EtherChannel Flashcards
What is the benefit of having multiple links between devices?
Redundancy and increased bandwidth.
What is the function of EtherChannel?
It groups several physical ports into one logical channel. (One benefit of this grouping is that STP won’t block any of these ports in the interest of preventing loops - this way you can have multiple links in use between two layer 2 or layer 3 devices)
What are the two protocols that can be used to configure EtherChannel?
PAgP - Cisco proprietary
LACP - 802.3ad IEEE standard
In PAgP, what are the two port channel modes and what do they do?
Desirable - configures port to ask other side if it can or will participate in EtherChannel
Auto - configures port to wait for other side to determine port channel status
In LACP, what are the two modes and what do they do?
Active - actively asks whether other side can or will participate
Passive - waits for other side to initiate negotiation
All interfaces within an EtherChannel must have the same configuration for what four things?
- Speed and duplex
- Mode (access port or trunk port)
- Native and allowed VLANs on
trunk ports - Access VLAN on access ports
What are the commands you would use to configure EtherChannel?
Create bundle:
interface range (FastEthernet 0/1 - 2)
channel-group 1 mode (on/active/passive/desirable/auto)
exit
Configure as trunk or access port:
interface port-channel 1
switchport mode (trunk/access)
if trunk:
switchport trunk allowed VLAN (desired allowed VLAN #’s, comma delineated)
What are the commands you can use to verify EtherChannel configuration?
show interface port-channel 1 (or whatever port channel you’ve created)
show EtherChannel summary: summary per channel group
show EtherChannel port-channel:
shows port channel info