LACP Load share among odd number of links

[Peyman Zadmehr]

Hi

I posted a question about this case before:

https://community.cisco.com/t5/forums/replypage/board-id/5996-discussions-xr-os-and-platforms/message-id/11819

Unfortunately I could not find my answer in provided link in that post.

My scenario is this:

I have three 8x100GE cards and from each card one port is included in a L2 Ether-bundle. When I send the traffic over these three links How the traffic will be distributed? Will it be in 33% 33% 33% manner? or it will be like 25% 25% 50% ? What will happen if I have 5 links or 6 links?

Thank you

[tkarnani]

Hi Peyman,

the asr9000 does not load balance per packet, instead load balances per flow.

with real production traffic it will not be as exact as you described.

the idea will be that

flow 1, will take link 1

flow 2, will take link 2 etc

this is how the distribution per bundle member should work.

unfortunately the traffic rate is not taken into account, so it is possible that flow 1 is at a much higher rate than flow 2 so you will see some disparity in traffic rate.

the Load Balancing section of this document, has some fields/options you can use to tweak the load balancing mechanisms on bundles

https://www.cisco.com/c/en/us/td/docs/routers/asr9000/software/asr9k_r6-1/interfaces/configuration/guide/b-interfaces-cg-asr9k-61x/b-interfaces-cg-asr9k-61x_chapter_01000.html