Rahul, ? if Prack is not acknowledged with 200ok, then there is no way to send it reliably through proxy servers. The 200ok tells the Prack originator and the proxies in between that the far end received it. --- On Mon, 1/9/12, rahul yadav <connect2ry at gmail.com> wrote: From: rahul yadav <connect2ry@xxxxxxxxx> Subject: Doubt about PRACK To: "pjsip list" <pjsip at lists.pjsip.org> Date: Monday, January 9, 2012, 11:49 PM hello ! rfc 3262 tells about PRACK. I didn't understand why PRACK has 200 ok though its purpose is to send acknowledgement for provisional responses ? Sorry my question is not particularly about pjsip. -thanks -----Inline Attachment Follows----- _______________________________________________ Visit our blog: http://blog.pjsip.org pjsip mailing list pjsip at lists.pjsip.org http://lists.pjsip.org/mailman/listinfo/pjsip_lists.pjsip.org -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.pjsip.org/pipermail/pjsip_lists.pjsip.org/attachments/20120113/1799f776/attachment.html>