Hello I want implement conference call to my application. Number of clients should be between 3 and 15. Maybe more. I found more documetns which describe implementation. e.g. www.cs.columbia.edu/sip/talks/sip-conferencing.pdf http://www.voxgratia.org/docs/opal/Thesis_Taha.pdf I would like use Bridge implementation. All media will be mixing on server side not on client side. But i suppose this implementation need RFC 3911 http://www.faqs.org/rfcs/rfc3911.html for JOIN signaling and RFC 3515 http://www.rfc-editor.org/rfc/rfc3515.txt for REFER method If i'm mistaken please repair me. pjsiua have RFC 3515 implementation but not RFC 3911. It's possible implement conference call without RFC 3911 ? I am new in VOIP solutions and some advice will be very helpful. Or have somebody experience with confernce calls which is not implement like bridge in pjsua? thanks