HP ProCurve 6400cl Series Management And Configuration Manual page 260

Port Trunking
CLI: Viewing and Configuring Port Trunk Groups
12-16
Enabling a Dynamic LACP Trunk Group. In the default port configura­
tion, all ports on the switch are set to LACP Passive. However, to enable the
switch to automatically form a trunk group that is dynamic on both ends of
the link, the ports on one end of a set of links must be LACP Active. The ports
on the other end can be either LACP Active or LACP Passive. The active
command enables the switch to automatically establish a (dynamic) LACP
trunk group when the device on the other end of the link is configured for
LACP Passive.
Switch "A"
with ports set
to LACP
passive (the
default).
Switch "A"
with ports set
to LACP
active.
Figure 12-10. Example of Criteria for Automatically Forming a Dynamic LACP Trunk
Syntax: interface < port-list > lacp active
Configures < port-list > as LACP active. If the ports at the other
end of the links on < port-list > are configured as LACP passive,
then this command enables a dynamic LACP trunk group on
< port-list >.
This example uses ports C4 and C5 to enable a dynamic LACP trunk group.
HPswitch(config)# interface c4-c5 lacp active
Dynamic LACP trunk cannot automatically form because both
ends of the links are LACP passive.
(In this case spanning-tree blocking is needed to prevent a loop.
Dynamic LACP trunk automatically forms because both
ends of the links are LACP and at least one end is LACP
active. (Spanning tree is not needed, and the clear
advantages are increased bandwidth and fault-tolerance.)
Switch "B"
with ports set
to LACP
passive (the
default).
Switch "B"
with ports set
to LACP
passive (the
default).