freebsd-skq/share/man/man4/epair.4
bz e1dc108b61 Merge from p4: CH154790,154793,154874
Import if_epair(4), a virtual cross-over Ethernet-like interface pair.

Note these files are 1:1 from p4 and not yet connected to the build
not knowing about the new netisr interface.

Sponsored by:	The FreeBSD Foundation
2009-06-24 22:21:30 +00:00

121 lines
3.3 KiB
Groff

.\"-
.\" Copyright (c) 2008 The FreeBSD Foundation
.\" All rights reserved.
.\"
.\" This software was developed by CK Software GmbH under sponsorship
.\" from the FreeBSD Foundation.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\" notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in the
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" $FreeBSD$
.\"
.Dd December 15, 2008
.Dt EPAIR 4
.Os
.Sh NAME
.Nm epair
.Nd Virtual cross-over Ethernet-like interface pair.
.Sh SYNOPSIS
To compile this driver into the kernel,
place the following line in your
kernel configuration file:
.Bd -ragged -offset indent
.Cd "device epair"
.Ed
.Pp
Alternatively, to load the driver as a
module at boot time, place the following line in
.Xr loader.conf 5 :
.Bd -literal -offset indent
if_epair_load="YES"
.Ed
.Sh DESCRIPTION
The
.Nm
is a pair of Ethernet-like software interfaces,
which are directly connected by a virtual cross-over cable.
.Pp
Each
.Nm
interface pair is created at runtime using interface cloning.
This is most easily done with the
.Xr ifconfig 8
.Cm create
command or using the
.Va cloned_interfaces
variable in
.Xr rc.conf 5 .
While for cloning you only give either
.Pa epair
or
.Pa epair<n>
the
.Nm
pair will be named like
.Pa epair<n>[ab] .
This means the names of the first
.Nm
interfaces will be
.Pa epair0a
and
.Pa epair0b .
.Pp
Like any other Ethernet interface, an
.Nm
needs to have a network address.
Each
.Nm
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.
.Pp
The basic intend is to provide connectivity between two virtual
network stack instances.
When connected to a
.Xr 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
.Xr vlan 4
support on top of it.
.Pp
.Sh SEE ALSO
.Xr ioctl 2 ,
.Xr altq 4 ,
.Xr bpf 4 ,
.Xr if_bridge 4 ,
.Xr vlan 4 ,
.Xr loader.conf 5,
.Xr rc.conf 5 ,
.Xr ifconfig 8
.Sh HISTORY
The
.Nm
interface first appeared in
.Fx 8.0 .
.Sh AUTHORS
The
.Nm
interface was written by
.An Bjoern A. Zeeb, CK Software GmbH,
under sponsorship from the FreeBSD Foundation.