Only 2 ports out of 3 are being used for traffic in LACP

[vpaus]

HI,

I have LACP setup between a 3500 series and a 2000 series switch; even though I am using 3 ports in LACP, when i run the show interface port command i can see data traffic only flowing through 2 of my ports. Even in that it is showing me that 1 port is used at 100% of its capacity while the second one is used at 75% of its capacity and third one is only using 0.5% of avialable bandwidth

I am thinking maybe i might have to turn off MSTP instance between the LACP link but i am not sure how to carry it out or whether it would work or not, any advice ?

[vpaus]

I changed the trunk load balancing behaviour from default (L3-based) to L4-Based. It has made some difference but still 1 port is being over utilised.

port 1 - 93%

port2 - 27%

port 3 - 53%

[drk787]

@vpaus Hi, Yes changing the load balancing method is a good option. Please refer the below URL which explains as how the traffic is distribued across trunk links.

https://techhub.hpe.com/eginfolib/networking/docs/switches/WB/15-18/5998-8162_wb_2920_mcg/content/index.html 

[parnassus]

Hi, it's pretty normal to experience some egressing traffic "polarization" against a particular physical port (of an aggregated link = your Port Trunk logical interface): distribution depends not only by the Load Balancing algorithm used but also it depends on the source/destination traffic type (L4 helps better than L3 to distributed across Port Trunk's member ports...but still...the less variance on src/dst you have - in terms of IP/Ports/Protocol - the worst the distribution is...at a point that one or more ports can be hitten more than others.

[vpaus]

For multicast traffic to transverse through the trunk link are there any specific commands that i should be using on the trunk links.