UDBP(4)                FreeBSD 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
     cables 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-comprehensive) 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 loading netgraph(4) as a module, either from
     /boot/loader.conf or from the command 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 addresses (e.g. using Network Manager in Debian and Red Hat derived
     distributions).

     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
     Ethernet 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
     Software 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
     applications.  A Plugable PL27A1 cable claims 24mA of USB3 bus power, as
     compared 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
     updated by Bruce Simpson <bms@FreeBSD.org>.

FreeBSD 13.1-RELEASE-p6        October 20, 2017        FreeBSD 13.1-RELEASE-p6