CDCE(4)                 NetBSD Kernel Interfaces Manual                CDCE(4)

     cdce -- USB Communication Device Class Ethernet driver

     cdce*  at uhub? port ?

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

        Acer Labs USB 2.0 Data Link
        Anker A7611
        DIEWU USB-DW8152
        G.Mate YP3X00
        Motorola USBNET
        NetChip EthernetGadget
        Prolific PL-2501
        Realtek RTL8152B Ethernet controller
        Sharp Zaurus

     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 end-

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

     cdce%d: no union descriptor  The driver couldn't 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 descrip-

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

     arp(4), intro(4), netintro(4), usb(4), ifconfig(8)

     Universal Serial Bus Class Definitions for Communication Devices,

     Data sheet Prolific PL-2501 Host-to-Host Bridge/Network Controller,

     The cdce device driver first appeared in OpenBSD 3.6 and NetBSD 3.0.

     The cdce driver was written by Craig Boston <> based
     on the aue(4) driver written by Bill Paul <> and
     ported to OpenBSD by Daniel Hartmeier <>.

     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.

NetBSD 8.1                     December 19, 2016                    NetBSD 8.1

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