EtherChannel Flashcards
What is EtherChannel?
A technology that bundles multiple physical links into a single logical link to increase bandwidth and provide redundancy.
What protocols can negotiate EtherChannel?
LACP (Link Aggregation Control Protocol) and PAgP (Port Aggregation Protocol).
What does the “channel-group” command do?
Assigns a physical interface to an EtherChannel group and sets the negotiation mode.
What is the purpose of the “port-channel” interface?
It represents the logical bundle of physical ports for configuration like VLANs or trunking.
Command to assign ports Gi0/1 and Gi0/2 to EtherChannel group 1 with LACP active?
interface range gi0/1 - 2\nchannel-group 1 mode active
What does “mode on” mean in EtherChannel?
Static EtherChannel with no negotiation protocol (manual bundling).
What must match on all ports in an EtherChannel group?
Speed
Command to set an EtherChannel as a trunk?
interface port-channel 1\nswitchport mode trunk
What does “show etherchannel summary” display?
EtherChannel group status
What happens if speed settings differ in an EtherChannel group?
The bundle won�t form
What is LACP “active” mode?
The port actively initiates EtherChannel negotiation with its peer.
What is PAgP “desirable” mode?
The port actively seeks to form an EtherChannel with a compatible peer.
Command to check EtherChannel load-balancing method?
show etherchannel load-balance
Default EtherChannel load-balancing method on Cisco switches?
Source MAC address (src-mac).
Command to set load balancing to source-destination IP?
port-channel load-balance src-dst-ip
What does “P” mean in “show etherchannel summary” output?
The port is bundled and active in the EtherChannel.
What does “D” mean in “show etherchannel summary” output?
The port is down and not part of the EtherChannel.
Command to verify STP status on an EtherChannel?
show spanning-tree interface port-channel 1
Why use EtherChannel over a single link?
Increases bandwidth and provides link redundancy if one fails.
What is the max number of ports in an EtherChannel (typical Cisco limit)?
8 (though platform-dependent; some support 16).
Command to configure EtherChannel with PAgP auto mode?
channel-group 1 mode auto
What happens if VLAN settings mismatch in an EtherChannel?
Ports may be suspended
Command to view detailed EtherChannel info?
show etherchannel 1 detail
Can PortFast be enabled on EtherChannel ports?
No
