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EPAIR(4)		 BSD 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 con-
     nected 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 ad-
     dress.  Each epair	will be	assigned a locally administered	address	by de-
     fault, that is only guaranteed to be unique within	one network stack.  To
     change the	default	addresses one may use the SIOCSIFADDR ioctl(2) or if-
     config(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 inter-
     face 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, un-
     der sponsorship from the FreeBSD Foundation.

BSD				 July 26, 2009				   BSD

NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | HISTORY | AUTHORS

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