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CCNA 200-301 v1.1 reference — Network Access

EtherChannel and LACP

Layer 2 and Layer 3 bundles, LACP negotiation modes, member-link compatibility rules, and interpreting EtherChannel flags.

Objective 2.4v1.1 exam target

LACP mode combinations

PAgP equivalents: desirable/desirable or desirable/auto form; auto/auto does not.
Side ASide BResult
activeactiveBundle forms
activepassiveBundle forms (active initiates)
passivepassiveNo bundle — neither side initiates
ononForms with no negotiation — use with care
LACPPAgP/onNo bundle — protocols don't mix

PAgP equivalents: desirable/desirable or desirable/auto form; auto/auto does not.

Member compatibility requirements

  • Same speed and duplex on all members.
  • Same port mode (access/trunk) and the same VLAN/allowed-VLAN set.
  • Same STP cost contribution rules apply to the bundle as one logical link.
  • Consistent EtherChannel config on both ends — mismatched members can shut the bundle down.
Configure a Layer 2 LACP bundle

Bundle Gi1/0/1-2 into Po1 as a trunk — Privileged EXEC → Interface configuration

Cisco IOS / IOS XE

configure terminal
interface range gigabitethernet1/0/1 - 2
 channel-group 1 mode active
 exit
interface port-channel 1
 switchport mode trunk
 switchport trunk allowed vlan 10,20,30
 end
Verify
show etherchannel summary
show lacp neighbor
show interfaces port-channel 1
  • Members show (P) — bundled in the port-channel; (D)/(I) means down/stand-alone.
  • Po1 shows up/up with the trunk config inherited from the port-channel interface.
  • Layer 3 EtherChannel: no switchport + an IP on the port-channel interface instead.
  • Apply interface-level settings to the port-channel — members inherit them.

Changes device configuration.

$ show etherchannel summary (interpreted)
Group Port-channel Protocol PortsOne line per bundle.
1 Po1(SU) LACP Gi1/0/1(P) Gi1/0/2(P)SU = Layer 2, in use; (P) = bundled member.
Flags: D - down P - bundled in port-channelLearn the flag legend, not just the ports.
s - suspended S - Layer2 U - in useSuspended members signal a config mismatch.

Load balancing is per-flow, not per-packet: the hash (source/destination MAC, IP, or ports depending on platform) pins each conversation to one member. A single TCP session cannot exceed one member's bandwidth — the aggregate benefit is across many flows, not inside one.

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Targets CCNA 200-301 v1.1 objectives. Supplemental blocks are labeled beyond exam scope.

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EtherChannel and LACP | CCNA Study