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usbmodem

USB modem internet connection

ULARI has a fully functional USB host interface with two USB-A connectors and USB host stack is supported by Linux operating system. This means that we can connect almost any USB device (if it's drivers are supported by our Linux kernel) and use it with our hardware.

In this chapter we want to use a 3G or LTE modem to allow our station to access the internet via cellular network. After making a little research my choice was a Huawei E3372h-153 modem working in HILINK mode. HILINK mode is an important feature because it makes the modem report to operating system as a virtual network card. Earlier cellular modems were controlled by one or more serial interfaces, AT commands, PPP protocol, scripts, etc. and it was a lot more complicated. With HILINK mode, our modem acts as a router for our device, it evens assigns it a proper IP address and rest of network settings via DHCP protocol.

And what do we need to do? Well, we only need to plug the modem into USB port and a new network interface will appear:

As we can see on above picture, a new network interface is called enx0c5b8f279a64 and the name includes the hadware network address, according to a Linux naming sheme introduced in recent kernel versions (your interface name will be different as hardware network addresses should be unique for any manufactured network device). Assigned IP address is 192.168.8.100 which is a first free IP address from modem's DHCP pool.

We can also check the routing table to see if network traffic is routed via USB modem:

Only the first row is imporant in this case. We can see that all trafic (0.0.0.0) is routed via 192.168.8.1 which is an USB modem's IP address.

usbmodem.txt ยท Last modified: 2019/03/08 09:44 by sq3plx