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EPAIR(4)		 BSD 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 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.

     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, un-
     der sponsorship from the FreeBSD Foundation.

BSD				 July 26, 2009				   BSD


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