Still no dice

But some more info from SIN 511 BT Wholesale TV Connect (TVC)
http://www.sinet.bt.com/511v1p0.pdf

Residential Gateway (home router) Functions [7]
• The End user Residential Gateway acts as an IGMP proxy routing agent, supports IGMP snooping and forks IGMP messages up the TV Connect and Broadband paths
• Support for IGMPv3 is required on the Residential Gateway
• The TV Connect product will only support IGMPv3 [1]
• The TV Connect product will support IGMPv3 Any Source Multicast (*,G).
• The TV Connect product will not support IGMPv3 Source Specific Multicast (S,G).

The IGMP protocol has no acknowledgements, in consequence
• Multiple IGMP requests are to be sent by the Residential Gateway. 2 IGMP requests should be sent initially (IGMPv3 default setting). The “robustness variable” setting may be adjusted if required in consultation with BT Wholesale during trials.

• The “Unsolicited report intervals” should be set to 1 second initially (IGMPv3 default setting).
• The Residential Gateway should prioritise IGMP joins and leaves upstream (802.1p marking of 3 or above)
• Responses to IGMP Queries (keep-alives) by the Residential Gateway shall only be returned over the interface through which the Queries were received.

For an end user connected via Openreach GEA (Generic Ethernet Access) (FTTC and FTTH)
• The Residential Gateway will support
– IPoE for multicast traffic and PPPoE for BB traffic
– VLAN tag ID of 0 or no VLAN tag ID for multicast and BB traffic
– Fork IGMP requests up multicast and BB paths

Is there any way you can get into the config for the ISP supplied modem? That should have details of how the bridging is set up, I think.

not without hacking it

and no I cant do that

http://huaweihg612hacking.wordpress.com/about/

http://huaweihg612hacking.files.wordpress.com/2011/11/hg612_unlock_instructions_v1-3.pdf

that's a shame I'm thinking the only way it can work if the IPTV needs a separate VLAN for multicast would be if that was set up on the modem itself and bridging through that... I think? Either that OR, does the home hub make any mention of IGMP, multicast or IPTV settings?

Well bought a 2850n

when came through the post a 2850Vn

Well set it installed 3.6.3 firmware nice and upto date, plugged the IPTV box in port 2 turned on IGMP and IGMP snooping and BANG it works !!!!

Soooooo does the 2750 do Multicast differently than a 2850 ?? looks like it as one works

lol that's awesome, I guess so! I really did not think it would be that simple after looking at all those documents haha.

Did you turn on IGMP snoop or IGMP proxy?

Given that the 2850 and 2750 have a very different firmware basis and share modem hardware only, it makes sense that one implementation would work while another wouldn't.