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".) 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”.
A Dynamic LACP trunk with one standby link
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
A4 Active Dyn1 Up Yes Success 100 100
A5 Active Dyn1 Up Yes Success 100 100
A6 Active Dyn1 Up Yes Success 100 100
A7 Active Dyn1 Up Yes Success 100 100
A8 Active Dyn1 Up Yes Success 100 100
A9 Active Dyn1 Standby Yes Success 100 100