The problem is that i am using RB912UAG-2HPnD with Sierra Wireless MC7710 (fw 3.05.23.02) inside vehicles. Unfortunately the RouterOS have a few implementation problems on this scenarios with mobility.
The first problem is that the LTE interface with the "Network Mode" setting on auto, it takes to many time to connect to a 3G network if the 4G network isn't available. Besides the time it takes to downgrade, when it does, it stays on that technology even if a better network is available again. The problem is that when the modem connects to GSM tech it says on it forever, it only upgrade again if i restart the LTE interface or power reset the modem.
This on a scenario where the Mikrotik is inside a vehicle, with constant change of the access technologies, doesn't work as expected.
The other problem that i am facing is with the GPS on the MC77110. After some time the GPS stalls and it will only work again if i power reset the modem. This is again another problem because when i reset the modem it takes a few seconds to come back again plus if there is no 4G access it will wait to timeout to connect to 3g, this takes around 30+ seconds where the users lose connectivity.
The question is, can the LTE Network Mode selection be improved, so the downgrades can be more transparent and support access tech upgrades when there are better technology available?
Also is there any way to deactivate the GSM mode? i am using a script that from time to time it checks if the LTE interface is on GSM and if it is the script restart the LTE interface, it works but it is not an elegant solution.