cdce — USB Communication Device Class Ethernet (CDC ECM/NCM) driver
Contents
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.
Debian May 21, 2018 CDCE(4)
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.
Diagnostics
cdce%d:nouniondescriptor 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:nodatainterfacecdce%d:couldnotreadendpointdescriptorcdce%d:unexpectedendpointcdce%d:couldnotfinddatabulkin/out For a manually added USB vendor/product, these errors indicate
that the bridge is not compatible with the driver.
cdce%d:watchdogtimeout 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:nomemoryforrxlist--packetdropped! Memory allocation through MGETHDR or MCLGET failed, the
system is running low on mbufs.
cdce%d:abort/closerx/txpipefailedcdce%d:rx/txlistinitfailedcdce%d:openrx/txpipefailedcdce%d:usberroronrx/txHardware
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
History
The cdce device driver first appeared in OpenBSD 3.6, NetBSD 3.0 and FreeBSD 6.0.
Name
cdce — USB Communication Device Class Ethernet (CDC ECM/NCM) driver
See Also
arp(4), cdceem(4), intro(4), ipheth(4), netintro(4), urndis(4), usb(4), ifconfig(8) UniversalSerialBusClassDefinitionsforCommunicationDevices, http://www.usb.org/developers/devclass_docs/usbcdc11.pdf. DatasheetProlificPL-2501Host-to-HostBridge/NetworkController, http://tech.prolific.com.tw/visitor/fcabdl.asp?fid=20679530.
Synopsis
To compile this driver into the kernel, place the following lines in your kernel configuration file:
deviceuhcideviceohcideviceusbdevicemiibusdeviceuetherdevicecdce
Alternatively, to load the driver as a module at boot time, place the following line in loader.conf(5):
if_cdce_load="YES"
