EPAIR(4)               FreeBSD Kernel Interfaces Manual               EPAIR(4)

NAME
     epair - A pair of virtual back-to-back connected Ethernet interfaces

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

           device epair

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

           if_epair_load="YES"

DESCRIPTION
     The epair is a pair of Ethernet-like software interfaces, which are
     connected back-to-back with a virtual cross-over cable.

     Each epair interface pair is created at runtime using interface cloning.
     This is most easily done with the ifconfig(8) create command or using the
     cloned_interfaces variable in rc.conf(5).  While for cloning you only
     give either epair or epair<n> the epair pair will be named like
     epair<n>[ab].  This means the names of the first epair interfaces will be
     epair0a and epair0b.

     Like any other Ethernet interface, an epair needs to have a network
     address.  Each epair will be assigned a locally administered address by
     default, that is only guaranteed to be unique within one network stack.
     To change the default addresses one may use the SIOCSIFADDR ioctl(2) or
     ifconfig(8) utility.

     The basic intent is to provide connectivity between two virtual network
     stack instances.  When connected to an if_bridge(4), one end of the
     interface pair can also be part of another (virtual) LAN.  As with any
     other Ethernet interface, epair can have a vlan(4) configured on top of
     it.

SEE ALSO
     ioctl(2), altq(4), bpf(4), if_bridge(4), vlan(4), loader.conf(5),
     rc.conf(5), ifconfig(8)

HISTORY
     The epair interface first appeared in FreeBSD 8.0.

AUTHORS
     The epair interface was written by Bjoern A. Zeeb, CK Software GmbH,
     under sponsorship from the FreeBSD Foundation.

FreeBSD 13.1-RELEASE-p6         March 18, 2015         FreeBSD 13.1-RELEASE-p6