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LAGG(4)		       FreeBSD Kernel Interfaces Manual		       LAGG(4)

NAME
     lagg -- link aggregation and link failover	interface

SYNOPSIS
     To	compile	this driver into the kernel, place the following line in your
     kernel configuration file:

	   device lagg

     Alternatively, to load the	driver as a module at boot time, place the
     following line in loader.conf(5):

	   if_lagg_load="YES"

DESCRIPTION
     The lagg interface	allows aggregation of multiple network interfaces as
     one virtual lagg interface	for the	purpose	of providing fault-tolerance
     and high-speed links.

     A lagg interface can be created using the ifconfig	laggN create command.
     It	can use	different link aggregation protocols specified using the
     laggproto proto option.  Child interfaces can be added using the laggport
     child-iface option	and removed using the -laggport	child-iface option.

     The driver	currently supports the aggregation protocols failover (the
     default), fec, lacp, loadbalance, roundrobin, and none.  The protocols
     determine which ports are used for	outgoing traffic and whether a spe-
     cific port	accepts	incoming traffic.  The interface link state is used to
     validate if the port is active or not.

     failover	  Sends	traffic	only through the active	port.  If the master
		  port becomes unavailable, the	next active port is used.  The
		  first	interface added	is the master port; any	interfaces
		  added	after that are used as failover	devices.

		  By default, received traffic is only accepted	when they are
		  received through the active port.  This constraint can be
		  relaxed by setting the net.link.lagg.failover_rx_all
		  sysctl(8) variable to	a nonzero value, which is useful for
		  certain bridged network setups.

     fec	  Supports Cisco EtherChannel.	This is	an alias for
		  loadbalance mode.

     lacp	  Supports the IEEE 802.3ad Link Aggregation Control Protocol
		  (LACP) and the Marker	Protocol.  LACP	will negotiate a set
		  of aggregable	links with the peer in to one or more Link
		  Aggregated Groups.  Each LAG is composed of ports of the
		  same speed, set to full-duplex operation.  The traffic will
		  be balanced across the ports in the LAG with the greatest
		  total	speed, in most cases there will	only be	one LAG	which
		  contains all ports.  In the event of changes in physical
		  connectivity,	Link Aggregation will quickly converge to a
		  new configuration.

     loadbalance  Balances outgoing traffic across the active ports based on
		  hashed protocol header information and accepts incoming
		  traffic from any active port.	 This is a static setup	and
		  does not negotiate aggregation with the peer or exchange
		  frames to monitor the	link.  The hash	includes the Ethernet
		  source and destination address, and, if available, the VLAN
		  tag, and the IP source and destination address.

     roundrobin	  Distributes outgoing traffic using a round-robin scheduler
		  through all active ports and accepts incoming	traffic	from
		  any active port.

     none	  This protocol	is intended to do nothing: it disables any
		  traffic without disabling the	lagg interface itself.

     Each lagg interface 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).

     The MTU of	the first interface to be added	is used	as the lagg MTU.  All
     additional	interfaces are required	to have	exactly	the same value.

     The loadbalance and lacp modes will use the RSS hash from the network
     card if available to avoid	computing one, this may	give poor traffic dis-
     tribution if the hash is invalid or uses less of the protocol header
     information.  Local hash computation can be forced	per interface by set-
     ting the net.link.lagg.X.use_flowid sysctl(8) variable to zero where X is
     the interface number.  The	default	for new	interfaces is set via the
     net.link.lagg.default_use_flowid sysctl(8).

EXAMPLES
     Create a 802.3ad link aggregation using LACP with two bge(4) Gigabit Eth-
     ernet interfaces:

	   # ifconfig bge0 up
	   # ifconfig bge1 up
	   # ifconfig lagg0 laggproto lacp laggport bge0 laggport bge1 \
		   192.168.1.1 netmask 255.255.255.0

     The following example uses	an active failover interface to	set up roaming
     between wired and wireless	networks using two network devices.  Whenever
     the wired master interface	is unplugged, the wireless failover device
     will be used:

	   # ifconfig em0 up
	   # ifconfig ath0 ether 00:11:22:33:44:55
	   # ifconfig create wlan0 wlandev ath0	ssid my_net up
	   # ifconfig lagg0 laggproto failover laggport	em0 laggport wlan0 \
		   192.168.1.1 netmask 255.255.255.0

     (Note the mac address of the wireless device is forced to match the wired
     device as a workaround.)

SEE ALSO
     ng_fec(4),	ng_one2many(4),	sysctl(8), ifconfig(8)

HISTORY
     The lagg device first appeared in FreeBSD 6.3.

AUTHORS
     The lagg driver was written under the name	trunk by Reyk Floeter
     <reyk@openbsd.org>.  The LACP implementation was written by YAMAMOTO
     Takashi for NetBSD.

BUGS
     There is no way to	configure LACP administrative variables, including
     system and	port priorities.  The current implementation always performs
     active-mode LACP and uses 0x8000 as system	and port priorities.

FreeBSD	9.2		       February	23, 2012		   FreeBSD 9.2

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

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<http://www.freebsd.org/cgi/man.cgi?query=lagg&manpath=FreeBSD+9.3-RELEASE>

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