[mythtv-users] Upnp, dlna, interval Upnp updates on multicast 239.255.255.250 port 1900

[David Blain]

> [Ole Rydahl:]
> Thanks! You have got a point! I did the following test - setting up a
Windows
> media player on a xp-system and some dlna on top. Its services are
> recognized immediately after power cycling the TV-set!
> 
> Guess I'll have to power up Wireshark and record in detail why the
behaviors
> differ!
> 
> Oh dear - barking up two wrong trees during just one evening! ...
> 
> Thanks again!!

Like others have said, the upnp control point should perform an M-SEARCH and
Mythbackend should answer.  Mythbackend also, per the upnp spec, advertises
it's availability using multicast.  The advertisement is marked to expire
the default amount of time of 60 minute.  And according to the spec, it
re-advertises 1/2 that time (which explains why you see it every 30
minutes).

It can be changed by modifying/adding an entry to the settings table.  The
key is "UPnP/SSDP/MaxAge"  and is in seconds.

FYI: the line that uses it is: 

	m_nMaxAge      = UPnp::g_pConfig->GetValue( "UPnP/SSDP/MaxAge" ,
3600 );

in upnptasknotify.cpp.

David.