Configure Etherchannel

You cannot connect the 2 cables in the picture below, because it will create an network loop, or STP is enabled and one
link will disabled automatically. Cisco uses the term PAgP and other industry standards uses LACP.
How to configure it on Cisco switches:Connect to te switch by SSH, Telnet or console port and access the privileged EXEC mode.

Linuxsource_Switch1> enable

Access Global Configuration mode

Linuxsource_Switch1# configure terminal

Access Interface Configuration mode.

Linuxsource_Switch1(config)# interface range fastethernet 0/1-2

Change the switchport to trunk or access, but all ports must be in the same VLAN, speed, duplex, etc.

Linuxsource_Switch1(config-if-range)# switchport mode access
Linuxsource_Switch1(config-if-range)# switchport access vlan 10
Linuxsource_Switch1(config-if-range)# channel-group 4 mode desirable
Linuxsource_Switch1(config-if-range)# end

On the second switch, you should apply the following configuration. Only the channel-group used on this switch is different. Different port groups are allowed because it is simply a local (to the switch) configuration to keep each port group uniquely identified. Many IT administrators do keep the channel-group numbers the same because by matching the port group numbers on either end of the connection, you can avoid confusion for others

Linuxsource_Switch2> enable
Linuxsource_Switch2# configure terminal
Linuxsource_Switch2(config)# interface range fastethernet0/1 -2
Linuxsource_Switch2(config-if-range)# switchport mode access
Linuxsource_Switch2(config-if-range)# switchport access vlan 10
Linuxsource_Switch2(config-if-range)# channel-group 5 mode auto
Linuxsource_Switch2(config-if-range)# end

To verify the port-channel is configured, use the following command:

Linuxsource_Switch2# show etherchannel port-channel
Channel-group listing:
                ----------------------
Group: 2
----------
                Port-channels in the group:
                ---------------------------
Port-channel: Po2
------------
Age of the Port-channel   = 00d:00h:08m:12s
Logical slot/port   = 2/2       Number of ports = 2
GC                  = 0x00000000      HotStandBy port = null
Port state          = Port-channel 
Protocol            =   PAGP
Port Security       = Disabled

Ports in the Port-channel:
Index   Load   Port     EC state        No of bits
——+——+——+——————+———–
0     00     Fa0/1    Automatic          0
0     00     Fa0/2    Automatic          0
Time since last port bundled:    00d:00h:03m:56s    Fa0/2
In the chart below you will find the Etherchannel Modes

Mode	Protocol	Description
Auto	PAgP	Sets the interface to respond to PAgP negotiation packets, but the interface will not start negotiations on its own.
Desirable	PAgP	Sets the interface to actively attempt to negotiate a PAgP connection.
On	Etherchannel	Forces the connection to bring all links up without using a protocol to negotiate connections. This mode can only connect to another device that is also set to on. When using this mode, the switch does not negotiate the link using either PAgP or LACP.
Active	LACP	Sets the interface to actively attempt to negotiate connections with other LACP devices.
Passive	LACP	Sets the interface to respond to LACP data if it receives negotiation requests from other systems.