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 cdceAlternatively, to load the driver as a module at boot time, place the following line in loader.conf(5):
if_cdce_load="YES"
DESCRIPTION
Thecdce 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
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), 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.