Troubleshooting HCX Interconnect and Network Extension Issues Due to VLAN Network Loops
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Article ID: 381808
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Updated On:
Products
VMware Cloud on AWSVMware HCX
Issue/Introduction
HCX environments may experience connectivity issues affecting interconnects and network extensions, including
Network extension tunnels showing as down
Failed diagnostic tests
Loss of communication with extended VMs
IX connections failing
Cross-site connectivity disruptions
Unexplained tunnel status changes after network modifications
Common symptoms include:
Multiple service mesh connections showing down status
Diagnostic errors in HCX interface
VM communication failures across extended networks
Issues affecting multiple sites simultaneously
Problems emerging after VLAN configuration changes
Environment
VMware HCX
VLANs for HCX traffic
Cause
Several factors can contribute to this type of failure
VLAN Configuration Issues
Network loops created by improper VLAN implementation
Overlapping VLAN configurations
Incorrect VLAN tagging
Trunk configuration mismatches
Network Design Problems
Spanning tree protocol issues
Redundant paths without proper loop prevention
Missing VLAN isolation
Improper network segmentation
Implementation Errors
Incorrect VLAN assignments
Missing or incorrect trunk configurations
Layer 2 domain conflicts
Switch configuration mismatches
Resolution
Initial Assessment
Document all affected service mesh connections
Identify patterns in failed connections
Review recent network changes
Map affected sites and connections
Troubleshooting Steps
Review recently implemented VLAN configurations
Check for network loops using standard network tools
Verify VLAN trunk configurations
Examine spanning tree topology
Remediation Actions
Temporarily disable suspect VLANs to isolate issues
Verify service restoration after VLAN changes
Document working configurations
Implement corrected VLAN design if needed
Prevention Measures
Implement change control for VLAN modifications
Document successful VLAN configurations
Create testing procedures for network changes
Maintain network topology documentation
Regular review of network design
Additional Information
Best Practices
Always verify VLAN configurations before implementation
Test network changes in isolated environments when possible
Maintain detailed documentation of network topology
Implement proper change control procedures
Note: When implementing new VLANs in an HCX environment, careful consideration should be given to existing network topology and potential impact on service mesh connections. Always follow proper network design principles to prevent loops and other network issues.