Shortly I will be deploying bunch of Brocade VDX switches in Logical Chassis Mode to replace the existing Cisco 3750’s.

I have a 40 GBPS QSFP+ breakout module.

To configure breakouts:

config t
hardware
connector 4/49
shut
exit
hardware
connector 4/49/1
sfp breakout

I later changed my mind and issued no sfp breakout command. The 40GB port went dead would not respond.

Here is what need to be done after issuing no spf breakout

Login to the LC primary switch
Go to the RBridge where you want to convert back the port
shutdown all the ISL ports that are connected to the LC
verify that all other switches show offline
run Copy default-config startup-config
reboot