QSFP+ breakout cables (MTP to LC) - How to extend

https://support.f5.com/kb/en-us/solutions/public/15000/000/sol15045.html

Well, you are required to use the F5 transceivers, but according to this SOL you can use a longer equivalent cable and still be supported. The caveat being F5 won't support the cable if there are connectivity issues so it will be a fine line to walk if you encounter any(most likely won't as light through glass is generally light through glass). I would double check with you local F5 rep to confirm the cable you plan to use. You will more likely want to find an 8 fiber MTP male to LC male fan cable like these, http://fibertronics-store.com/8-LC-Duplex-QSFP-MTP-MPO-Multimode-OM3-2mm-Breakout-Cable_c918.htm.