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-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
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