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):
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 intend is to provide connectivity between two virtual network stack
instances. When connected to a
if_bridge(4) one end of the
interface pair can also be part of another (virtual) LAN. As with any other
Ethernet interface one can configure
vlan(4) support 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.