The Unifi LTE Pro* (AD) simply connects to any Unifi switch port as an LTE failover, so there is no need to pull a LAN cable from the WAN port to the Unifi LTE Pro if there is a LAN port nearby.
How does the Unifi LTE Pro work?
The Unifi LTE Pro creates a VLAN that tunnels the network traffic to the Unifi gateway in the event of a main line failure. It thus pulls a virtual LAN cable through the existing infrastructure.
Unfortunately, the Unifi LTE Pro can actually only be used as a failover; permanent use as a normal Internet connection or for load balancing is not possible. In addition, Unifi does not currently offer a 5G-capable device. Two reasons to choose another 5G / LTE router!
First of all, the purpose (failover / load balancing) and the bandwidth should be considered. For example, if you want a gigabit connection through a VLAN tunnel, the network infrastructure should be implemented over 10Gbit. Otherwise, a download can load the network to such an extent that problems occur. For a simple LTE / 5G failover, you can accept a reduced speed.
Connect 5G / LTE routers like the Unifi Pro LTE to the UDM
To connect a third party LTE / 5G router to the WAN2 port of the UDM Pro we create a “VLAN only” which is tagged to the switch port the router is connected to. On a switch near the UDM or on the switch of the UDM Pro itself we also tag a port with this VLAN. From there we connect the port with a LAN cable to the WAN2 port of the UDM.
WAN through VLAN tunneling
To realize our plan, we have to create a VLAN Only Network. This can be done under the old interface under “Settings” -> “Networks” -> “Create new network”.
We name the network e.g. “WAN1” and select the option “VLAN only” at “Usage” and assign a free VLAN tag. Now we save and if desired we can switch back to the new web interface.
On the switch to which the router / WAN is to be connected, the network “WAN” just created and the option “Port isolation” must now be selected for this port.
On a switch that is close to the Unifi gateway (Unifi Dream Machine Pro) we set the same options: Network “WAN” and Port Isolation. From this port we run a LAN cable into the WAN port of the router. Of course, you can also directly select the port on the Unifi Dream Machine, but the internal switch of the UDM is only connected with 1Gbit, with faster Internet connections this limitation quickly becomes a bottleneck.
It requires one more step and one more switch port than the Unifi LTE Pro, but it gives us the freedom to tunnel any Internet connection through the existing infrastructure and power the router, if supported, via Poe.