Router Mikrotik: using an LTE smartphone instead of a 4G/3G modem

April

2023

Router Mikrotik: using an LTE smartphone instead of a 4G/3G modem

управление

20 April 2023 14:59

Unlike numerous guides on how to set up a 3G modem with a Mikrotik router, this article examines the case where an LTE smartphone is used in USB modem mode instead of a 4G/3G modem.

Introduction

Traditionally, in Wi-Fi routers are connected to the Internet via cable. But the wired, fixed Internet is not always there, not in all apartments. Then they use mobile Internet using a USB modem for the cellular function of the 4G/LTE standard (via operators).

Since there were no external USB modem among relatives, I decided to use a regular 4G smartphone in the USB modem mode to enter the Internet. The router performs the function of DHCP, NAT, firewall to distribute the Internet to a local network, both via Wi-Fi and cable.

Advantages of this solution:

It’s easier to get a smartphone than a USB modem, it is always with me. In addition, the price of an inexpensive smartphone is often lower than that of 4G/3G modem.
On the main SIM-card of tele2 with an archival tariff, the Internet distribution is allowed, with a large amount of unused traffic.
Mikrotik routers require significantly fewer configuration steps for smartphones in USB modem mode than for external modems. Specifically, AT commands and initialization strings are not required.
After using the phone, the entire design can be disassembled and the phone is used for its intended purpose - for calls and the Internet.

Any smartphone with Android 6.0 or higher can be used as an LTE smartphone. A USB-A to micro USB cable or a USB-A to USB Type-C cable is required.

Settings LTE smartphone

Serve for a router
Connect a smartphone to a USB cable router
In the Android menu, go to the modem mode - turn on the USB modem switch.

Mikrotik router setting up for use with LTE Smartphone

First you need to find out the APN Internet for your mobile operator (you can see in the smartphone in the settings

Network and Internet
Mobile network
Additional settings
Access points (APN)
Click by name APN
APN - see value.

Option 1. Configuration using Terminal commands

Connect your smartphone to the USB port of the Mikirotik router and enable modem mode in its settings (Settings - More - Modem Mode - USB Modem - switch to ON).

In the Mikrotik Terminal, run the following commands:

/interface lte apn
set [ find default=yes ] apn=internet.tele2.ru name=tele2

Where in APN, enter the string for your mobile operator.

/interface list member
add interface=lte1 list=WAN comment="LTE USB phone"

We've added the lte1 interface to the WAN list.
DNS, NAT, and firewall settings are not required, as some settings are taken from the smartphone, while others are from the default Mikrotik configuration.

Option 2. Setup via the web interface

0) Connect your smartphone to the Mikirotik router's USB port and enable modem mode in its settings (Settings - More - Modem Mode - USB Modem - switch to ON).
1) Using a web browser, log in to the router's control panel.
Typically, the router's address is 192.168.88.1, but it can be different:

http://192.168.88.1

2) Configuring the settings

"Interfaces" menu
"LTE" tab
"LTE APNs" button
"tele2" string - click on the name
Edit the APN string From "internet" to "internet.tele2.ru" (you can find out the exact APN settings in your smartphone's menu or from your provider)
"Interface List" tab

"Add New" button

List - WAN, Interface - Lte1

You can add a comment in the field below.
Click OK
New line after adding.

3) Checking - ping and whoer.to:

Tools - Ping

Select the interface through which the check will be performed - Lte1

Click the Start button
You can see that all packets are passing through and are not lost (0% loss)

Checking the external IP address of a website on the internet https://whoer.to

Option 3: Configuring Mikrotik for an LTE smartphone using WinBox

Connect your smartphone to the USB port of the Mikrotik router and enable tethering mode in its settings (Settings - More - Tethering Mode - USB Modem - switch to ON).

Launch WinBox and connect to the router.

Interfaces -> LTE

LTE APNs

LTE APN "tele2"

Interfaces - Interface List

Add Interface List Member

Add Comment

User Experience and Conclusion

The internet connection speed was 20-25 Mbps.
The smartphone charges via a USB cable.
Internet setup via a smartphone is available on Mikrotik routers with a USB port (for example, the inexpensive RB951Ui-2HnD model).
Since the Mikrotik router's acceptable power supply voltage is 12 to 24 volts, it can be used in a car.
Any smartphone is suitable for this setup, including those with a broken display, unwanted devices, etc.
Instructions for configuring a backup channel via 4G in the event of an internet service provider (ISP) outage can be found online. In this case, this simple and accessible instruction may be useful as part of a more complex task – providing a backup internet connection for a LAN.

Last edited: May 31, 2024 (added clarification that before setting up the Mikrotik router, you need to connect your smartphone to it via a USB cable and enable "USB modem mode" in the settings, as otherwise the "LTE1" interface will not be visible; the website whoer.net was replaced with whoer.to).

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