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.\" $OpenBSD: trunk.4,v 1.18 2006/06/09 13:53:34 jmc Exp $
.\"
.\" Copyright (c) 2005, 2006 Reyk Floeter <reyk@openbsd.org>
.\"
.\" Permission to use, copy, modify, and distribute this software for any
.\" purpose with or without fee is hereby granted, provided that the above
.\" copyright notice and this permission notice appear in all copies.
.\"
.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
.\"
.\" $FreeBSD$
.\"
.Dd March 6, 2007
.Dt TRUNK 4
.Os
.Sh NAME
.Nm trunk
.Nd link aggregation and link failover interface
.Sh SYNOPSIS
To compile this driver into the kernel,
place the following line in your
kernel configuration file:
.Bd -ragged -offset indent
.Cd "device trunk"
.Ed
.Pp
Alternatively, to load the driver as a
module at boot time, place the following line in
.Xr loader.conf 5 :
.Bd -literal -offset indent
if_trunk_load="YES"
.Ed
.Sh DESCRIPTION
The
.Nm
interface allows aggregation of multiple network interfaces as one virtual
.Nm
interface for the purpose of providing fault-tolerance and high-speed links.
.Pp
A
.Nm
interface can be created using the
.Ic ifconfig trunk Ns Ar N Ic create
command.
It can use different link aggregation protocols specified
using the
.Ic trunkproto Ar proto
option.
Child interfaces can be added using the
.Ic trunkport Ar child-iface
option and removed using the
.Ic -trunkport Ar child-iface
option.
.Pp
The driver currently supports the trunk protocols
.Ic failover
(the default),
.Ic fec ,
.Ic lacp ,
.Ic loadbalance ,
.Ic roundrobin ,
and
.Ic 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.
.Bl -tag -width loadbalance
.It Ic failover
Sends and receives traffic only through the master 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.
.It Ic fec
Supports Cisco EtherChannel.
This is a static setup and does not negotiate aggregation with the peer or
exchange frames to monitor the link.
.It Ic 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.
.It Ic 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.
.It Ic roundrobin
Distributes outgoing traffic using a round-robin scheduler
through all active ports and accepts incoming traffic from
any active port.
.It Ic none
This protocol is intended to do nothing: it disables any traffic without
disabling the
.Nm
interface itself.
.El
.Pp
Each
.Nm
interface is created at runtime using interface cloning.
This is
most easily done with the
.Xr ifconfig 8
.Cm create
command or using the
.Va cloned_interfaces
variable in
.Xr rc.conf 5 .
.Sh EXAMPLES
Create a 802.3ad trunk using LACP with two
.Xr bge 4
Gigabit Ethernet interfaces:
.Bd -literal -offset indent
# ifconfig bge0 up
# ifconfig bge1 up
# ifconfig trunk0 trunkproto lacp trunkport bge0 trunkport bge1 \e
192.168.1.1 netmask 255.255.255.0
.Ed
.Pp
The following example uses an active failover trunk 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:
.Bd -literal -offset indent
# ifconfig em0 up
# ifconfig ath0 nwid my_net up
# ifconfig trunk0 trunkproto failover trunkport em0 trunkport ath0 \e
192.168.1.1 netmask 255.255.255.0
.Ed
.Sh SEE ALSO
.Xr ng_fec 4 ,
.Xr ng_one2many 4 ,
.Xr ifconfig 8
.Sh HISTORY
The
.Nm
device first appeared in
.Fx 7.0 .
.Sh AUTHORS
.An -nosplit
The
.Nm
driver was written by
.An Reyk Floeter Aq reyk@openbsd.org .
The LACP implementation was written by
.An YAMAMOTO Takashi
for
.Nx .
.Sh 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.
.Pp
WPA security does not currently work correctly with a wireless interface added
to the trunk.
|
