Using 40G Stacking cables (MA-CBL-40G-50CM, -1M, -3M) as an uplink connection (not stacking)

[Ben74]

Hi,

I'm looking to connect an MS425 and an MS390 w/ a 2x 40G module together using the 40G QSFP ports. Both switches are in the same rack and I'd rather not purchase a 40G fiber transceiver if possible. I am not looking to stack the switches, only to uplink them together.

As the 40G staking cables are QSFP twinnex cables, will these cables work as 40G uplinks between switches, or is there some reason they'd be limited to only working on ports configured as stack ports?

[DarrenOC]

Hi @Ben74 , that part code is solely a stacking cable and can only be used for this purpose

https://meraki.cisco.com/lib/pdf/meraki_datasheet_sfp.pdf

[Bruce]

As @DarrenOC stated, its technically not supported, although to connect two devices that are next to each other with MA-QSFP-40G-SR-BD modules, which would be the cheapest, still seems an expensive approach. You have two options:

1. Go with the Meraki supported option and purchase the required transceivers
2. Use a third party option and hope it works (more often than not they do). In this case if you raise a support case and Meraki Support believe the transceiver is the issue they may ask you to swap to a supported transceiver before they assist further

[PhilipDAth]

I don't know the answer.

I think it should work.  They are just TwinAx cables after all.  They just happen to be 40Gbe TwinAx that's all.