The diagram below shows the layout of the switches.
Before starting I make sure all interfaces that I will be configuring for EtherChannel have no configuration and are in the same VLAN.
I use the following commands to configure EtherChannel on the switches.
switch1#conf t
Enter configuration commands, one per line. End with CNTL/Z.
switch1(config)#interface fastEthernet 0/1
switch1(config-if)#channel-group 5 mode desirable
Creating a port-channel interface Port-channel 5
switch1(config-if)#exit
switch1(config)#interface fastEthernet 0/24
switch1(config-if)#channel-group 5 mode desirable
Creating a port-channel interface Port-channel 5
switch1(config-if)#end
switch2#conf t
Enter configuration commands, one per line. End with CNTL/Z.
switch2(config)#interface fastEthernet 0/1
switch2(config-if)#channel-group 5 mode desirable
Creating a port-channel interface Port-channel 5
switch2(config-if)#exit
switch2(config)#interface fastEthernet 0/24
switch2(config-if)#channel-group 5 mode desirable
Creating a port-channel interface Port-channel 5
switch2(config-if)#end
I verify the configuration by checking the running config.
switch2#sh run
Building configuration...
Current configuration : 2447 bytes
!
------cut------
!
interface Port-channel5
no ip address
flowcontrol send off
!
interface FastEthernet0/1
no ip address
channel-group 5 mode desirable
!
-----cut--------
!
interface FastEthernet0/24
no ip address
channel-group 5 mode desirable
When I ping the remote switch and disconnect a cable I have no packet loss.
I also use the following useful show command to view EtherChannel information.
switch1#sh etherchannel summary
Flags: D - down P - in port-channel
I - stand-alone s - suspended
H - Hot-standby (LACP only)
R - Layer3 S - Layer2
u - unsuitable for bundling
U - in use f - failed to allocate aggregator
d - default port
Number of channel-groups in use: 1
Number of aggregators: 1
Group Port-channel Protocol Ports
------+-------------+-----------+-----------------------------------------------
5 Po5(SU) PAgP Fa0/1(Pd) Fa0/24(P)
