Proper way of enabling MMS

MMS (multi-master-multi-sync) allows multiple AP clusters in the same area to use the same frequency band by synchronize the frequency hopping and data transmission. 

For MMS to work, all radio devices sharing the same frequency band need to be in sync by enabling MMS.

In the MMS configuration, there is no such option as "enabling sync", you would choose "external" or "generate".

For an AP that would use external GPS for the sync, choose "external". For an AP that would provide internally generated sync, you choose "generate".

What if the AP is taking the sync from the EP in a dual radio back-to-back relay scenario? You choose "external".

What about the EP, which take the sync from the AP it is attached to, you use "generate"! Keep in mind, that by choosing "generate", you get the EP into sync mode. otherwise, the EP will NOT be operating in sync mode and MMS will NOT work!