Cisco 3850 Stackwise Multiple Floor's Fiber

[Bernard23]

Hello,

I'm relatively new to the forums, so I hope this question is not misplaced.  I'm trying to add two switches to our current stack, and I'm not sure if it's even possible.  We have six switches in a stack on the 8th floor; the two additional switches reside on the 9th floor.  We have Fiber cables running from the 8th to 9th floor, however I cannot figure out how to make them all one stack.  The stackwise cable's are not nearly long enough; so I'm wondering if this is possible with the fiber connection, or if there is another work around.  

This may be a silly question, but I figured I would ask; it seems like a rather common scenerio for companies in office buildings.  Any solution or workaround guidance would be greatly appreciated.

Regards,

Bernard.

[chrihussey · Accepted solution]

Hello,

You will not be able to stack the switches between floors. It cannot be done with the fiber but only with the stack cables. Your best course of action may be to stack the switches in their respective closets and then create a trunked port channel between the two locations for connectivity and redundancy.

Hope this makes sense and helps.

[Bernard23]

Thanks for the replies!

[Mark Malone]

Hi
Short answer is you cant stack with standard fibre cables you must use stack cables but you could stack the 2 9th floor switches use a port-channel each of the switches to separate switches in the 8th floor stack linking them up with resiliency and giving them good throughput to the stack , longest stack cables are 3meters I think on 38s and the most you can stack is 8 but personally I wouldn't stack past 6 anyway , seen memory issues drop whole stacks of 8 before

[Joseph W. Doherty]

As others have already noted, you cannot stack a 3850 beyond the physical distance supported by the stack cables (BTW, there are optional longer cables, for top to bottom of stack, or between stack cabinets, but not for between floors).

Also BTW, Cisco's VSS would allow a two unit stack on fiber cables, but that's not supported by the 3850 (as far as I know).

Also BTW, other vendors do support much longer ranged switch stacks, so it might eventually become a Cisco feature in some later Cisco switch series.