Cisco Stackwise

Hi Rene,

“If the master fails, another member will become the new member.”

You mean Master?! :slight_smile:

Regards,

Scott

Oops…just fixed it :slight_smile: Thanks for letting me know Scott!

Hi Rene,
I have couple of questions here…
Consider a stack of 2 switches. Do We need to enable spanning tree on the stack for connecting other switches on this stack, in a redundant manner ?
Also How does the IOS upgrade happen on the member switches in stack? Would the upgrade on master take care the member switches too?

Hi
What is difference between stack and VSS? Both create one virtual switch which is combination of 2 or several switches!!!

Hi Sepideh,

Both have similarities. VSS is used on the 4500 and 6500 switches and can be used to combine two switches into a single virtual switch.

Stackwise is used on the smaller switches like the 3750.

Rene

Hi Ashok,

You don’t need STP for the connections between the switches in the stack, the stack is seen as one “logical” switch.

If you want to upgrade the IOS image then you should copy the image to the flash memory of all your switches, then configure the master switch to boot the new image and reload the switches. Cisco has a good document with some examples:

Rene

Hello Rene,

why we need to configure in switch 1 #switch 2 renumber 1 ?

what is mean by Provision state ?

when we are using “sh switch command” instead of showing" ready" it’s showing as" provision" could you please help me to resolve the issues ?

 

 

 

 

Hi Rene,

Thank you for this tutorial . I would like to know more on how to do the provisioning of the stack members and what are the proper procedures for removing stack. And also the differences (speeds, source stripping and destination stripping,etc…) between Stackwise and Stackwise plus.

 

Thank you.

 

Best Regards,

Ronie

Hmm I think it shows up as “provision” when the switch isn’t successfully added to the stack or when the stack cable is disconnected.

Renumbering can be used to change the interface numbers. Depending on the stack number you will have interface numbers like fa1/0/1 or fa2/0/1 or something.

@Ronie Cisco has a pretty good document that explains the differences between these:

 

Rene,

Hi. I think that there exact order of the stack member election might not be correct when compared to what is outlined at URL below.

 

 

Thomas

Hi Rene,

Can you advise if the following behaviour is normal

T1) 2 x 2960x stacked - show switch reflect 1 master and 1 member.

T2) stack cables are removed from both switches and a reboot is done

T3) both switches reflected themselves as Master and the other as member

T4) plug back stacking cables, but no re-election occur.

Both switch remain “split brain” thinking itself as the Master, even if the stack cable is reconnected back.

 

Is this behaviour normal or a bug ?
Is there anyway to force a re-election without rebooting the switch ?

 

Regards,
Alan

Hi Rene,

To add on to the previous post, i would like to highlight that

a) when the stacking cable is added back to connect the 2 switches together, each switch still think itself as Master and show the other switch as Member.
Each of the switch also show the other Member switch’s status as “Provisioned” instead of “Ready” - why doesn’t the status become “Ready” ?

in Switch A -> Switch A (Master/Ready), B (Member/Provisioned)
in Switch B -> Switch B (Master/Ready), A (Member/Provisioned)

 

b) I rebooted one of the switch (Switch B), and when it is backup, no election take place also. The status remain the same as above.
It is only when i rebooted both switch together, then the re-election process begin.

 

Why ? Is this normal ? Does that mean everything my stack cable is down, i would have to restart the whole stack ?!

 

Regards,
Alan

Hi Alan,

Hmm I think this is normal. When there is no cable, both switches will elect themselves as the master. There is no preemption so once a switch is master, it will remain master. After connecting the cable you would expect a re-election but I don’t think this occurs.

If you keep the cable connected and reboot the switches, then everything works fine?

Rene

Hi Rene,

First of all, your work is amazing, thank you very much!

I used Stackwise for a while in several branch office designs and I like the advantages about it.

some weeks ago I had a discussion with a consulting farm, they claim that Stackwise is still running spanning-tree on the switch backplane

and would not converge fast due to the spanning-tree. It seems odd to me and never heard about it.

Do you know if that is the case and have you ever seen some info about this?

 

Thanks a lot!

 

Hi Geert,

Glad to hear you like my work!

Spanning-tree doesn’t run on the stackwise backplane, not sure where they got that from :slight_smile: They use some proprietary mechanism to create a “bidirectional closed loop path” (that’s what Cisco calls it).

Rene

Quick question, how would I know what physical interface on stacked switches is on the CLI. If I have a stack of 9 switches, and my admin says unplug the cable to g3/0/20, what switch am I physically unplugging if I saw 9 switches stacked? Would I have to know the MAC of switch 3 and look at the sticker at the back of the switch?

Hi Seth,

Normally the stack members are numbered from 1 to 9. Here’s an example for two switches in a stack:

SW1#show ip interface brief | include Fast
FastEthernet1/0/1      unassigned      YES unset  down                  down    
FastEthernet1/0/2      unassigned      YES unset  down                  down    
FastEthernet1/0/3      unassigned      YES unset  down                  down    
FastEthernet1/0/4      unassigned      YES unset  down                  down    
[output omitted]    
FastEthernet2/0/1      unassigned      YES unset  down                  down    
FastEthernet2/0/2      unassigned      YES unset  down                  down    
FastEthernet2/0/3      unassigned      YES unset  down                  down    
FastEthernet2/0/4      unassigned      YES unset  down                  down    
[output omitted]

FastEthernet 1/x/x is SW1 and 2/x/x is SW2. In your case, it should be the third switch from the top.

Rene

So best practice is to have your master at the top of the stack and physically label each switch? I am only wondering this because we are supposed to cross the stackwise cable to each switch, like stack1 connector connects to stack2, the stack1 connectoe connects to stack2. So on and so forth until the last stack switch connects his stack1 connector to stack2 on the master. Maybe the IOS of the master knows that anything connecting to my stack1 slot will be g2/0/1 and anything connecting to my stack2 slot will be gX/0/1.

When a switch joins the stack then it will pick the lowest available member in the stack.

If you have 5 switches and you want to number them from top to bottom then it might be a good idea to configure them like this:

switch 1 priority 15
switch 2 priority 14
switch 3 priority 13
switch 4 priority 12
switch 5 priority 11

This ensures that the same switch is always elected as the master and that the interface numbers will match.

If needed, you can also rename them later:

switch 4 renumber 5

This will rename switch number 4 to 5.

Thank you for your input, it has helped a lot. I found this, http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3750e_3560e/hardware/installation/guide/hig/HIGOVERV.html#wp1125976
If you push the button on the front of the switch and select stack, it will tell you the member number and how many switches are in the stack. Neat!