<div dir="ltr"><div style="box-sizing:border-box;color:rgb(37,36,36);font-family:"Segoe UI","Helvetica Neue",Helvetica,Arial,sans-serif;font-size:14px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial">Hi list, </div><div style="box-sizing:border-box;color:rgb(37,36,36);font-family:"Segoe UI","Helvetica Neue",Helvetica,Arial,sans-serif;font-size:14px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial">I'd like to know if there's a way to tell FS to wait for RTP reception before sending any RTP packet ? </div><div style="box-sizing:border-box;color:rgb(37,36,36);font-family:"Segoe UI","Helvetica Neue",Helvetica,Arial,sans-serif;font-size:14px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial">We're facing a problem regarding early media with a PBX, NATed behind a dumb router : actually, if FS first sends RTP to the PBX, without waiting for RTP coming from the PBX, there's no audio. In some cases (related to the provider we use behind FS to establish call to the PSTN) FS isn't the 'first-shooter' of the RTP flow, and everything works fine, but when FS is the first to send RTP, it doesn't work... </div><div style="box-sizing:border-box;color:rgb(37,36,36);font-family:"Segoe UI","Helvetica Neue",Helvetica,Arial,sans-serif;font-size:14px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial"><div style="box-sizing:border-box">Because we can't change anything at our providers configs, we'd like to know if FS can "delay" RTP sending until it receives some RTP from the calling party.</div><div style="box-sizing:border-box"> </div><div style="box-sizing:border-box">The schematic is following :</div><div style="box-sizing:border-box">PBX ===> FS ===> ...voice backbone... ===> Providers</div><div style="box-sizing:border-box">(FS is acting as an SBC)</div><div style="box-sizing:border-box"> </div><div style="box-sizing:border-box">Thanks for your help, </div></div><br></div>