How to configure LACP (Link Aggregation or Ether Channel) on cisco switches


This article is all about how to configure LACP (Link Aggregation or Ether Channel) on cisco switches. The term link aggregation applies to various methods of combining (aggregating) multiple network connections in parallel in order to increase throughput beyond what a single sustain and also use to provide redundancy in case one of the links should fail. A link aggregation group (LAG) combines a number of physical ports together to make a single high-bandwidth data path.

Actually, link aggregation or Ether Channel is a technology very similar to PAgP which allows two or more than two physical ports to combine and provide a new third single logical port which results in high availability and increased bandwidth. So, now let’s start here how to configure LACP on cisco switches.

We can also configure Ether Channel on cisco switches using

1.  Static method

2.  PAgP method

Now to understand this whole process we take lab in cisco packet tracer. In this lab, we take two switches on which we configure LACP or EtherChannel.

How to configure LACP and EtherChannel on cisco switches

We do this whole lab in two parts. In the first part, we configure LACP on both the switches and in the second part we run troubleshooting commands on the switches and verify our configuration.

Now configure LACP on both the switches using below command

For switch S1

Switch>enable

Switch#configure terminal

Enter configuration commands, one per line. End with CNTL/Z.

Switch(config)#hostname S1

S1(config)#interface range fa0/1-2

 

S1(config-if-range)#channel-group 1 mode active

S1(config-if-range)#

Creating a port-channel interface Port-channel 1

%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/1, changed state to down

%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/1, changed state to up

%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/2, changed state to down

%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/2, changed state to up

S1(config-if-range)#channel-protocol lacp

S1(config-if-range)#exit

 

For switch S2

Switch>enable

Switch#configure terminal

Enter configuration commands, one per line. End with CNTL/Z.

Switch(config)#hostname S2

S2(config)#interface range fa0/1-2

S2(config-if-range)#channel-group 1 mode active

S2(config-if-range)#

Creating a port-channel interface Port-channel 1

%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/1, changed state to down

%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/1, changed state to up

%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/2, changed state to down

%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/2, changed state to up

%LINK-5-CHANGED: Interface Port-channel 1, changed state to up

%LINEPROTO-5-UPDOWN: Line protocol on Interface Port-channel 1, changed state to up

S2(config-if-range)#channel-protocol lacp

S2(config-if-range)#exit

 

Now we run troubleshooting command and verify our configuration on both the switches

For switch S1

S1#show etherchannel summary

Flags: D – down P – in port-channel

I – stand-alone s – suspended

H – Hot-standby (LACP only)

R – Layer3 S – Layer2

U – in use f – failed to allocate aggregator

u – unsuitable for bundling

w – waiting to be aggregated

d – default port

Number of channel-groups in use: 1

Number of aggregators: 1

Group Port-channel Protocol Ports

——+————-+———–+———————————————-

1 Po1(SU) LACP Fa0/1(P) Fa0/2(P)

 

For switch S2

S2#show etherchannel summary

Flags: D – down P – in port-channel

I – stand-alone s – suspended

H – Hot-standby (LACP only)

R – Layer3 S – Layer2

U – in use f – failed to allocate aggregator

u – unsuitable for bundling

w – waiting to be aggregated

d – default port

Number of channel-groups in use: 1

Number of aggregators: 1

Group Port-channel Protocol Ports

——+————-+———–+———————————————-

1 Po1(SU) LACP Fa0/1(P) Fa0/2(P)

THAT’S IT

This is the whole process by which we can easily configure LACP or EtherChannel on cisco switches. Now If you have any queries regarding this then simply solved out through the comment section and also provide feedback to us. Because your feedback is valuable for us.

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