Also known as: LAG, link aggregation, port channel, port-channel, bundle
Quick Definition
A link aggregation technology that bundles multiple physical Ethernet links into one logical link.
EtherChannel combines 2–8 parallel Ethernet links into a single logical channel, multiplying bandwidth and providing redundancy. If one physical link fails, traffic redistributes across the remaining links without STP reconvergence. STP sees the entire bundle as a single link. EtherChannel can be negotiated using LACP (IEEE 802.3ad) or PAgP (Cisco proprietary), or forced manually using static mode.
interface range GigabitEthernet0/1-2 channel-group 1 mode active ! LACP active channel-group 1 mode desirable ! PAgP interface Port-channel 1 switchport mode trunk
All ports in an EtherChannel must have matching configuration: same speed, duplex, VLAN assignment, trunk settings, and STP settings. Mismatched ports cause the channel to fail to form.
EtherChannel combines 2–8 parallel Ethernet links into a single logical channel, multiplying bandwidth and providing redundancy. If one physical link fails, traffic redistributes across the remaining links without STP reconvergence. STP sees the entire bundle as a single link. EtherChannel can be negotiated using LACP (IEEE 802.3ad) or PAgP (Cisco proprietary), or forced manually using static mode.
All ports in an EtherChannel must have matching configuration: same speed, duplex, VLAN assignment, trunk settings, and STP settings. Mismatched ports cause the channel to fail to form.
EtherChannel falls under the Switching domain of the 200-301 exam. Understanding it in context with related terms like lacp and pagp is essential for answering scenario-based questions correctly.