HP ProCurve series 2500 Management And Configuration Manual page 132

Optimizing Port Usage Through Traffic Control and Port Trunking
Port Trunking
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. This 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.
Figure 6-10. Example of Criteria for Automatically Forming a Dynamic LACP Trunk
Syntax: interface <port-list> lacp active
This example uses ports 5 and 6 to enable a dynamic LACP trunk group.
HP2512(config)# interface 5-6 lacp active
6-22
Switch "A"
with ports set
to LACP
passive (the
default).
Switch "A"
with ports set
to LACP
active.
Dynamic LACP trunk cannot automatically form because both
ends of the links are LACP passive.
(In this case STP 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. (STP 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).