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EPAIR(4)	       FreeBSD Kernel Interfaces Manual		      EPAIR(4)

     epair -- A	pair of	virtual	back-to-back connected Ethernet	interfaces.

     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):


     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
     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 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.

     ioctl(2), altq(4),	bpf(4),	if_bridge(4), vlan(4), loader.conf(5,)
     rc.conf(5), ifconfig(8)

     The epair interface first appeared	in FreeBSD 8.0.

     The epair interface was written by	Bjoern A. Zeeb,	CK Software GmbH,
     under sponsorship from the	FreeBSD	Foundation.

FreeBSD	8.0			 July 26, 2009			   FreeBSD 8.0


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