[OpenSIPS-Users] Mediaproxy ver 2.3.4 - Conntrack meets Music on Hold

[Stuart Marsden]

sorry - email went as html

Stuart Marsden wrote:
>> 3) detect this special case and change existing conntrack to point to
>> the MoH sever, putting it back later
> Ruud Klaver wrote:
>
> How would you detect changes at SIP level in this case? The reason I'm 
> asking is because the proper way your phone should deal with this is 
> by sending a re-INVITE with the RTP endpoint of the MoH server in the 
> SDP. This should trigger mediaproxy into resetting the conntrack rule. 
> Does it currently do this, because this should already be working.
>
> Stuart wrote:
>
> The problem is the Sipura/Linksys/Cisco  Phones do it the other way 
> round - the phone going on hold  (A) sends a normal sendonly to the 
> caller(B) . Then (A) sends a brand new invite to the MoH server(C) , 
> passing what it thinks is the  SDP of the phone (B), but is actually 
> the mediarelay
>
> The 200OK SDP from the MoH sever is not used
>
> So MoH starts to send Audio to what it thinks is (A) but actually 
> sends it to (B)
>
> I can detect at the SIP level the invite to MoH (based on the TO), the 
> SDP contains the IP:Port of a valid conntrack session , so inside 
> mediaproxy would need a new method called from opensips - "update the 
> conntrack session (ignoring callid,)  using SDP IP:Port as a key"
> Ignoring the 200OK from the MoH server for now
>
> Then when the user is taken off hold the phone (A) will send a new 
> invite to undo the sendonly to (B) and drop the call to (C)
>
> Disruption to existing audio is fine as this will only happen on 
> transition to / from MoH
>
> WDYT?
>
> Stuart