[OpenSIPS-Users] Calling engage_media_proxy per branch

Dan Pascu dan at ag-projects.com
Sat May 30 02:35:11 CEST 2009

On Saturday 30 May 2009, Thomas Gelf wrote:
> > engage_media_proxy doesn't terminate the media session until the dialog is 
> > destroyed.
> Hmmm... but it issues update commands (= use_media_proxy?) at each
> Re-INVITE, does it? 

It calls the equivalent of use_media_proxy for the initial INVITE, on any 
positive reply it gets (1xx and 2xx) and on the ACK, but only if there is a 
SDP body. Then it calls the equivalent of use_media_proxy on every request, 
reply, ACK within the dialog in the same manner. It calls the equivalent of 
end_media_session when the dialog is terminated (either explicitly or expires)

> And probably the dispatcher ignores them as long as there is no change to 
> active streams, correct? 

The relay will check the streams, the dispatcher has no idea what the message 
contains, it only knows to which relay to forward it. In addition, even if the 
streams do not change, the relay still has to return the IP/ports to allow the 
SDP to be modified, otherwise it won't work. So you have to do it on reINVITES 
anyway, even if they carry the same information.

> My intention was to make suggestions to improve the engage-function,
> as I've been really excited once I discovered it. Later I realized,
> that there is not everything as smooth as suggested. At least for me -
> but I thinnk others will face similar challenges.

I think you misread my point. I'm not opposed to such enhancements. It's just 
that in my use cases I have no use for them, so I'm not motivated to spend 
time to implement them. Patches are welcome though ;) (however, the changes 
need to be done in dialog and tm not in mediaproxy, so it's a larger issue to 
discuss here than enabling a mediaproxy function to work in a branch route).


More information about the Users mailing list