Link Aggregation – Part 3 (LACP Configuration on Juniper Switches) :

We have talked about LACP in the previous articles on Cisco Routers. Here we will focus on how to do this configuration on Juniper Swithes on ethernet links. As you know the protocol is the same, but there are some configuration differencies between different vendor’s devices.

By the way, we do not need to use LACP for ethernet bundlings, this is only a way with LACP protocol.

By default, there can be also maximum 8 ports in a bundle on Juniper devices. This can be changed by commands.

The typical usage of the LAG is to aggregate trunk links, between the access switch and the distribution switch.

In Juniper swithes, for aggregated links, firstly we need to configure, aggregated Etnernet interfaces.

[edit chassis]
gk@switch# set aggregated-devices interfaces device-count 1

After creating aggregated Ethernet interfaces, it is time to define minimum link count while the bundle is up. To do this use the below command:

[edit interfaces]
gk@switch# set interface-name aggregated-ether-options minimum-links 3

Lastly you can specify the link speed.

[edit interfaces]
gk@switch# set interface-name aggregated-ether-options link-speed 10g

It is time to specify the members that will be in the bundle.

[edit interfaces]
user@switch# set ge-0/0/1 ether-options 802.3ad aex

[edit interfaces]
user@switch# set ge-0/0/2 ether-options 802.3ad aex

You can also configura the vlan.

[edit vlans]
user@switch# set gklan vlan-id 20

After configuration of the aggregated ethernet interface, let’s configure the lacp protocol.

[edit interfaces]
gk@switch# set aex aggregated-ether-options lacp active

If you woldu like to check your configuration, use the below show commands under the related hierarchy:

[edit chassis]
user@switch# show
aggregated-devices {
ethernet {
device-count 1;

[edit interfaces ae0]
aggregated-ether-options {
lacp {

[edit interfaces]
user@switch# show
ether-options {
802.3ad ae0
ether-options {
802.3ad ae0

And you can also check the bundle link status with the port status by the following command.

user@switch> show interfaces terse | match ae0
ge-0/0/1.0 up up aenet –>ae0.0
ge-0/0/2.0 up up aenet –>ae0.0
ae0 up up
ae0.0 up up eth-switch

I hope this link aggregation article will be helpful for you. To learn about Alcatel-Lucent Service Router’s link aggregation, go to the next part of this article series ;)

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About the Author
Gokhan Kosem is a telecommunation engineer and a computer networks professional. His ambition to IP networks and end-to-end system installation made him to prepare this web-site. By sharing his experiences about various networking protocols beside different system installation experiences and Cisco, Juniper, Alcatel-Lucent devices configurations, he is aimed to be helpful for his collegues in all over the world. He is currently lives in Istanbul, Turkey.

2 comments for “Link Aggregation – Part 3 (LACP Configuration on Juniper Switches)”


Hi, Gokhan

This article is absolutely a good piece to get the general meaning of this concept.

I want to know why the speed was set to 10g as we have only 2 ge port validated in the AE port. This may waste your time to answer.


February 13th, 2014 at 06:02

should I give IP Address to port LAG?

August 25th, 2014 at 11:21

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