
The stack-port configuration:
Now we will add the forth unit SWT4. We will configure stack-port as below, using XGigabitEthernet3/0/4 to connect with XGigabitEthernet2/0/3.
1. save and power off SWT4
2. plug the stack cable between Xgi3/0/4 and Xgi2/0/3
3. power on SWT4.
The stack system is still running while adding the new device.
wait for a couple of minutes....
Stack port configuration:
Hope you will find this case useful!