Configuring OpenWrt with mwan3

Hi everyone,

So I'm running OpenWRT on a D-Link DWR-921
I have the LTE interface setup as per the instructions here:

To enable the wireless network connectivity the following UCI command shall be executed once:

uci set network.wwan=interface
uci set network.wwan.proto='wwan'
uci set network.wwan.apn='<your provider apn>'
uci set network.wwan.pincode='<your sim pin code>'
uci set network.wwan.auto='0'
uci commit network
please replace the placeholder with your real data.

uci set firewall.@zone[1].network='wan wwan wan6'
uci commit firewall
and at the next reboot you can enable/disable the connection using the following commands:

ifup wwan / ifdown wwan

This has been working perfectly for me for sometime. Now I have moved location to an apartment that has a cable router. I would like to configure my OpenWrt router to take advantage of load balancing over the LTE connection and the WAN port connected to my cable router.

I installed mwan3 and attempted to configure this, but i'm struggling to actually get this working. Any help or advice would be gratefully appreciated as I cant seem to find a clear document that explains this.

Kind regards

Read https://openwrt.org/docs/guide-user/network/wan/multiwan/mwan3

Yeah I read through this but to be quite honest it really doesn't make much sense...I tried to create the second wan interface though a vlan, but the documentation just isn't that clear.

Documentation is very good. Please, ask basic questions. You don't need vlan, because you already had two independent interfaces. Check configuration file /etc/config/mwan3, let's start with it.

Ok, so lets go back to basics here...So in order to ensure that my interfaces are actually working, I first removed mwan3.

I then connected to my router and tested the first WAN interface.

ping -c 1 -I wwan0 www.yahoo.com
PING www.yahoo.com (87.248.98.7): 56 data bytes
64 bytes from 87.248.98.7: seq=0 ttl=49 time=81.134 ms

Ok so we are working on this interface.

I think my problem is that the second WAN interface is not coming up at all. So I guess my first question is, how do I get the WAN port working on the router?

What interface is not working, wired or LTE?

Its the Wired WAN interface, the router has 1 Ethernet WAN port and 1 - 4 Lan ports. My idea was to connect the WAN port via Ethernet to my cable router...

OK, so what is the problem? Do you understand, that 'second' router makes another NAT?

yes i understand that, but the actual WAN port does not come up at all...

OK, please, connect router to cable router, and give output of:
ifconfig
Give also contents of /etc/config/network