Unable to get 3750 Stack to work using StackWise cables

Unanswered Question
Feb 13th, 2007

I have provided initial configuration for each of two 3750 switches. I have connected a stackwise cable from stackwise port one of the first 3750 to the stackwise port two of the second 3750. The two switches both think they are masters and do not talk to each other. A show switch command on either switch shows only one switch which is master with no member switch. A show switch stack-ports shows switch number 1 with ports 1 and 2 both down. A show switch stack-ring shows 29,165 frames sent to stack ring. How to I get the two switches to recognize each other and form a stack?

I have this problem too.
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John Patrick Lopez Tue, 02/13/2007 - 19:32

have you tried rebooting both switches simultaneously? because during boot, the switch will wait for 30 seconds (i don't remember the exact time) to detect a stacked switch.

steveoppermann Wed, 02/14/2007 - 03:37

I have powered them up within a few seconds of each other. I have seen the following information which I believe is what you are refering to:

From the Cisco Network Modules Hardware Install Manual: If you have no preference about which Cisco EtherSwitch service module becomes the stack master,

power up both Cisco EtherSwitch service modules in the stack within 10 seconds. These Cisco EtherSwitch service modules participate in the stack master election.

steveoppermann Wed, 02/14/2007 - 07:56

I tried a new cable and connected from Stackwise port one on one switch to Stackwise port one on the other switch (instead of port one on one switch to port two on the other switch). It is now working well - one is master and the other is a member switch. I am not sure yet if it was the cable or the way it was connected (I can't find any clear documentation on how the Stackwise ports are supposed to be connected).

nayanpanchal Wed, 02/28/2007 - 00:56

According to Cisco, if you want to create stack with two switches:

connect Port 1 of Swith 1 to Port 2 of Switch 2 and vice versa.

Say you have three switches then,

Port 1-Switch 1 to Port 2 switch 2.

Port 1-Switch 2 to Port 2 switch 3.

Port 1-switch 3 to Port 2 switch 1.

Hope this helps.

kramseyer Fri, 03/02/2007 - 10:40

We have seven 3750 TS48 Ethernet switches and two 3750 TS16 Ethernet uplinks in a stack configuration:

3750 TS16 Ethernet Uplink #1 (priority 15)

3750 TS48 Ethernet Switch #1 (priority 1)

3750 TS48 Ethernet Switch #2 (priority 1)

3750 TS48 Ethernet Switch #3 (priority 1)

3750 TS48 Ethernet Switch #4 (priority 1)

3750 TS48 Ethernet Switch #5 (priority 1)

3750 TS48 Ethernet Switch #6 (priority 1)

3750 TS48 Ethernet Switch #7 (priority 1)

3750 TS16 Ethernet Uplink #2 (priority 9)

This stack configuration works fine; however, if all switches & uplinks in the stack are powered off and then powered on together, we have seen the two 3750 TS16 Ethernet Uplinks on the ends become stack masters at the same time. We thought the top 3750 TS16 Ethernet Uplink should be the stack master because it has this highest stack priority (15).

Any idea why we are sometimes getting two stack masters during a POR?


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