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UDBP(4) 		     Kernel Interfaces Manual			 UDBP(4)

NAME
     udbp -- USB Double Bulk Pipe driver

SYNOPSIS
     To compile this driver into the kernel, place the following line in your
     kernel configuration file:

	   device udbp

     Alternatively, to load the driver as a module at boot time, place the
     following line in loader.conf(5):

	   udbp_load="YES"

DESCRIPTION
     The  udbp	driver	provides support for host-to-host cables that contain at
     least two bulk pipes (one for each direction).  This typically includes ca-
     bles branded for use with Windows USB Easy Transfer, and many cables  based
     on  the Prolific PL2xx1 series of USB bridge chips.  A useful (but non-com-
     prehensive) list of compatible USB host cables is listed in the "SEE  ALSO"
     section below.

     It requires netgraph(4) to be available.  This can be done either by adding
     options  NETGRAPH to your kernel configuration file, or alternatively load-
     ing netgraph(4) as a module, either from /boot/loader.conf or from the com-
     mand line, before the udbp module.

EXAMPLES
	   options NETGRAPH
	   device udbp

     Add the udbp driver to the kernel.

	   kldload netgraph
	   kldload udbp

     Load the netgraph(4) module and then the udbp driver.

	   ngctl mkpeer udbp0: eiface data ether
	   ifconfig ngeth0 ether aa:dd:xx:xx:xx
	   ifconfig ngeth0 inet 169.254.x.x/16

     Create a new Ethernet network interface node and connect its ether hook  to
     the data hook of the udbp driver.

     This enables FreeBSD to communicate with a Linux peer (e.g. using the plusb
     driver).  The Linux node should be configured to prefer link-local IPv4 ad-
     dresses (e.g. using Network Manager in Debian and Red Hat derived distribu-
     tions).

     Whilst both FreeBSD and Linux are able to interoperate by loosely following
     CDC  EEM  1.0 in their behaviour, neither implementation has been expressly
     designed to follow its specification.

SEE ALSO
     netgraph(4), ng_eiface(4), ohci(4), uhci(4), usb(4), ngctl(8)

     Universal Serial Bus: Communications Class Subclass Specification for  Eth-
     ernet  Emulation Model Devices, USB Implementers Forum, Inc., Revision 1.0,
     http://www.usb.org/developers/docs/devclass_docs/CDC_EEM10.pdf, February 2,
     2005.

     Total Commander: Supported cables for USB cable connection,  Ghisler  Soft-
     ware GmbH., https://www.ghisler.com/cables/index.htm.

CAVEATS
     The  point-to-point  nature  and  additional latency of USB host-host links
     makes them unsuitable as a "drop-in" replacement for an Ethernet LAN; for a
     USB 3.0 SuperSpeed cable, latency is comparable to 100BaseTX Ethernet  (but
     often worse), with throughput comparable to 2.5GBASE-T.

     However,  their energy efficiency makes them attractive for embedded appli-
     cations.  A Plugable PL27A1 cable claims 24mA of USB3 bus	power,	as  com-
     pared to 150mA for a typical USB 3.0 to Gigabit Ethernet interface.

HISTORY
     The udbp driver first appeared in FreeBSD 5.0.

BUGS
     The  udbp	driver does not support the special packets described in section
     5.1 of the CDC EEM specification.

AUTHORS
     The udbp driver was written by Doug Ambrisko <ambrisko@whistle.com>, Julian
     Elischer <julian@FreeBSD.org> and Nick Hibma <n_hibma@FreeBSD.org>.

     This manual page was written by Nick Hibma  <n_hibma@FreeBSD.org>	and  up-
     dated by Bruce Simpson <bms@FreeBSD.org>.

FreeBSD 15.1			October 20, 2017			 UDBP(4)

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