EtherChannel Overview and Configuration guidelines.



EtherChannel Overview:
EtherChannel provides fault-tolerant, high-speed links between the switches, routers, and servers. An Ether-Channel consists of individual Fast-Ethernet or Gigabit-Ethernet links bundled into a single logical link. If a link within an EtherChannel fails, the traffic previously carried over that failed link changes to the remaining links within the Ether-Channel.



Interface Modes in EtherChannel:

Mode: On
Protocol: None
Detail: It forces the interface into an Ether-Channel without Port Aggregation Protocol or Link Aggregation Control Protocol. In which Channel only exists if connected to another interface group also in On mode.

Mode: Auto
Protocol: PAgP (Cisco Proprietary)
Detail: It will respond to PAgP packets but will not initiate PAgP negotiation

Mode: Desirable
Protocol: PAgP (Cisco Proprietary)
Detail: It will send PAgP packets to start negotiations.

Mode: Passive
Protocol: LACP (IEEE Proprietary) Passive Negotiations
Detail: It will respond to LACP packets but will not initiate LACP negotiation.

Mode: Active
Protocol: LACP (IEEE Proprietary) Active Negotiations
Detail: It will send LACP packets to start negotiations.

Guidelines for EtherChannel Configuration:

  Port Aggregation Protocol is Cisco proprietary and not compatible with Link Aggregation Control Protocol.
  LACP is defined in IEEE 802.3ad.
  A single EtherChannel can be made by combining two to eight parallel links.
  All ports must be followed below conditions:
  Speed and duplex must be Same
  It Cannot mix Fast Ethernet and Gigabit Ethernet
  It Cannot mix PAgP and LACP
  It Must all be VLAN trunk or non-trunk operational status
  All links must be either Layer 2 or Layer 3 in a single channel group member.
  For creation of a channel in PAgP, The sides must be set to one of the following:
  Auto-Desirable
  Desirable-Desirable

  For creation of a channel in LACP, The sides must be set to either:
  Active-Active
  Active-Passive
  For create a channel without using PAgP or LACP, The sides must be set to On-On.
  An interface that is already configured to be a Switched Port Analyzer (SPAN) destination port will not part of an EtherChannel group until SPAN is disabled.
  Don’t configure a secure port as part of an EtherChannel.
  The Interfaces with different native VLANs cannot form an EtherChannel.
  When using trunk links, Please ensure that all trunks ports are in the same trunking mode Inter-Switch Link (ISL) or dot1q.

Layer 2 EtherChannel Configuration:

L2Switch(config)#interface port-channel {number} 

L2Switch(config)#interface {Parameter}

     L2Switch(config)#interface range fastethernet 0/1 -6

L2Switch(config-if range)#channel-group 1 mode on

L2Switch(config-if-range)#channel-group 1 mode desirable

     L2Switch(config-if-range)#channel-group 1 mode active

If you are entering the channel-group command in the physical port interface mode without first setting a port channel command in global configuration mode, the port channel will automatically be created for us.

L3 EtherChannel Configuration:

L3Switch(config)#interface port-channel 1

L3Switch(config-if)#no switchport

L3Switch (config-if)#ip address 192.168.10.1 255.255.255.0

L3Switch (config-if)#exit

     L3Switch (config)#interface range fastethernet 0/20 – 23

L3Switch (config-if)#no switchport

L3Switch (config-if-range)#no ip address

L3Switch (config-if- range)#channel-group 1 mode on

L3Switch (config-if-range) #channel-group 1 mode desirable

L3Switch (config-if- range)#channel-group 1 mode active


Verifying EtherChannel:

L3Switch#show running-config

L3Switch#show running-config interface fastethernet 0/12

L3Switch#show interfaces fastethernet 0/12 etherchannel

L3Switch#show etherchannel

L3Switch#show etherchannel 1 port-channel

L3Switch#show etherchannel summary

L3Switch#show interface port-channel 1

L3Switch#show pagp neighbor

L3Switch#clear pagp 1 counters

L3Switch#clear lacp 1 counter


                    THANK YOU




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