[VMC on AWS] Intermittent connectivity issues between VMs in the same segment

Products

• VMware Cloud on AWS

Issue/Introduction

To understand the cause and remediation steps with respect to this issue.

Symptoms:

For the VMs experiencing connectivity issues:

• Traffic between VMs within the SDDC(East-West) may be intermittently impacted
• Traffic between VMs in SDDC and a destination outside the SDDC(North-South) may be intermittently impacted

Cause

• Intermittent connectivity issues between VMC in the same segment are seen if the VMs are connected to a segment which is using more than the supported number of logical/virtual ports per logical segment: 2048 per logical segment as of SDDC of version 1.22
  • 
• Please refer to the official Configuration Maximums for VMware Cloud on AWS to confirm the Limits for specific SDDC versions: VMware Configuration Maximum tool
• Navigating to VIEW STATISTICS of the associated segment will show the packet drops (In the Transmitted Packets section)
  • 

Resolution

• Create a plan to change of network topology to reduce the number of ports per segment to a supported value (2048 per logical segment - 4000 across the entire SDDC)
• Since these changes may require a network downtime, the suggestion is to perform the same during a maintenance window

Additional Information

• VMware Configuration Maximum tool
• Create or Modify a Network Segment

Impact/Risks:

• Applications running in the VMs which are sensitive to packet drops will get impacted.
• The proposed remediation step may result in network downtime.