



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 :





On Mode:

None Protocol:

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. : 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.





Auto Mode:

PAgP (Cisco Proprietary) Protocol:

Detail: It will respond to PAgP packets but will not initiate PAgP negotiation : It will respond to PAgP packets but will not initiate PAgP negotiation





Desirable Mode:

PAgP (Cisco Proprietary) Protocol:

Detail: It will send PAgP packets to start negotiations. : It will send PAgP packets to start negotiations.





Passive Mode:

LACP (IEEE Proprietary) Passive Negotiations Protocol:

Detail: It will respond to LACP packets but will not initiate LACP negotiation . : Ittobutnot





Active Mode:

LACP (IEEE Proprietary) Active Negotiations Protocol:

Detail: It will send LACP packets to start negotiations. : It will send LACP packets to start negotiations.





Guidelines for EtherChannel Configuration: Configuration:





■ Port Aggregation Protocol is Cisco proprietary and not compatible with the Link Aggregation Control Protocol. Port Aggregation Protocol is Cisco proprietary and not compatible with the Link Aggregation Control Protocol.

■ LACP is defined in IEEE 802.3ad. LACP is defined in802.3ad.

■ links. A single EtherChannel can be made by combining two to eight parallellinks.

■ All ports must be followed below conditions: All ports must befollowed below conditions:

■ Speed and duplex must be Same Speed andduplex must be Same

■ It Cannot mix Fast Ethernet and Gigabit Ethernet It Cannot mix Fast Ethernet and GigabitEthernet

■ It Cannot mix PAgP and LACP It Cannot mix PAgP andLACP

■ It Must all be VLAN trunk or non-trunk operational status It Must all be VLAN trunk or non-trunk operationalstatus

■ All links must be either Layer 2 or Layer 3 in a single channel group member. AlllinksmustbeeitherLayerorLayerinsinglechannelgroup member.

■ For the creation of a channel in PAgP, The sides must be set to one of the following: ForcreationchannelinPAgP, Thesidesmustbesettooneofthefollowing:

■ Auto-Desirable Auto-Desirable

■ Desirable-Desirable Desirable-Desirable





■ For the creation of a channel in LACP, The sides must be set to either: For the creation of a channel in LACP, The sides must be set toeither:

■ Active-Active Active-Active

■ Active-Passive Active-Passive

■ For creating a channel without using PAgP or LACP, The sides must be set to On-On. ForcreatingchannelwithoutusingPAgPorLACP, ThesidesmustbesettoOn-On.

■ disabled. An interface that is already configured to be a Switched Port Analyzer (SPAN) destination port will not part of an EtherChannel group until SPAN isdisabled.

■ Don’t configure a secure port as part of an EtherChannel. Don’t configure a secure port as part of anEtherChannel.

■ The Interfaces with different native VLANs cannot form an EtherChannel. The Interfaces with different native VLANs cannot form anEtherChannel.

■ dot1q. When using trunk links, Please ensure that all trunks ports are in the same trunking mode Inter-Switch Link (ISL) ordot1q.





Layer 2 EtherChannel Configuration: Configuration:





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





interface {Parameter} L2Switch(config)#





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





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





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





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 :





interface port-channel 1 L3Switch(config)#





no switchport L3Switch(config-if)#





ip address 192.168.10.1 255.255.255.0 L3Switch (config-if)#





exit L3Switch (config-if)#





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





no switchport L3Switch (config-if)#





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 L3Switch (config-if- range)#









Verifying EtherChannel :





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 L3Switch#



