AGR(4)

NAME
agr - link aggregation pseudo network interface driver

SYNOPSIS
pseudo-device agr

DESCRIPTION
The agr driver provides link aggregation functionality (a.k.a. L2 trunking or bonding).

It supports the IEEE 802.3ad Link Aggregation Control Protocol (LACP) and the Marker Protocol.

The agr driver supports the following link specific flags for ifconfig(8):

link0
    Use the round-robin distribution algorithm. Don't use it unless you're really sure, because it violates the frame ordering rule.

-link0
    Use the default distribution algorithm, which is based on the hash of DA/SA, TCI, and, if available, some upper layer protocol information like ip(4) DA/SA.

EXAMPLES
Create an agr interface, agr0, and attach re0 and re1 to it. (In other words, aggregate re0 and re1 so that they can be used as a single interface, agr0)

    	ifconfig agr0 create
    	ifconfig agr0 agrport re0
    	ifconfig agr0 agrport re1

Destroy an interface created in the above example.

    	ifconfig agr0 -agrport re0
    	ifconfig agr0 -agrport re1
    	ifconfig agr0 destroy

SEE ALSO
ifconfig(8)

STANDARDS
IEEE 802.3ad Aggregation of Multiple Link Segments

AUTHORS
The agr driver was written by YAMAMOTO Takashi.

BUGS
The current implementation of the agr driver always attempts automatic configuration via LACP. There is no way to configure statically or use non IEEE 802.3 devices.

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

The agr driver uses the MAC address of the first-added physical interface as the MAC address of the agr interface itself. Thus, removing the physical interface and using it for another purpose can result in non-unique MAC addresses.

The current implementation of the agr driver doesn't prevent unsafe operations like some ioctls against underlying physical interfaces. Such operations can result in unexpected behaviours, and are strongly discouraged.

There is no way to configure agr interfaces without attaching physical interfaces.

Physical interfaces being added to the agr interface shouldn't have any addresses except for link level address. Otherwise, the attempt will fail with EBUSY.