3.4.1. LACP Configuration
LACP (Link Aggregation Control Protocol - IEEE 802.3ad) is the open standard for EtherChannel negotiation.
| Mode | Description |
|---|---|
| Active | Actively initiates LACP negotiation |
| Passive | Responds to LACP but doesn't initiate |
Both sides must be active, or one active and one passive. Passive + passive never bundles, because neither side starts the negotiation. The channel-group number is locally significant, so the two ends need not use the same number.
PAgP is Cisco's proprietary alternative, with equivalent modes desirable (initiates) and auto (responds): desirable + desirable or desirable + auto bundles; auto + auto does not. Mode on forces a static bundle with no negotiation protocol, so it works only with on at the other end. LACP and PAgP do not interoperate: both ends must run the same protocol.
An EtherChannel carries up to 8 active links. LACP can hold up to 8 more members in hot-standby, ready to replace a failed active link.
Switch(config)# interface range GigabitEthernet0/1-2
Switch(config-if-range)# channel-group 1 mode active
Switch(config-if-range)# exit
Switch(config)# interface port-channel 1
Switch(config-if)# switchport mode trunk
Switch(config-if)# switchport trunk allowed vlan 10,20,30
