3850 switch stack ports

[Joel Strawn]

I have 2 cisco 3850's that I am trying to put into a stack.  I have provisioned the 2 switches, set stack numbers on them, but the stack ports never come up, they are always in DOWN status.  What do I need to do??  I am used to 3750's and have no issues making them a stack..  

These are the first 3850's I have gotten in.  They are 48 port T switches.  I only have 2 of them, and stack cables go from port 1 (top switch) - port 2 (bottom switch)  and  port 2 (top switch) - port 1 (bottom switch).

[jhager001]

You shouldn't have to do anything special, just like the 3750's when they go through the stack master election it does everything itself, have you tried to restart the entire stack after assembling the cables to possibly get different results? I noticed the other day when I was stacking my 3850's that when I reset just one switch in the stack it took an unforgivable amount of time to rejoin the stack and was not seen. When I restarted the entire stack (because i'm impatient and these things take 7 minutes to boot up....) it finally discovered and worked properly.

You could try to stack slot 1 to stack slot 2 on the same switch to test the cable, and/or faulty ports?

'show switch stack-ports summary'

[Joel Strawn]

when I do that this is what I get, they are not working on either switch...  I just dont get it...

LE-Management#sh switch stack-ports summ

Sw#/Port#  Port Status  Neighbor  Cable Length   Link OK   Link Active   Sync OK   #Changes to LinkOK  In           Loopback
----------------------------------------------------------------------------------------------------------          ---------
1/1        DOWN         NONE      Unknown        Yes       No            Yes       1                   No           
1/2        DOWN         NONE      Unknown        Yes       No            Yes       1                   No         

[jhager001]

Can you stack the switches together and do a 'show switch' and 'show switch stack-ports summary' for me?

If this is a production switch or business critical, is it possible to schedule an outage window and restart the stack entirely after hours? It appears to be failing in a stack master election problem. be sure to set priorities on each switch to keep the primary one as master.

[Joel Strawn]

I did that in the comment above... and I have it on one switch with the stack cabled connected to the same switch...  If I have 2 of them I get the same statements, and it never actually sees the second switch in the stack.

[jhager001]

Hmm... have you tried to provision a new switch to the running config and then restart slot 2? Not sure why its not seeing the cables though, I don't have any 3850's that I can play with at the moment to test. If that doesn't work i'm thinking the only other fix action would be to connect them up and restart them together.

Try this before that last resort

"

conf t

!

switch 2 provision ws-c3850-48p

!

end

!

reload slot 2

"
 

[Joel Strawn]

its actually a ws-c3850-48t and when I try and reload slot 2 it says it is not present...  Hence my quandry...

[Surjeet Singh]

Hi, I am facing similer issue, does any one fix this ? If yes, than how ?

[benjaminbintener]

Could happen if you plug the power stack cables instead of data stack cables...

hope i'm not alone! :)

[lrebut001]

Hi Guys,

It just happened to me, and the reason was I had the stackwise cables upside down...

before :

Sw#/Port# Port Status Neighbor Cable Length Link OK Link Active Sync OK #Changes to LinkOK In Loopback
-------------------------------------------------------------------------------------------------------------------
1/1 DOWN NONE No cable No No Yes 0 Yes
1/2 DOWN NONE No cable No No Yes 0 Yes

After plugging them with the Cisco logo ON TOP

Sw#/Port# Port Status Neighbor Cable Length Link OK Link Active Sync OK #Changes to LinkOK In Loopback
-------------------------------------------------------------------------------------------------------------------
1/1 DOWN NONE 50cm Yes No Yes 0 No
1/2 DOWN NONE 50cm Yes No Yes 0 No

and the stack formed...