[fusion_text]EtherChannel is a technology that allows you to aggregate multiple physical links of the same capabilities into a single logical one. In this way you can increase the bandwidth of a particular connection mitigating bottlenecks.
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.
Access Global Configuration mode
Access Interface Configuration mode.
Change the switchport to trunk or access, but all ports must be in the same VLAN, speed, duplex, etc.
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
To verify the port-channel is configured, use the following command:
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
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.
Shell
1 | Linuxsource_Switch1> enable |
Shell
1 | Linuxsource_Switch1# configure terminal |
Shell
1 | Linuxsource_Switch1(config)# interface range fastethernet 0/1-2 |
Shell
1 2 3 4 | 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 |
Shell
1 2 3 4 5 6 7 | 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 |
Shell
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 | 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 |
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.
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