| AGR(4) | Device Drivers Manual | AGR(4) | 
agr —
pseudo-device agr
lagg(4) should be used instead.
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-link0link1agr 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. The physical interfaces
  which are attached to the agr interface must not have
  any IP addresses, neither IPv4 nor IPv6.
ifconfig re0 inet xxx.xxx.xxx.xxx delete ifconfig re0 inet6 fe80::xxxx:xxxx:xxxx:xxxx delete ifconfig re1 inet xxx.xxx.xxx.xxx delete ifconfig re1 inet6 fe80::xxxx:xxxx:xxxx:xxxx delete 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
agr driver first appeared in NetBSD
  4.0 and was obsoleted in NetBSD 10.0.
The agr driver will be removed from
    NetBSD 11.0.
agr driver was written by YAMAMOTO
  Takashi.
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 behaviors, 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. Note
    that it includes an automatically assigned IPv6 link-local address.
| February 23, 2010 | NetBSD 10.0 |