LAGG(4) 						   BSD 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-toler-
     ance 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 specific 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 a static setup and does not negotiate aggregation with the peer or exchange frames to mon-
		  itor the link.

     lacp	  Supports the IEEE 802.3ad Link Aggregation Control Protocol (LACP) and the Marker Protocol.  LACP will negotiate a set of aggre-
		  gable 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.

EXAMPLES

     Create a 802.3ad link aggregation using LACP with two bge(4) Gigabit Ethernet 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.

BSD
								 October 18, 2010							       BSD