Introduction and simple guide of Ether-channel with practical example using packet tracer

What Is Ether-channel | Redundancy links play a very important role in network architecture. But  when we are going to establish redundant links between switch for redundancy stp prevents the looping link between the switch therefore we can not establish redundant links between switches .we can utilize all links using ether channel.

Concept of Ether-channel

STP prevents the layer2 looping between switches.

Suppose we have two switches (switch0 and switch1).switch0 is connected to switch1 by 3 fast Ethernet links for redundancy purpose. If stp is active between two switches  two links are blocked for prevent the layer2 loop.we only get one link between two switches.

That means we get 100mbps link instead of 300mbps link. To utilize 300 mbps link we have to create port channel through which we can get efficient bandwidth.

Advantage of Ether-channel

After establish the ether channel there are many advantages:

·         Load balancing is possible between the switches  as there is three redundant links.

·         If one physical  link is failure communication is still establish for the other redundant  links.

Type of Protocol

Two protocols are there.

·         PAGP: Developed by cisco and using two mode one is auto and other is desirable.

·         LACP: Open standard Protocol  and there is also two mode one is active and other is passive.

Configuration of Ether-channel

Suppose we have two switches (switch0 and switch1).switch0 is connected to switch1 by 3 fast Ethernet links for redundancy purpose. If stp is active between two switches  two links are blocked for prevent the layer2 loop which is identified by red ink.

Ehter-channel

On switch1 we run one command to check the blocking port :

Switch#show spanning-tree active

Interface Role Sts Cost Prio.Nbr Type

---------------- ---- --- --------- -------- --------------------------------

Fa0/1 Root FWD 19 128.1 P2p

Fa0/2 Altn BLK 19 128.2 P2p

Fa0/3 Altn BLK 19 128.3 P2p

Here we found that state of  Fa0/2 and Fa0/3  port is block.

Now we are going to create ether channel using LACP .

We go to  interface configuration mode using the below command:

Switch(config)#interface range fastEthernet 0/1 - fastEthernet 0/3

Switch(config-if-range)#channel-protocol lacp

Switch(config-if-range)#channel-group 1 mode active

After execute these above commands port channel 1 is created and three redundant link will be active.We can verify all active ports using the following command:

Switch#show spanning-tree active

Interface Role Sts Cost Prio.Nbr Type

---------------- ---- --- --------- -------- --------------------------------

Po1 Root FWD 8 128.27 Shr

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