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3750 Stacking

I need some assistance.. If I look at the 3750 install guides kit gives you two options for installing the stacking cables. One way it shows for three switches from switch one port one to port one on switch two , from port two on switch to port one on switch three and then from port two on swith two to port two on switch one.

This provides full duplex on stack cable failures.

The second way show going from port one switch one to port two switch two and port one on switch two to port twp on switch three then from port one switch three back to port two on switch one.. again reason appears to be half duplex on cable failure..

I have always used the second method but my question is with two switches what is the best way to place the stack cables.. between port one on switch one and port one on switch two , and port two on switch one and to port two on switch two or from port one switch one to port two on switch two and from port two on switch one to port one on switch two.

what way is best?

Hope this all makes sense ..


Re: 3750 Stacking

Hi Mike,

I have always used SwP1-Sw2P2 and Sw1P2 tp Sw2P1 combination.

Here is the documents which will help you further

Hope this Helps.........


New Member

Re: 3750 Stacking

Thank you,,, Thats what I have also always done.. The 3750 install guide doesnt agree.,, Thanks I will remain doing it this way,I also hav an issue where the guys installd the second stacj cable after the switch had been running for a month or so .. The 3750 doesnt see the second cable so I guess I have to power down the stack and re power.


New Member

Re: 3750 Stacking

We have 3750's switch stacks in our environment. We will occasionally get the same situation. Error message about switchport down. One switch port in stack can't talk to another.

We try replacing stack cable first. That usually works. Don't know if it's the cable that's defective, or changing the cable resets the switch port.


Re: 3750 Stacking

Try using using a screwdriver to tighten the screws down , not too tight though. We have seen if they are even a little loose they will no tcome up .

New Member

Re: 3750 Stacking

FYI ... There's the third way to connect 3 or more switches I found somewhere in the Cisco documentation. It's used for when you don't want, or don't have, a 3 meter stack cable. You basically skip every other switch, and connect the end switches,

3 Switch - (S1-S3, then connect ends with S1-S2 & S2-S3)

SW1 P1 - SW2 P1

SW1 P2 - SW3 P1

SW2 P2 - SW3 P2

Allows you to add a fourth switch without breaking the stack. Just disconnect the last link (the SW2 P2 - SW3 P2 connection), and add the fourth switch like this.

4 Switch (S1-S3, S2-S4, and then S1-S2 & S3-S4)

SW1 P1 - SW2 P1 (same as above)

SW1 P2 - SW3 P1 (same as above)

SW2 P2 - SW4 P1

SW3 P2 - SW4 P2

You can keep adding switches by breaking the last link, and adding switches without breaking stack. No performance benefit that I can see. Just a method to cable multiple switches, or add additional switches without breaking stack, without 3 meter stack cable.

Easier to understand if you diagram.

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