Configuring link aggregation on Cisco ASR IOS XR

Link aggregation is the process of creating a virtual interface (bundle), then adding two or more physical interfaces to the bundle. The virtual interface will have the combined data-carrying capacity of all participating links in the bundle. It is similar to etherchannel bundling created on switches. In this demonstration, I will share with us on how to bundle three links between two Cisco ASR 9010 routers to give a link capacity of 3Gbps.

Network Topology

From the network diagram above, we need to bundle the links between RouterA and RouterB to give a link with combined capacity of the three links between both routers. The individual links are 1Gigabit per second each. Our goal is to achieve a link with a data-carrying capacity of 3Gigabit per second between both routers.

Implementation

On RouterA

 

First, create the bundle interface.

 

RouterA(config)#interface Bundle-Ether1

RouterA(config-if)# description bundle_to_RouterB

RouterA(config-if)# mtu 9216

RouterA(config-if)# bundle minimum-active links 2

RouterA(config-if)# load interval 30

 

Then, add interfaces to the bundle.

 

RouterA(config)# interface GigabitEthernet0/0/0

RouterA(config-if)# description bundle_1_link_1

RouterA(config-if)# bundle id 1 mode active

RouterA(config-if)# load interval 30

RouterA(config-if)# exit

RouterA(config)# interface GigabitEthernet0/0/1

RouterA(config-if)# description bundle_2_link_1

RouterA(config-if)# bundle id 1 mode active

RouterA(config-if)# load interval 30

RouterA(config-if)# exit

RouterA(config)# interface GigabitEthernet0/0/2

RouterA(config-if)# description bundle_3_link_1

RouterA(config-if)# bundle id 1 mode active

RouterA(config-if)# load interval 30

RouterA(config-if)# exit

 

The minimun active interfaces needed for the bundle to stay up is 2. This means that as long as two physical interfaces are up on this router, the bundle will be up, provided the other end on routerB is active. The active mode used here tells the interface to actively send out Link Aggregation Control Protocol (LACP)

 

Repeat the steps on RouterB, making sure the right interfaces are selected and added to the bundle.

Verification

To verify bundle status, use the commands show bundle bundle-Ether 1, show bundle status , or show bundle trace, from the privilege mode.

 

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Timigate

Ashioma Michael, a BSc (Computer Science)., MTCNA, CCNA, and CCNP holder with many years of industry-proven experience in network design, implementation and optimization. He has tutored and guided many professionals towards obtaining their Cisco certifications. Mike works as a senior network engineer with one of the leading internet service providers in West Africa.

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