Is UPnP a rubish protocol ???

[simoncn]

If a device drops off after approximately 30 minutes, this is because UPnP "alive" messages are being blocked by your network. This is very commonly caused by IGMP snooping being enabled but not configured correctly. It is quite difficult to configure IGMP snooping correctly, so the best solution for most people is to disable IGMP snooping. This means you need a router that can do this, either by default or with a configuration option.