---
name: "umb"
section: "4"
platform: "openbsd"
package: "man"
version: "8.0-current-20261101"
release: "OpenBSD 8.0-current (2026-11-01)"
platforms: ["freebsd", "openbsd"]
url: "https://new.carta.tech/umb"
---

# umb(4)

USB Mobile Broadband Interface Model (MBIM)

## NAME

**umb** – USB Mobile Broadband Interface Model (MBIM)

## SYNOPSIS

**umb\*  at uhub?**

## DESCRIPTION

The **umb** driver provides support for USB MBIM devices.

MBIM devices establish connections via cellular networks such as GPRS, UMTS, and LTE. They appear as a regular point-to-point network interface, transporting raw IP frames. Once a connection is established, the device will automatically set an IP address and send out a nameserver proposal, which [resolvd(8)](/resolvd/8.md) can act on.

Required configuration parameters like PIN and APN have to be set with [ifconfig(8)](/ifconfig/8.md). Once the SIM card has been unlocked with the correct PIN, it will remain in this state until the MBIM device is power-cycled. In case the device is connected to an "always-on" USB port, it may be possible to connect to a provider without entering the PIN again even if the system was rebooted.

## HARDWARE

The following devices should work:

- Dell DW5821e

  - Ericsson H5321gw and N5321gw

  - Fibocom L831-EAU

  - Medion Mobile S4222 (MediaTek OEM)

  - Quectel EC25

  - Quectel EM060K

  - Quectel RM500Q

  - SIMCom SIM7600

  - SIMCom SIM8262E-M2

  - Sierra Wireless EM7345

  - Sierra Wireless EM7455

  - Sierra Wireless EM8805

  - Sierra Wireless MC8305

  ## EXAMPLES

The following [hostname.if(5)](/hostname.if/5.md) example configures umb0 to set the APN to “internet”, enabling data roaming, and obtaining an IP address using IPv6 stateless address autoconfiguration:

```
pin 1234
apn internet
inet6 autoconf
roaming
```

## SEE ALSO

[intro(4)](/intro/4.md), [netintro(4)](/netintro/4.md), [usb(4)](/usb/4.md), [hostname.if(5)](/hostname.if/5.md), [ifconfig(8)](/ifconfig/8.md), [route(8)](/route/8.md) *Universal Serial Bus Communications Class Subclass Specification for Mobile Broadband Interface Model*, https://www.usb.org/document-library/mobile-broadband-interface-model-v10-errata-1-and-adopters-agreement.

## CAVEATS

Devices which fail to provide a conforming MBIM implementation will probably be attached as some other driver, such as [umsm(4)](/umsm/4.md).