Stacking Cisco 3750G Switches

Stacking Cisco 3750G switches is very easy. Almost no configuration at all. This example will be for “two” Cisco 3750G switches.

The only prerequesite for stacking Cisco 3750G switches is that they both are running the same IOS.

Using the supplied stacking cables connect to Stack Port 1 on the switch that you want to be Stack Member 1. (Usually the one on top) Then connect the other end of the stack cable to Stack Port 2 on the second switch or Stack Member 2. Now connect Stack Port 2 on Stack Member 1 to Stack Port 1 on Stack Member 2. Both cable will be crisscrossed. I have illustrated this in my table below.  Stack Member 01 Port 1 to Stack Member 02 Port 2 and vice versa.

To verify that the switches are stacked correctly use the front panel button and LED’s to verify proper stacking configuration. Click the button until you reach the stack LED, you will notice the last two Fiber SFP ports will be lit up green and the first two ethernet ports will be green and flashing.

Also, on the front panel LED will show which switch is the Stack Master. You will have a green LED lit up where it says master.

You will probably want to set the priority of what switch your want to be the stack master. This will ensure that in case the switches reboot the one you want as your primary or stack master will always be the master.

switch> en

switch# sh switch

Switch/Stack Mac Address : 2222.2222.0002

H/W Current

Switch# Role Mac Address Priority Version State

———————————————————-

1 Member 1111.1111.0001 1 0 Ready

*2 Master 2222.2222.0002 1 0 Ready

The output of the show switch command verfies that the 2nd switch is the Stack Master. Well, we want the 1st switch to be the Stack Master in this example. Also, the output show the Priority of both switches in the stack, they are set to Priority 1. Having both switches set to this priority could result in a swap of which swtich is the Master if a reboot occurs. Will will need to set the priority manually to ensure this never happens. The commands to do so is as follows:

switch# config t

switch(config)# switch 1 1 5

switch(config)# end

switch# wr mem

switch# reload

We have now just changed the priority of the 1st switch to 5 and wrote the config to memory and reloaded. When the switches boot back up the 1st switch will be the master and we can verify this by the front panel LED or issuing the “show switch” command

switch# sh switch

Switch/Stack Mac Address : 1111.1111.0001

H/W Current

Switch# Role Mac Address Priority Version State

———————————————————-

*1 Master 1111.1111.0001 5 0 Ready

2 Member 2222.2222.0002 1 0 Ready

Accessing switchports will be exactly the same for the first switch, but will be a little different for the second

To access switchports on the first switch:

switch> en

switch# config t

switch(config)# int gi1/0/15

To access ports on the second switch:

switch(config)# int gi2/0/15

Thats it, stacking switches is very simple and gives you ONE management IP address for both switches. The links between the switches also have a 32GB thoughput or 16GB x 16GB. Sure beats a crossover cable with 1GB thoughput and TWO IP address to manage both switches.