Reduced UDP traffic throughput performance through Edge Node when EDP is enabled.

Products

• VMware NSX

Issue/Introduction

• With EDP enabled, UDP throughput is less than expected.
• With EDP disabled, better UDP throughput is seen.
• UDP packets are fragmented.
• TCP is not affected and better performance is seen with TCP when EDP is enabled.
• On the Edge node, a single core may be heavily or solely utilized.

Environment

VMware NSX

Cause

NSX does not parse UDP packet headers correctly if they are fragmented and EDP is enabled. This will result in all UDP traffic flow being sent to a single vNic Rx queue.

Resolution

This is a known issue impacting VMware NSX.

There is no workaround for this issue however, where possible, attempt to limit fragmentation to avoid the problem.