ESXi PTP synchronization issue with IGMP snooping-enabled switches

Products

• VMware vSphere ESXi

Issue/Introduction

Symptoms:

Enabling IGMP snooping on switches can cause synchronization failure for hardware timestamping based ESXi PTP Service.

Use the below command to get status of ESXi PTP service with hardware timestamping.
~ $ esxcli system ptp stats get

Metric                      Value
--------------------------- -----
Clock Source                 ptp
Grandmaster identity         b49691.fffe.a59f4c
Interface IPv4 address
Interface IPv4 netmask
Interface operational state  up
Interface speed              25000
Master offset                0
Pin Count                    0
Port identity                b49691.fffe.a59f4c-1
Port state                   LISTENING
Transport                    udp
Uptime                       442.17

Environment

VMware vSphere ESXi 8.0.1
VMware vSphere ESXi 7.0.3
VMware vSphere ESXi 8.0.x

Cause

When IGMP snooping is enabled in the connected switch, PTP client needs to send IGMP join/leave multicast requests to receive PTP multicast stream from the grandmaster. ESXi PTP agent has a bug that prevents it from sending IGMP join/leave requests to the switch. As a result, the PTP multicast stream is not forwarded to the host, preventing proper PTP synchronization. This bug is present in ESXi 8.0 and 8.0 U1.

Resolution

VMware is aware of this issue and working to resolve this in a future release.

Workaround:
Disable IGMP snooping in your switch. Contact your switch vendor for instructions.