Subscription aging

[Earlyriser]

I noticed that after a while my home grown control point stops getting events from subscribed services:

/Ds/Ds/event
/Ds/Playlist/event
/Ds/MediaTime

Is there something that must be done to ensure that the DS knows that the control point has not gone away - that it is still interested in events even if quite a bit of time has passed?

A short description of how the DS decides to remove defunct control point subscriptions would be really helpful (maybe failed HTTP NOTIFY requests, absence of SSDP adverts, idle time or ?)

TIA
Sean

[grahamd Linn Staff]

When you subscribe, the Upnp device tells you how long your subscription lasts. You have to renew before it expires in order to maintain it. It is usual to renew half way through the subscription period to ensure constant service. Please refer to the Upnp specification for details on how to renew a subscription and, in fact, for an authoratitive specification of subscription in general.

The DS removes subscription because:

i) Unsubscribe request
ii) Subscription expired
iii) On sending an event to a subscriber the subscriber gives an HTTP response code other than 200.

Graham

[Earlyriser]

I never thought to read the spec! I should try that more often ;-)

Thanks very much for the pointer and the DS criteria.

Sean

(whose daily professional life is reverse engineering bizarre and buggy 'standardised' mobile phone XML interfaces with no documentation!)

[grahamd Linn Staff]

Hey Sean, out of interest, what language/OS/development environment are you using?

Graham

[Earlyriser]

A bit of a hobby project... Some of the prototype code is in Erlang (http://www.erlang.org). Strange telecoms language designed for protocol design - makes life extremely quick and easy to build anything that has to communicate.

All development is done on a Mac - I was never able to come to terms with Windows after version 3.1!

Sean