Thats correct. Only the current master has a white light. The warm spare is orange.   The switches have a white light while the warm spare is powered off but shortly after powering on the warm spare the switches turn orange, even though the master doesnt change. the warm spare doesnt become master. theres no indication of a dual-master scenario.   Sometimes the switches go to white but wont stay that way, they'll go back to orange after a short time. ... View more

Hi PhilipDAth,   Good point, I should have elaborated on how the two MX's are connected.   I have two MS225 switches. Each MX64 has a trunk to each switch.   +-----+ | | | cpe | | | +--+--+ disconnected | + | | | | | | +-+------+ | | | | | MX64 | | | master | | +-+------+--------------+ +-+------+ | | | | | | | MX64 | | | | w/spare| | +--------------+------+-+ | | | | | | | | | | | | +----+----------+-+ +-+----------+----+ |MS225-48 | |MS225-48 | | | | | +-------+---------+ +-------+---------+ | | | | | | | | +---+--+ +--+---+ | | | | | MR42 | | MR42 | | | | | +------+ +------+ Firmware versions are consistent across all devices. The MX64s are running 12.26 and the MS225s are running 9.32. Config is 'up to date'.   There's a 4G usb dongle on-site that was used while we waited for the wired internet to be delivered. At the moment its only got a prepaid sim which is out of credit so no data service available.   The second internet isnt the concern, the concern is the behaviour when the spare doesnt have internet. I can reproduce the problem in a lab at head office which has the exact same hardware. As soon as I pull the internet from the warm spare the network falls to pieces and I dont understand why.   ... View more