Why Cisco 1941 does not receive IP via DHCP on the sub-interface?

Question

DHCP

Good afternoon, colleagues!
I have such a thing. There is a Teltonika RUT950 LTE router. In the role of a network bridge, it must transmit the IP received from the telecom operator to the connected device, in this case, the Cisco 1941 router. The physical interface normally receives IP, but the trouble with the subinterface is that it does not want to receive an IP address via DHCP. In the LTE settings of the router, I tried to set the VLAN and experimented with different settings, but nothing worked. Maybe someone faced with a similar case?

Answer 1

And why do you need a subinterface?
Connect to a physical one
Or are there not enough ports?
Then you get the trunk not from LTE, but from the switch.
Here in the switch and accept LTE with the necessary vlan
And already terminate this vlan on the corresponding sub-feature