How to configure and remove EtherChannel

What is Ether Channel?

An EtherChannel provides a fault-tolerant, high-speed link between switches, routers, and servers. You can use an EtherChannel to increase the bandwidth and provide fault tolerance anywhere in the network where bottlenecks are likely to occur. EtherChannels provide automatic recovery for the loss of a link by redistributing the load across the remaining links. All links that are part of the channel share the same Layer 2 (MAC) address and Layer 3 (IP) address, and as such, individual link status changes are transparent to the network applications and its users.


How many types for EtherChannel?

There are two types EtherChannels: layer 2 etherchannel and layer 3 etherchannel

For Layer 2 EtherChannels:

• Assign all ports in the EtherChannel to the same VLAN, or configure them as trunks. Ports with different native VLANs cannot form an EtherChannel.
• If you configure an EtherChannel from trunk ports, verify that the trunking mode (ISL or 802.1Q) is the same on all the trunks. Inconsistent trunk modes on EtherChannel ports can have unexpected results.
• An EtherChannel supports the same allowed range of VLANs on all the ports in a trunking Layer 2 EtherChannel. If the allowed range of VLANs is not the same, the ports do not form an EtherChannel even when Port Aggregation Protocol (PAgP) is set to the auto or desirable mode.
• Ports with different spanning-tree path costs can form an EtherChannel if they are otherwise compatibly configured. Setting different spanning-tree path costs does not, by itself, make ports incompatible for the formation of an EtherChannel.

For Layer 3 EtherChannels, assign the Layer 3 address to the port-channel logical interface, not to the physical ports in the channel. 

In CCIE Wireless Lab, we need Layer 2 EtherChannel.


How config, remove, and show EtherChannel

Step 1: Creating a Port Channel

  switch# configure terminal  
  switch (config)# interface port-channel 1 

  To remove the port channel:

  switch(config)# no interface port-channel channel-number 

Step 2: Adding a Port to a Port channel
  

  switch# configure terminal 

  switch (config)# interface ethernet 1/4 

  switch(config-if)# switchport trunk encapsulation dot1q

  switch(config-if)# switchport mode trunk  
  switch(config-if)# channel-group 1 mode on

  To remove the port from the channel group: 
  switch(config)# no channel-group

  
Step 3: Show

  switch# show etherchannel summarys
  switch# show etherchannel load-balance



http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3750x_3560x/software/release/12-2_55_se/configuration/guide/3750xscg/swethchl.html
 
Catalyst 3560-E Switch Software Configuration Guide, 12.2(55)SE: www.cisco.com/en/US/docs/switches/lan/catalyst3750x_3560x/software/release/12.2_55_se/configuration/guide/swethchl.html