bionic (4) epair.4freebsd.gz

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.