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 links are held in standby status. If a trunked link that is "Up" fails, it is replaced by a standby link, which maintains your intended bandwidth for the trunk. In this example, ports A1 through A9 have been configured for the same LACP trunk. Notice that one of the links shows Standby port status, while the remaining eight links show Up port status.

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