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.conf5:
if_lagg_load="YES"
DESCRIPTION
The
interface allows aggregation of multiple network interfaces as one virtual
interface for the purpose of providing fault-tolerance and high-speed links.
A
interface can be created using the
ifconfig lagg N 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),
feclacploadbalanceroundrobin
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 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.
fec
Supports Cisco EtherChannel.
This is a static setup and does not negotiate aggregation with the peer or
exchange frames to monitor the link.
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
interface itself.
Each
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.conf5.
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:
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:
An -nosplit
The
driver was written under the name
trunk
by
An Reyk Floeter Aq reyk@openbsd.org .
The LACP implementation was written by
An YAMAMOTO Takashi
for
Nx .
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.
WPA security does not currently work correctly with a wireless interface added
to the lagg port.
