In this post , we explain in detail step by step tested and working procedure to stack two Cisco switches. In our setup , we have verified stacking two Cisco L3 3750 48 port + 4G switches which had 2 stack ports each. Before stacking , verify the switch slot number and MAC address as below. If required backup your switch configurations using "copy flash: ftp:" command as described in our earlier posts.
Switch1# show switch
Switch/Stack Mac Address : 001c.23b1.e298
H/W Current
Switch# Role Mac Address Priority Version State
----------------------------------------------------------
*1 Master 001c.23b1.e298 1 0 Ready
Switch2#show switch
Switch/Stack Mac Address : 001c.23b2.e295
H/W Current
Switch# Role Mac Address Priority Version State
----------------------------------------------------------
*1 Master 001c.23b2.e295 1 0 Ready
From above output , we may observe both individual switches are acting as Master with priority 1.
After stacking the switch which has the highest priority will be the "Master" and the other will be "Member" of the stack. The Master switch is responsible for updating the configurations to other switches.
Hence before connecting the stack cables , decide which switch has to be the master and change the priority. In our example , Switch1 will be the Master. Change the switch priority to the highest value i.e, 15 .
Switch2 # config terminal
Switch2(config)# switch 1 priority 15
Changing the Switch Priority of Switch Number 1 to 15
Do you want to continue?[confirm]
New Priority has been set successfully
Switch1#show sw
Switch/Stack Mac Address : 001c.23b1.e298
H/W Current
Switch# Role Mac Address Priority Version State
----------------------------------------------------------
*1 Master 001c.23b1.e298 15 0 Ready
Connect the Stack cables now . Important Note - The stack cables should be connected in crisscross manner i.e, stack port 1 of Switch1 to the 2nd stack port of Switch2 and vice-versa to form a ring. Please note only one cable is enough for stacking which would still work with half ring speed. However for cable redundancy and optimal ring speed usage , 2nd stack cable should also be used.
We assume now you have connected the cables now . If not please connect and then proceed with the below steps.
After connecting the cables , reload the switches. Once both switches are booted up , you should see a output as below with Switch1 elected as Master and Switch2 as the Member as Switch1 priority is higher.
Switch1#show sw
Switch/Stack Mac Address : 001c.23b1.e298
H/W Current
Switch# Role Mac Address Priority Version State
----------------------------------------------------------
*1 Master 001c.23b1.e298 15 0 Ready
2 Member 001c.23b2.e295 1 0 Ready
To view the stack port and neighbor switch connection status -
Switch1# show switch detail
Switch/Stack Mac Address : 001c.23b1.e298
H/W Current
Switch# Role Mac Address Priority Version State
----------------------------------------------------------
*1 Master 001c.23b1.e298 15 0 Ready
2 Member 001c.23b2.e295 1 0 Ready
Stack Port Status Neighbors
Switch# Port 1 Port 2 Port 1 Port 2
--------------------------------------------------------
1 Ok Ok 2 2
2 Ok Ok 1 1
Note - If you are not observing the second switch in the display , then there may be a requirement to "manually provision" the switch as described in the procedure below on Switch1.
Switch1 # config terminal
Switch1(config)# switch 2 provision ws-c3750-48ts
Switch1(config)# ^Z
Switch1 # show switch
Switch/Stack Mac Address : 001c.23b1.e298
H/W Current
Switch# Role Mac Address Priority Version State
----------------------------------------------------------
*1 Master 001c.23b1.e298 15 0 Ready
2 Member 0000.0000.0000 0 0 Provisioned
Now reload the switches , after which you should be seeing both the switches in "Ready" state.
Now that you have stacked the switches , you will notice all the ports of both switches may be managed through the Master switch. If you execute "show run" , you will notice ports of both switches are displayed and hence treated as one logical unit.
Now lets reboot the master switch and observe the status change
Switch/Stack Mac Address : 001c.23b2.e295
H/W Current
Switch# Role Mac Address Priority Version State
----------------------------------------------------------
1 Member 0000.0000.0000 0 0 Removed
*2 Master 001c.23b2.e295 1 0 Ready
Switch1#
Switch1#show sw
Switch/Stack Mac Address : 001c.23b2.e295
H/W Current
Switch# Role Mac Address Priority Version State
----------------------------------------------------------
1 Member 001c.23b1.e298 15 0 Progressing
*2 Master 001c.23b2.e295 1 0 Ready
Switch1#show sw
Switch/Stack Mac Address : 001c.23b2.e295
H/W Current
Switch# Role Mac Address Priority Version State
----------------------------------------------------------
1 Member 001c.23b1.e298 15 0 Initializing
*2 Master 001c.23b2.e295 1 0 Ready
Switch1 boot up is completed now . You will notice Switch2 is "elected" as Master which confirms you have successfully stacked the switches. Repeat this procedure by rebooting Switch2 also.
Switch1#show sw
Switch/Stack Mac Address : 001c.23b2.e295
H/W Current
Switch# Role Mac Address Priority Version State
----------------------------------------------------------
1 Member 001c.23b1.e298 15 0 Ready
*2 Master 001c.23b2.e295 1 0 Ready
Some of other useful switch stack commands for monitoring the performance and their output are as below
Switch1# show switch neighbors
Switch # Port 1 Port 2
-------- ------ ------
1 2 2
2 1 1
Switch1#show switch stack-ports
Switch # Port 1 Port 2
-------- ------ ------
1 Ok Ok
2 Ok Ok
Switch1#show platform stack manager all
Switch/Stack Mac Address : 001c.23b1.e298
H/W Current
Switch# Role Mac Address Priority Version State
----------------------------------------------------------
*1 Master 001c.23b1.e298 15 0 Ready
2 Member 001c.23b2.e295 1 0 Ready
Stack Port Status Neighbors
Switch# Port 1 Port 2 Port 1 Port 2
--------------------------------------------------------
1 Ok Ok 2 2
2 Ok Ok 1 1
Stack Discovery Protocol View
==============================================================
Switch Active Role Current Sequence Dirty
Number State Number Bit
--------------------------------------------------------------------
1 TRUE Master Ready 115 FALSE
2 TRUE Member Ready 117 FALSE
Stack State Machine View
==============================================================
Switch Master/ Mac Address Version Current
Number Member (maj.min) State
-----------------------------------------------------------
1 Master 001c.23b1.e298 1.45 Ready
2 Member 001c.23b2.e295 1.45 Ready
Last Conflict Parameters
Switch Master/ Cfgd Default Image H/W # of Mac Address
Number Member Prio Config Type Prio Members
-----------------------------------------------------------------------
1 Master 15 No 6 2 0 001c.23b1.e298
Stack Discovery Protocol Counters
Messages Sent Messages Recvd
UP DOWN UP DOWN
--------------------------------------------------------
*1: 0000001121 0000000885 0000000115 0000000116
2: 0000000117 0000000117 0000000859 0000000858
3: 0000000000 0000000000 0000000000 0000000000
4: 0000000000 0000000000 0000000000 0000000000
5: 0000000000 0000000000 0000000000 0000000000
6: 0000000000 0000000000 0000000000 0000000000
7: 0000000000 0000000000 0000000000 0000000000
8: 0000000000 0000000000 0000000000 0000000000
9: 0000000000 0000000000 0000000000 0000000000
Misc Counters
Counter Up Down
---------------------------------------------------
Wrong Ver Number: Send: 0000000000 0000000000
Wrong Ver Number: Recv: 0000000000 0000000000
Missed Messages: 0000000001 0000000000
Orphaned Messages 0000000000 0000000000
Suppressed Messages 0000000761 0000000762
No Available Messages 0000000096 0000000091
Link Present 0000000009 0000000003
Link Not Present 0000000009 0000000003
Link RxReset 0000000025 0000000013
Link Sync Stuck Resets 0000000026 0000000000
Duplicates 0000000741 0000000742
RAC Not OK Resets 0000000000
Switch# of last duplicate 0000000002
Sequence Number Failures 0000000000
RAC Not OK Resets 0000000000
Sync Not OK Resets 0000000070 0000003982
Switch# of last Failure: 256 Last Difference 0
Switch Number Conflicts 0
Stack Changes 18
Int Stack Link changes 0
Int Stack Link state 0x0
Reciprocal Efficiency Changes: Upgrade 0, Downgrade 0
Resource Counters
-------------------------------------------
Chunk Alloc's 0000000005
Chunk Free's 0000000004
Enqueue Failures: 0000000000
Null Queue Failures: 0000000000
Chunk Alloc Errors: 0000000000
Stack State Machine Counters
Messages Sent Messages Recvd
-------------------------------------------------
*1: 0000000000 0000000000
2: 0000000005 0000000005
3: 0000000000 0000000000
4: 0000000000 0000000000
5: 0000000000 0000000000
6: 0000000000 0000000000
7: 0000000000 0000000000
8: 0000000000 0000000000
9: 0000000000 0000000000
Switch1#show switch stack-ring speed
Stack Ring Speed : 32G
Stack Ring Configuration: Full
Stack Ring Protocol : StackWise
Switch1#show switch stack-ring activity
Sw Frames sent to stack ring (approximate)
------------------------------------------------
1 52147
2 18487
Total frames sent to stack ring : 70634
Note: these counts do not include frames sent to the ring
by certain output features, such as output SPAN and output
ACLs.
When any one stack cable is removed , you will notice stacking still works but at half the ring speed
Switch1#show switch stack-ports
Switch # Port 1 Port 2
-------- ------ ------
1 Down Ok
2 Ok Down
Switch1#show switch stack-ring speed
Stack Ring Speed : 16G
Stack Ring Configuration: Half
Stack Ring Protocol : StackWise
Hope this article helps to some who are new to stacking.