Management and Configuration Guide K/KA/KB.15.15

of eight actively trunking ports.) The trunks do not have to be the same size; for example, 100
two-port trunks and 11 eight-port trunks are supported.
NOTE: LACP requires full-duplex (FDx) links of the same media type (10/100Base-T, 100FX,
and so on) and the same speed, and enforces speed and duplex conformance across a trunk
group. For most installations, HP Switch recommends that you leave the port Mode settings at Auto
(the default.) LACP also operates with Auto-10, Auto-100, and Auto-1000 (if negotiation
selects FDx), and 10FDx, 100FDx, and 1000FDx settings. (The 10-gigabit ports available
for some switch models allow only the Auto setting.)
Fault tolerance
If a link in a port trunk fails, the switch redistributes traffic originally destined for that link to the
remaining links in the trunk. The trunk remains operable as long as there is at least one link in
operation. If a link is restored, that link is automatically included in the traffic distribution again.
The LACP option also offers a standby link capability, which enables you to keep links in reserve
for service if one or more of the original active links fails. (See “Trunk group operation using LACP”
(page 152).)
Trunk configuration methods
Dynamic LACP trunk
The switch automatically negotiates trunked links between LACP-configured ports on separate
devices, and offers one dynamic trunk option: LACP. To configure the switch to initiate a dynamic
LACP trunk with another device, use the interface command in the CLI to set the default LACP
option to active on the ports you want to use for the trunk. For example, the following command
sets ports C1 to C4 to LACP active:
HP Switch(config) int c1-c4 lacp active
The preceding example works if the ports are not already operating in a trunk. To change the
LACP option on ports already operating as a trunk, you must first remove them from the trunk. For
example, if ports C1 to C4 are LACP-active and operating in a trunk with another device, you
would do the following to configure them to LACP-passive:
(HP_Switch_name#) no int c1-c4 lacp
Removes the ports from the trunk:
(HP_Switch_name#) int c1-c4 lacp passive
Dynamic LACP Standby Links
Dynamic LACP trunking enables you to configure standby links for a trunk by including more than
eight ports in a dynamic LACP trunk configuration. When eight ports (trunk links) are up, the
remaining link(s) will be held in standby status. If a trunked link that is “Up” fails, it will be replaced
by a standby link, which maintains your intended bandwidth for the trunk. (Refer to also the
“Standby” entry under “Port Status” in "Table 4-5. LACP Port Status Data" on page 4-22.) In the
next example, ports A1 through A9 have been configured for the same LACP trunk. Notice that
one of the links shows Standby status, while the remaining eight links are “Up”.
HP Switch> show lacp
LACP
LACP Trunk Port LACP Admin Oper
Port Enabled Group Status Partner Status Key Key
---- ------- ----- ------ ------- ------ ---- -----
Al Active Dyn1 Up Yes Success 100 100
A2 Active Dyn1 Up Yes Success 100 100
A3 Active Dyn1 Up Yes Success 100 100
Trunk configuration methods 145