RTEP Connectivity Lost alarm in NSX Manager

Products

• VMware NSX

Issue/Introduction

Title: Alarm for rtep_connectivity_lost
Event ID: rtep_connectivity_lost
Alarm Description:

• Purpose: RTEP Connectivity is Lost
• Impact: Inter-site networking for the gateway will not work.

Environment

VMWare NSX
VMWare NSX-T Data Center

Cause

This alarm is raised when an edge node loses connectivity with a particular site.

Resolution

Steps to resolve
For VMware NSX-T Data Center 3.0.2 and higher

Resolve RTEP Connectivity issue.

Maintenance window required for remediation? No

Additional Information

1. RTEP VLAN and MTU Mismatch:
   1. Check RTEP VLAN by logging to NSX and navigating to System | Fabric | Nodes | Select Relevant TN | Tunnels | RTEP VLAN and check RTEP MTU by navigating to System | Fabric | Settings | MTU Configuration Check
      
      
   2. Alternatively, you can use the NSX API to check the RTEP parameters
      
      Invoke NSX API GET API to check RTEP MTU
      GET/remote/{remote_site_id}/api/v1/global-configs/SwitchingGlobalConfig
      
      Invoke NSX API POST API to fetch RTEP VLAN for particular Transport Node
      POST /remote/{remote_site_id}/api/v1/search/aggregate?page_size=250 
      Sample request body for above POST API
      {"primary":{"resource_type":"TransportNode","filters":[{"field_names":"id","value":"{transport_node_id}}","case_sensitive":true}]},"related":[]}
      
      
   3. Check VLAN and MTU config for the TOR interface connected to the physical NIC of the DVS uplink which provides connectivity for RTEP.
      MTU config should be as high as the physical infrastructure supports.
      Use MTU pings to verify the MTU supported by physical infrastructure. From the edge, use a command similar to the following to do this by giving the MTU in the packet size:
      ping <RTEP_IP_of_remote_site> repeat <count> size <packet_size> dfbit ENABLE vrf <REMOTE_TUNNEL_VRF ID>
   4. Verify that external firewalls are not blocking ICMP, BGP between the RTEPs.
      ICMP "Fragmentation Needed" messages should be enabled on the TOR or intermediate nodes between the RTEPs.
      RTEP VLAN should match the TOR VLAN.