1 .\" $OpenBSD: trunk.4,v 1.18 2006/06/09 13:53:34 jmc Exp $
3 .\" Copyright (c) 2005, 2006 Reyk Floeter <reyk@openbsd.org>
5 .\" Permission to use, copy, modify, and distribute this software for any
6 .\" purpose with or without fee is hereby granted, provided that the above
7 .\" copyright notice and this permission notice appear in all copies.
9 .\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 .\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 .\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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14 .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15 .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
24 .Nd link aggregation and link failover interface
26 To compile this driver into the kernel,
27 place the following line in your
28 kernel configuration file:
29 .Bd -ragged -offset indent
33 Alternatively, to load the driver as a
34 module at boot time, place the following line in
36 .Bd -literal -offset indent
42 interface allows aggregation of multiple network interfaces as one virtual
44 interface for the purpose of providing fault-tolerance and high-speed links.
48 interface can be created using the
49 .Ic ifconfig lagg Ns Ar N Ic create
51 It can use different link aggregation protocols specified
53 .Ic laggproto Ar proto
55 Child interfaces can be added using the
56 .Ic laggport Ar child-iface
57 option and removed using the
58 .Ic -laggport Ar child-iface
61 The driver currently supports the aggregation protocols
70 The protocols determine which ports are used for outgoing traffic
71 and whether a specific port accepts incoming traffic.
72 The interface link state is used to validate if the port is active or
74 .Bl -tag -width loadbalance
76 Sends traffic only through the active port.
77 If the master port becomes unavailable,
78 the next active port is used.
79 The first interface added is the master port;
80 any interfaces added after that are used as failover devices.
82 By default, received traffic is only accepted when they are received
83 through the active port.
84 This constraint can be relaxed by setting the
85 .Va net.link.lagg.failover_rx_all
87 variable to a nonzero value,
88 which is useful for certain bridged network setups.
90 Supports Cisco EtherChannel.
91 This is a static setup and does not negotiate aggregation with the peer or
92 exchange frames to monitor the link.
94 Supports the IEEE 802.3ad Link Aggregation Control Protocol (LACP) and the
96 LACP will negotiate a set of aggregable links with the peer in to one or more
97 Link Aggregated Groups.
98 Each LAG is composed of ports of the same speed, set to full-duplex operation.
99 The traffic will be balanced across the ports in the LAG with the greatest
100 total speed, in most cases there will only be one LAG which contains all ports.
101 In the event of changes in physical connectivity, Link Aggregation will quickly
102 converge to a new configuration.
104 Balances outgoing traffic across the active ports based on hashed
105 protocol header information and accepts incoming traffic from
107 This is a static setup and does not negotiate aggregation with the peer or
108 exchange frames to monitor the link.
109 The hash includes the Ethernet source and destination address, and, if
110 available, the VLAN tag, and the IP source and destination address.
112 Distributes outgoing traffic using a round-robin scheduler
113 through all active ports and accepts incoming traffic from
116 This protocol is intended to do nothing: it disables any traffic without
124 interface is created at runtime using interface cloning.
126 most easily done with the
130 .Va cloned_interfaces
134 The MTU of the first interface to be added is used as the lagg MTU.
135 All additional interfaces are required to have exactly the same value.
137 Create a 802.3ad link aggregation using LACP with two
139 Gigabit Ethernet interfaces:
140 .Bd -literal -offset indent
143 # ifconfig lagg0 laggproto lacp laggport bge0 laggport bge1 \e
144 192.168.1.1 netmask 255.255.255.0
147 The following example uses an active failover interface to set up roaming
148 between wired and wireless networks using two network devices.
149 Whenever the wired master interface is unplugged, the wireless failover
151 .Bd -literal -offset indent
153 # ifconfig ath0 ether 00:11:22:33:44:55
154 # ifconfig create wlan0 wlandev ath0 ssid my_net up
155 # ifconfig lagg0 laggproto failover laggport em0 laggport wlan0 \e
156 192.168.1.1 netmask 255.255.255.0
159 (Note the mac address of the wireless device is forced to match the wired
160 device as a workaround.)
169 device first appeared in
175 driver was written under the name
178 .An Reyk Floeter Aq reyk@openbsd.org .
179 The LACP implementation was written by
184 There is no way to configure LACP administrative variables, including system
186 The current implementation always performs active-mode LACP and uses 0x8000 as
187 system and port priorities.