CDCE(4)                FreeBSD Kernel Interfaces Manual                CDCE(4)

NAME
     cdce - USB Communication Device Class Ethernet (CDC ECM/NCM) 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 cdce

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

           if_cdce_load="YES"

DESCRIPTION
     The cdce driver provides support for USB Host-to-Host (aka USB-to-USB)
     and USB-to-Ethernet bridges based on the USB Communication Device Class
     Ethernet Control Model (CDC ECM) and Network Control Model (CDC NCM)
     specifications.  It also provides device-side CDC ECM support.

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

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

     USB 1.x bridges support speeds of up to 12Mbps, and USB 2.0 speeds of up
     to 480Mbps.

     Packets are received and transmitted over separate USB bulk transfer
     endpoints.

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

HARDWARE
     The following devices are supported by the cdce driver:

     •   Prolific PL-2501 Host-to-Host Bridge Controller
     •   Sharp Zaurus PDA
     •   Terayon TJ-715 DOCSIS Cable Modem
     •   Realtek RTL8156 USB GBE/2.5G Ethernet Family Controller
     •   Planex USB-LAN2500R

DIAGNOSTICS
     cdce%d: no union descriptor  The driver could not fetch an interface
     descriptor from the USB device.  For a manually added USB vendor/product,
     the CDCE_NO_UNION flag can be tried to work around the missing
     descriptor.

     cdce%d: no data interface
     cdce%d: could not read endpoint descriptor
     cdce%d: unexpected endpoint
     cdce%d: could not find data bulk in/out  For a manually added USB
     vendor/product, these errors indicate that the bridge is not compatible
     with the driver.

     cdce%d: watchdog timeout  A packet was queued for transmission and a
     transmit command was issued, however the device failed to acknowledge the
     transmission before a timeout expired.

     cdce%d: no memory for rx list -- packet dropped!  Memory allocation
     through MGETHDR or MCLGET failed, the system is running low on mbufs.

     cdce%d: abort/close rx/tx pipe failed
     cdce%d: rx/tx list init failed
     cdce%d: open rx/tx pipe failed
     cdce%d: usb error on rx/tx

SEE ALSO
     arp(4), cdceem(4), intro(4), ipheth(4), netintro(4), urndis(4), usb(4),
     ifconfig(8)

     Universal Serial Bus Class Definitions for Communication Devices,
     http://www.usb.org/developers/devclass_docs/usbcdc11.pdf.

     Data sheet Prolific PL-2501 Host-to-Host Bridge/Network Controller,
     http://tech.prolific.com.tw/visitor/fcabdl.asp?fid=20679530.

HISTORY
     The cdce device driver first appeared in OpenBSD 3.6, NetBSD 3.0 and
     FreeBSD 6.0.

AUTHORS
     The cdce driver was written by Craig Boston <craig@tobuj.gank.org> based
     on the aue(4) driver written by Bill Paul <wpaul@windriver.com> and
     ported to OpenBSD by Daniel Hartmeier <dhartmei@openbsd.org>.

CAVEATS
     Many USB devices notoriously fail to report their class and interfaces
     correctly.  Undetected products might work flawlessly when their vendor
     and product IDs are added to the driver manually.

FreeBSD 13.1-RELEASE-p6          July 10, 2019         FreeBSD 13.1-RELEASE-p6