EtherChannel

EtherChannel is a port link aggregation technology developed by Cisco, which provides fault-tolerant high-speed links between Switches, Routers, and Servers. EtherChannel technology allows multiple physical Ethernet links (Fast EtherNet or Gigabit Ethernet) to combine into one logical channel.

There are two protocols used for negotiating EtherChannel and Link Aggregation. We can configure EtherChannel in three ways in Cisco Switches.

Port Aggregation Protocol (PAgP) – Cisco Proprietary protocolIEEE Link Aggregation Control Protocol (LACP) – Industry StandardManual Etherchannel Configuration – Without using any negotiation protocol listed above

Port Aggregation Protocol (PAgP) is a Cisco proprietary protocol. Therefore Port Aggregation Protocol (PAgP) can be used to negotiate EtherChannels only between Cisco switches.

Follow these steps to configure EtherChannel using Port Aggregation Protocol (PAgP) in Cisco Switches. The ports which are going to be in EtherChannel must be in the shutdown state while configuring the EtherChannel to prevent loops and other related problems.

Switch mytech.com.SW1

mytech.com.SW1>mytech.com.SW1>enablemytech.com.SW1#configure terminalEnter configuration commands, one per line. End with CNTL/Z.mytech.com.SW1(config)#interface range gigabitEthernet 0/1 - 2mytech.com.SW1(config-if-range)#channel-group 1 mode desirablemytech.com.SW1(config-if-range)#channel-protocol pagp mytech.com.SW1(config-if-range)#exitmytech.com.SW1(config)#exitmytech.com.SW1#

Switch mytech.com.SW2

mytech.com.SW2>mytech.com.SW2>enablemytch