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 epairAlternatively, to load the driver as a module at boot time, place the following line in loader.conf(5):
if_epair_load="YES"
DESCRIPTION
Theepair 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.