this means that it no longer grabs the lagg rwlock. Use two port table arrays
which list the active ports for Tx and switch between them with an atomic op.
Now the lagg rwlock is only exclusively locked for management (ioctls) and
queuing of lacp control frames isnt needed.
of each port and any further packets are blocked, when the all the marker frames
have been returned to us from the remote network device then we can be sure
that all interface queues are empty.
This is needed when a port is added or removed from the aggregation since it
will affect the hash based distribution, if the queues are not empty then a
packet from an existing connection may be placed on a different interface and
arrive out of order. This was previously achieved by suppressing transmission for
1 second, now that there is an active feedback this timeout as been increased
to 3 seconds and used as a fallback.
The name trunk is misused as the networking term trunk means carrying multiple
VLANs over a single connection. The IEEE standard for link aggregation (802.3
section 3) does not talk about 'trunk' at all while it is used throughout IEEE
802.1Q in describing vlans.
The lagg(4) driver provides link aggregation, failover and fault tolerance.
Discussed on: current@
tolerance. This driver allows aggregation of multiple network interfaces as
one virtual interface using a number of different protocols/algorithms.
failover - Sends traffic through the secondary port if the master becomes
inactive.
fec - Supports Cisco Fast EtherChannel.
lacp - Supports the IEEE 802.3ad Link Aggregation Control Protocol
(LACP) and the Marker Protocol.
loadbalance - Static loadbalancing using an outgoing hash.
roundrobin - Distributes outgoing traffic using a round-robin scheduler
through all active ports.
This code was obtained from OpenBSD and this also includes 802.3ad LACP support
from agr(4) in NetBSD.
