Hi Sec 5.1 of RFC 3264 clearly states that:
Once the offerer has sent the offer, it MUST be prepared to receive media for any recvonly streams described by that offer. It MUST be prepared to send and receive media for any sendrecv streams in the offer, and send media for any sendonly streams in the offer (of course, it cannot actually send until the peer provides an answer with the needed address and port information). In the case of RTP, even though it may receive media before the answer arrives, it will not be able to send RTCP receiver reports until the answer arrives. This should also apply to a UAS while generating Offer in 18x/200 response for INVITE received without SDP. The RTP port must be opened to receive RTP if the stream is offered as recvonly or sendrecv, as soon as the response containing offer is sent. Peer can start sending RTP to this port as soon as knows the UAS's willingness to listen and has opened it's media channel. Regards Rohit Aggarwal Aricent -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Elison Niven Sent: Tuesday, September 09, 2008 4:07 PM To: [email protected] Subject: [Sip-implementors] More on when to open rtp listen port Hi, Now if I receive an INVITE without an SDP, I send the offer in the 200 OK. So should I open the listen port before or after receiving the ACK? If I do so after receiving the ACK, there are chances that a few ICMP packets may be sent back to the first few received RTP. So should I open the rtp listen port on sending 200 OK or on receiving the ACK in this case? Best Regards, Elison _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors "DISCLAIMER: This message is proprietary to Aricent and is intended solely for the use of the individual to whom it is addressed. It may contain privileged or confidential information and should not be circulated or used for any purpose other than for what it is intended. If you have received this message in error,please notify the originator immediately. If you are not the intended recipient, you are notified that you are strictly prohibited from using, copying, altering, or disclosing the contents of this message. Aricent accepts no responsibility forloss or damage arising from the use of the information transmitted by this email including damage from virus." _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
