Re: [Sip-implementors] Duplicate RTP streams with same source IP address and Port number
Paul, Thanks for your response. Yes. This is media associated with a single 5-tuple negotiated via a single m-line SDP. - ramesh On 5/23/2017 8:31 PM, Paul Kyzivat wrote: Ramesh, On 5/22/17 3:00 PM, Ramesh Kuppili wrote: SIP Gurus, I have a situation where I am receiving multiple RTP stream from the same IP address and port number. But with different SSRC. The media in the both streams is the same (audio, more precisely ringback tone). How should I handle this scenario. 1. Should I accept one stream and ignore the other. If so, which stream should I prefer. 2. Should I mix both the streams and play on the endpoint. I am almost certain that mixing both the audio streams will result in undesirable ringback like tone. Is there a any standard that specifies how I should handle this case. Any pointers in this regard is really appreciated. I'm not an expert in media processing, but I'll try to provide some context. First can you confirm that you are talking about media associated with a single 5-tuple negotiated via a single m-line in SDP? Historically SIP didn't talk about this. In the primary usage for simple VOIP I think the expectation has been that only a single RTP stream will used at any one time. But that stream may change over time. (For instance when transitioning from in-band ringback to media from the callee.) So I think it has been fairly typical to simply play out what is received without regard to SSRC. However more advanced uses of SIP have used multiple SSRCs. There was never any formal prohibition against doing this, but because there was no standardization about how it should be processed there have been no guarantees of interoperable behavior when doing so. Some of the other people who post here can probably give you better advice on how best to cope when receiving from multiple SSRCs. More recently there has been explicit work to standardize such usage. In particular: https://tools.ietf.org/html/draft-ietf-mmusic-sdp-bundle-negotiation-38 This results in using multiple m-lines, each describing an RTP stream but all sharing the same 5-tuple. Presumably that isn't your case. Thanks, Paul ___ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/sip-implementors ___ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
Re: [Sip-implementors] Duplicate RTP streams with same source IP address and Port number
Ramesh Kuppili writes: > I have a situation where I am receiving multiple RTP stream from the > same IP address and port number. But with different SSRC. The media in > the both streams is the same (audio, more precisely ringback tone). How > should I handle this scenario. Here is one complication: Your system probably doesn't know when this scenario is happening and when it is not happening, because your system probably doesn't want to expend the effort to recognize when "The media in the both streams is the same". Thus, in practice, the question is, "I am receiving multiple RTP stream from the same IP address and port number. But with different SSRC. What should I do in this situation, such that in the specific case when I receive the same media (ringback tone) via both SSRCs, there is still a good user experience." Actually, if your system is receiving two copies of the same media under different SSRCs, I would say that the sending system is malfunctioning. The typical implementation during an early dialog is to mix all incoming audio streams. In addition, if one of the early dialogs is ringing (has returned a 180 Ringing status but not a 199 Early Dialog Terminated) and no non-silence audio is being received from that endpoint, the implementation adds a locally-generated ringback tone to the mix. Dale ___ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
Re: [Sip-implementors] Duplicate RTP streams with same source IP address and Port number
Ramesh, On 5/22/17 3:00 PM, Ramesh Kuppili wrote: SIP Gurus, I have a situation where I am receiving multiple RTP stream from the same IP address and port number. But with different SSRC. The media in the both streams is the same (audio, more precisely ringback tone). How should I handle this scenario. 1. Should I accept one stream and ignore the other. If so, which stream should I prefer. 2. Should I mix both the streams and play on the endpoint. I am almost certain that mixing both the audio streams will result in undesirable ringback like tone. Is there a any standard that specifies how I should handle this case. Any pointers in this regard is really appreciated. I'm not an expert in media processing, but I'll try to provide some context. First can you confirm that you are talking about media associated with a single 5-tuple negotiated via a single m-line in SDP? Historically SIP didn't talk about this. In the primary usage for simple VOIP I think the expectation has been that only a single RTP stream will used at any one time. But that stream may change over time. (For instance when transitioning from in-band ringback to media from the callee.) So I think it has been fairly typical to simply play out what is received without regard to SSRC. However more advanced uses of SIP have used multiple SSRCs. There was never any formal prohibition against doing this, but because there was no standardization about how it should be processed there have been no guarantees of interoperable behavior when doing so. Some of the other people who post here can probably give you better advice on how best to cope when receiving from multiple SSRCs. More recently there has been explicit work to standardize such usage. In particular: https://tools.ietf.org/html/draft-ietf-mmusic-sdp-bundle-negotiation-38 This results in using multiple m-lines, each describing an RTP stream but all sharing the same 5-tuple. Presumably that isn't your case. Thanks, Paul ___ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
Re: [Sip-implementors] Duplicate RTP streams with same source IP address and Port number
Hi Ramesh, RFC 3550, Section 8 could help: If a receiver discovers that two other sources are colliding, it MAY keep the packets from one and discard the packets from the other when this can be detected by different source transport addresses or CNAMEs. Br, Somesh :--) -Original Message- From: sip-implementors-boun...@lists.cs.columbia.edu [mailto:sip-implementors-boun...@lists.cs.columbia.edu] On Behalf Of Ramesh Kuppili Sent: Tuesday, May 23, 2017 12:30 AM To: sip-implementors@lists.cs.columbia.edu Subject: [Sip-implementors] Duplicate RTP streams with same source IP address and Port number SIP Gurus, I have a situation where I am receiving multiple RTP stream from the same IP address and port number. But with different SSRC. The media in the both streams is the same (audio, more precisely ringback tone). How should I handle this scenario. 1. Should I accept one stream and ignore the other. If so, which stream should I prefer. 2. Should I mix both the streams and play on the endpoint. I am almost certain that mixing both the audio streams will result in undesirable ringback like tone. Is there a any standard that specifies how I should handle this case. Any pointers in this regard is really appreciated. Thanks in advance. - ramesh ___ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/sip-implementors ___ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
