BT routers only support igmp v2 if you enable it ... its typically disabled by default. (finding it in the advanced settings may take some digging.. look for multicast / multicast routing. )
Its more likely however the Pc is acting as the controller and has a firewall, and the firewall is either filtering the igmp packets (check in and out rules) or has stealth mode (or equivalent ) enabled.
https://en.wikipedia.org/wiki/Internet_Group_Management_Protocol
On 7 Mar 2016, at 04:37, James Courtier-Dutton <james.dutton@???<
mailto:james.dutton@gmail.com>> wrote:
Hi,
IGMP is part of the multicast protocol. Generally, it tends to be filtered, so will not work across the internet. My guess is that the home hub does not support it, but a normal switch should support it. If it is a smart switch, you might need to go into the config and spacifically enable multicast.
Kind regards
James
On 6 Mar 2016 18:42, "Roger Munford" <rogermunford@???<
mailto:rogermunford@parussoftware.co.uk>> wrote:
I have a problem with a new, complex system for managing ethernet connected solar inverters and the problem may well be down to missing multicasts from a BT home hub.
The German manufacturers insist there is nothing wrong but do not have any ideas. It is likely that there is a handful of similar setups working in the UK but not this one.
The system consists of 3 solar inverters and a controller that is connected with a switch which is also connected to the local network and ultimately the internet. The inverters and the controller connect to the company server and upload data. There is a local configuration programme which runs on a PC and connects to each of the inverters. Everything works as expected network wise.
The system has a "heartbeat" so that each inverter gets a message every second to continue. If the message does not arrive the inverter automatically shuts down and this is this function that is not working.
Buried in the documentation I found the following: "For the correct function ..... all network devices used must support the IGMP protocol, minimum
required version 2. (IGMP V2)"
I had to look up IGMP having not come across it before. I originally thought that the heartbeat signal comes from the controller and so only the switch should be required to support IGMP. I couldn't find any reference in the switch documentation but assumed that a brand new switch would support it. I tried two other switches that were to hand and had the same results.
My latest thought is that the heartbeat may actually come over the internet from the company server. That would mean that the network router would have to support the IGMP protocol. The network router is an oldish BT home hub. This thought has just occurred and I cannot get at it to look because it is some miles away.
For anybody that has followed what I have been trying to describe, do BT Home hubs support IGMP? is there something in the configuration that enables/disables it and is there a test that I can do to verify it?
Thanks for your patience, I hope the above was relatively clear.
Roger
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