CDCE(4)                   OpenBSD Programmer's Manual                  CDCE(4)

NAME
     cdce - USB Communication Device Class Ethernet device

SYNOPSIS
     cdce*  at uhub?

DESCRIPTION
     The cdce driver provides support for USB Host-to-Host (aka USB-to-USB)
     bridges based on the USB Communication Device Class (CDC) and Ethernet
     subclass, including the following:

           o   Acer Labs USB 2.0 Data Link
           o   FRITZ!Box Fon ata 1020
           o   G.Mate YP3X00
           o   Motorola USBNET
           o   NetChip EthernetGadget
           o   Prolific PL-2501
           o   Sharp Zaurus
           o   Sony Ericsson K610i
           o   Zyxel P-971M

     The USB bridge appears as a regular network interface on both sides,
     transporting Ethernet frames.  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.  For
     more information on configuring this device, see ifconfig(8).

DIAGNOSTICS
     cdce%d: extra ethernet descriptor  There is more than one Ethernet de-
     scriptor.

     cdce%d: no data interface  The data interface announced by the union de-
     scriptor cannot be found.

     cdce%d: no descriptor for interrupt endpoint %d
     cdce%d: interface alternate setting %d failed
     cdce%d: no descriptor for bulk endpoint %d
     cdce%d: could not find data bulk in/out  For a manually added USB ven-
     dor/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/interrupt pipe failed
     cdce%d: rx/tx list init failed
     cdce%d: open rx/tx/interrupt pipe failed
     cdce%d: usb error on rx/tx

SEE ALSO
     arp(4), cdcef(4), intro(4), netintro(4), usb(4), hostname.if(5),
     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.

HISTORY
     The cdce device driver first appeared in OpenBSD 3.6.

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 port-
     ed 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.

OpenBSD 4.7                     March 14, 2008                               2
