Full form: Link Aggregation Control Protocol
Also known as: Link Aggregation Control Protocol, IEEE 802.3ad, 802.3ad
Quick Definition
The IEEE 802.3ad open-standard protocol used to negotiate EtherChannel formation.
LACP (IEEE 802.3ad) is an open-standard protocol for negotiating EtherChannel (link aggregation). LACP modes are: Active (initiates negotiation) and Passive (waits for the other side). A channel forms if at least one side is Active. LACP is preferred over PAgP for multi-vendor environments and is the modern standard. LACP supports up to 16 member ports per bundle (8 active, 8 standby).
interface range GigabitEthernet0/1-2 channel-group 1 mode active ! LACP active — initiates channel-group 1 mode passive ! LACP passive — waits
Passive-Passive does NOT form a channel (neither side initiates). At least one side must be Active. Active-Active, Active-Passive all work.
LACP (IEEE 802.3ad) is an open-standard protocol for negotiating EtherChannel (link aggregation). LACP modes are: Active (initiates negotiation) and Passive (waits for the other side). A channel forms if at least one side is Active. LACP is preferred over PAgP for multi-vendor environments and is the modern standard. LACP supports up to 16 member ports per bundle (8 active, 8 standby).
Passive-Passive does NOT form a channel (neither side initiates). At least one side must be Active. Active-Active, Active-Passive all work.
LACP falls under the Switching domain of the 200-301 exam. Understanding it in context with related terms like etherchannel and pagp is essential for answering scenario-based questions correctly.