What what what?
Seeing that this situation has not improved at all since around 2010 when I first looked into it, I thought it would be worthwhile to write a note on an important step so often missed by vendors when implementing (IP) multicast PTP (Default profile and Enterprise profile).
I have worked with multiple complete hardware PTP implementations (appliances) that are multicast-capable: GMs, slaves, and most importantly in this context - probes, analysers and other test kit. All but very few supported sending IGMP joins or replied to IGMP querries. In my book, a multicast-capable IP stack with no IGMP support is incomplete. You all do support ICMP, do you not - or did I lose you already?
Even the fact itself that I have to explain this, should already be embarrassing to those vendors. In multiple conversations, vendor representatives otherwise well-versed in all things timing, were not quite sure what the question was. When asked if they supported sending IGMP joins or replying to IGMP queries, they would in turn ask me to spell it (as if it were some rare animal), write it down and say they would get back to me. OK, I can understand that you're a frequency guy who transitioned into the world of IP, but it's an IP world we live in, so please do your homework!