CDCEEM(4)

NAME
cdceem - USB Communication Device Class Ethernet Emulation Model (CDC EEM) driver

SYNOPSIS
To compile this driver into the kernel, place the following lines in your kernel configuration file:

device uhci
device ohci
device usb
device miibus
device uether
device cdceem

Alternatively, to load the driver as a module at boot time, place the following line in loader.conf(5):

    if_cdceem_load="YES"

DESCRIPTION
The cdceem driver provides support for USB devices based on the USB Communication Device Class Ethernet Emulation Model (CDC EEM) specification.

The driver works on both host, and device-side; see usb_template(4) for details.

The USB device appears as a regular network interface on both sides, transporting Ethernet frames.

For more information on configuring this device, see ifconfig(8).

The cdceem driver does not support different media types or options.

SYSCTL VARIABLES
The following variables are available as both sysctl(8) variables and loader(8) tunables:

hw.usb.cdceem.debug
    Verbosity level for log messages from the cdceem driver. Set to 0 to disable logging or 1 to warn about potential problems. Larger values enable debugging output. Defaults to 1.

hw.usb.cdceem.send_echoes
    If set to 1, the driver will send an Echo EEM packet when the interface is brought up. While responding to Echo is mandatory, some devices cannot handle it. Only use for debugging. Defaults to 0.

hw.usb.cdceem.send_fake_crc
    If set to 1, the driver will use 0xdeadbeef as the CRC value for outgoing Data EEM packets. Only use for debugging. Defaults to 0.

SEE ALSO
arp(4), cdce(4), intro(4), ipheth(4), netintro(4), urndis(4), usb(4), usb_template(4), ifconfig(8) Universal Serial Bus Communications Class Subclass Specification for Ethernet Emulation Model Devices, https://usb.org/sites/default/files/CDC_EEM10.pdf.

HISTORY
The cdceem device driver first appeared in FreeBSD 12.1.

AUTHORS
The cdceem driver was written by Edward Tomasz Napierala <trasz@FreeBSD.org> under sponsorship from Hewlett Packard Enterprise.