Hi all,

after my PoC for a mobile AP using the LTAPmini in a very specific way proved to be a not so good concept, I now want to make use of the little box to:
a) increase WiFi coverage in my garden
b) use the LTE as the backup/failover to by DSL-based WAN

The configuration plan is to create a bridge, adding the wifi- and eth-interface and the vlan config, and to join capsman. That is basically the same configuration I have on my wAP and cAP. Where I'm stuck is the LTE part and I hope someone can give me a direction here. On my central Router (RB3011) I have a link to a fritzbox that provides the WAN-Connection. Similar to that, I now want to use "LTE-Device" to be able to switch routing on the RB3011 from the DSL-WAN (Fritzbox) to LTE. My thoughts: Create a second bridge, let's name it bridgeLTE, and add the LTE interface. Configure VLAN99 (Mgmgt-VLan) and VLAN88 (coming to that shortly) for this bridge and assign a IP_adress for that bridge in the VLAN88. On my central router (RB3011) I also would add a new VLAN88 which has the sole purpose to connect the LTAP/BridgeLTE with the RB3011-Bridge where the routing is done. I believe I then should be able to configure 2 routes (probably as failover) on the RB3011 to either route the traffic to the IP of the Fritzbox linked directly on ether1 or to the IP of the bridgeLTE in VLAN88.

My understanding is that when using the LTE-Modem in the LTAPmini, it receives an IP etc. from the LTE-Provider and this can be accessed via the routing on the bridgeLTE.

Did I miss something or is this a way to go?

Cheers
plani

What you describe is almost the way to go, except that you cannot make an LTE interface a member port of a bridge. So you have two options, set the LtAP as a router with NAT, and set its private IP in VLAN 88 as a gateway at the 3011, or you can indicate the VLAN 88 interface on the LTE as the passthrough-interface on an /interface lte apn row, and attach a DHCP client to the VLAN 88 interface at the 3011 to have the IP address from the LTE at the 3011.

Neither of these interferes with using the LtAP as a cAP in parallel.

Thanks Sindy for the reply. I've not answered yet, because I was hoping the SIM-Card would arrive for a first test, which is not the case yet. So let me recap in my words what @sindy said to see if I understood correct:
a) Setup the LtAP as Router with the LTE "Connecting locally" and routing on the LtAP, which probably would not be the preferred way looking at the plan to run a failover-routing on the 3011.
b) Set LTE to passthrough, meaning that the LTE "connects" or "forwards" everything to another interface which then can directly be accessed from the RB3011 and hence simplify the failover later.

Now, what I don't get, what do you mean with " indicate the VLAN 88 interface on the LTE as the passthrough-interface". For the WiFI part I would create a bridge, with a trunked ether1 port and corresponding VLANs on wlan1. I tried to: and can only choose: as interface bound to that vlan-interface. Or would I add ether1 as trunk.port to the bridge and as VLAN-Interface to VLAN88 for the passthrough? Sorry, I must have a mistake in my logic and can't find it. How would I access the passthrough then? And I assume in a passthrough-configuration/-setting I would need to do the NAT etc. on the RB3011, right?

Sorry if my questions sound stupid, but I somehow can't get my head around this properly.

Sorry if my questions sound stupid

Stupid questions are actually rare. Stupid answers are much more common.

ad a), for the failover at the 3011 it makes no difference whether the second WAN interface of the 3011 gets its IP configuration directly from the LTE modem (using the passthrough method) or whether it gets it from the LTE router, which in turn gets another address from the LTE modem. The only difference is that there is the additional interconnection subnet, but that is not in conflict with anything, it's the same as if that WAN was connected to an ADSL modem in router mode, except that you don't need a double NAT as you can set a route to the subnets served by the 3011 at the LTE modem, which is not always possible on ADSL modems.

ad b), since you need wlan1 and ether1 to be bridged together, you have to attach all /interface vlan to the bridge, not to ether1.

So it would look like this:

/interface bridge
add name=bridge1

/interface bridge port
add bridge=bridge1 interface=ether1
(the wireless interfaces will be added dynamically by CAPsMAN)

/interface vlan
add interface=bridge vlan-id=88 name=bridge1.88

/interface lte apn
add add-default-route=no apn=internet name=passthrough use-peer-dns=no passthrough-interface=bridge1.88

/interface lte set [find] apn-profiles=passthrough

I apologize in advance if VLAN interface cannot be used for passthrough, I haven't tested this setup practically yet.

Regarding the bridge, this post may help clarify some confusion.

@plani: Did you succeed? I'm also having the same use case. I assume you want to use the internal LTE of the LtAP device?
I'm new and struggling to understand all this: you have to somehow put the LTE modem into a separate network of its own (so into a VLAN) just so you can create the routes and do the advanced routing failover?

@plani: Did you succeed?

Sorry @farshield I missed your post. The answer will not be of much help: No, I didn't because I went down another path. As the LTE-modem in my LtAP seemed to be defect, I had a weak moment and bought an SXT-LTE kit which I mounted on my roof. This is then connected to a dedicated port on my central router and......and hopefully by years end I will be able to configure the failover.