What you have described is a relatively complex networking issue which most likely require a deeper investigation than the back and forth of posts in the community board. What Meraki support have described isn't inaccurate. TCP retransmits can definitely lead to performance degradation. However, it is a symptom of the issue, not the cause. If you know the issue is specifically when the MS425 is involved, I suggest following the path of a specific test and capture at all points. It should become pretty clear that there is either: - Packets missing from one of the captures (Eg. dropped packets) - Large delays in packets seen in one of the captures Based on that, you should be able to trace the point of where the issue is. The next step would be to investigate whether it's congestion/oversubscription, faulty hardware, MTU mismatch etc. Additionally, you've identified a lot of MAC flapping. I suggest investigating which ports MAC's are flapping between and the cause of that.
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