added extra packages to custom image:
kmod-usb-net-qmi-wwan uqmi luci-proto-qmi kmod-usb-serial-option picocom nano mwan3 luci-app-mwan3 iptables-nft ip6tables-nft
I have set 2 QMI interfaces.
The 2 modems work properly as I see 2 interfaces active. Unfortunatelly I don't know how to set mwan3 loadbalance. When I do I speedtest the speed is almost the same between 1 interface active + 1 interface deactivated and 2 interfaces active. Any help?
In general, multi-wan configurations will only improve the speeds when you have several simultaneous connections, preferably between several clients and several servers. How are you performing your speed tests?
Load balancing means that some connections go over one WAN and some on the other. This increases overall speed if there are a number of users or multiple connections. The speed of one connection such as a file download or a simple speed test is the same since it all goes through only one modem.
thanks for the clarification. There is any solution to sum the connection speeds like splitting the traffic (of a single download or a single user or a single streaming) over two interfaces/modems? thanks in advance
There is only one solution, coming in two slightly different flavours. You need a well connected system on the internet to re-assemble your two wan connections. This can be either a paid service from your ISP or you doing this yourself on a server in some data centre (maybe there are also commercial VPN-like services providing this feature on your behalf).
Because most network protocols are not ready to have their traffic split between two paths. It's not something that can be magically created on one end, unless the other one and has support for it too.