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

     cdce -- USB Communication Device Class Ethernet device

     cdce*  at uhub?

     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   Dell Wireless 5530
	   +o   Dell Wireless 5540
	   +o   FRITZ!Box Fon ata 1020
	   +o   G.Mate YP3X00
	   +o   Lenovo Thinkpad USB 3.0 Ethernet	adapter	(FRU 03X6903)
	   +o   Motorola	USBNET
	   +o   NetChip EthernetGadget
	   +o   Prolific	PL-2501
	   +o   Sony Ericsson K610i
	   +o   Sony Ericsson F3705g
	   +o   Yota LU156
	   +o   ZTE MF831 LTE USB modem
	   +o   ZTE MF920V portable LTE WiFi router
	   +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).

     cdce0: extra ethernet descriptor  There is	more than one Ethernet de-

     cdce0: no data interface  The data	interface announced by the union de-
     scriptor cannot be	found.

     cdce0: no descriptor for interrupt	endpoint N
     cdce0: interface alternate	setting	N failed
     cdce0: no descriptor for bulk endpoint N
     cdce0: 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.

     cdce0: 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.

     cdce0: no memory for rx list -- packet dropped!  Memory allocation
     through MGETHDR or	MCLGET failed, the system is running low on mbufs.

     cdce0: abort/close	rx/tx/interrupt	pipe failed
     cdce0: rx/tx list init failed
     cdce0: open rx/tx/interrupt pipe failed
     cdce0: usb	error on rx/tx

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

     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.

FreeBSD	13.0			 May 12, 2020			  FreeBSD 13.0


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