Re: RTCP sender reports - when to use?
Hi Henri! The answer is ... the RTCP channel is bi-directional even when opened to be used for A->B RTP media stream only.
If A wants to send a stream going A->B, A originates the OLC procedure. During this procedure B's RTP port, B's RTCP port and A's RTCP ports are exchanged between the sides.
For the same "kind" of media stream (such as "voice" or "video) usually B would like to send a media stream going A<-B belonging to the same H.245 session opened above. In this case B will issue OLC advertising the same B's RTCP port already used within this session.
As the result, two media unidirectional RTP channels and a single common bi-directional RTCP channel will be opened within the same H.245 session.
Best Regards, Orit Levin RADVision Inc. 575 Corporate Drive Suite 420 Mahwah, NJ 07430 Tel: 1 201 529 4300 (230) Fax: 1 201 529 3516 www.radvision.com orit@radvision.com -----Original Message----- From: henri.maenpaa@NOKIA.COM henri.maenpaa@NOKIA.COM To: ITU-SG16@MAILBAG.INTEL.COM ITU-SG16@MAILBAG.INTEL.COM Date: Thursday, September 16, 1999 5:05 AM Subject: RTCP sender reports - when to use?
Hi,
Could somebody clarify a few things for me...
Say, there's a call between A and B in H.323. RTP sessions for both stream directions are totally independent of each other, right? (except with T.120 channel a bidirectional one can be used).
Let's concentrate on RTP session where stream goes from A to B. This one RTP session is a unidirectional channel. Is the related RTCP channel also a unidirectional channel, but to opposite direction? So, if this is true, how can we use sender reports (SR) in H.323? Am I right when I assume that only way sender reports can be used in H.323 is with a T.120 bidirectional channel (when RTCP channel would probably be bidirectional also)?
Cheers, Henri
Hi Orit,
What you describe seems like the correct behaviour, is it documented anywhere, or is it a candidate for the Implementors Guide?
Regards,
Dave Walker Mitel Corporation Ontario, CANADA
Orit Levin wrote:
Hi Henri! The answer is ... the RTCP channel is bi-directional even when opened to be used for A->B RTP media stream only.
If A wants to send a stream going A->B, A originates the OLC procedure. During this procedure B's RTP port, B's RTCP port and A's RTCP ports are exchanged between the sides.
For the same "kind" of media stream (such as "voice" or "video) usually B would like to send a media stream going A<-B belonging to the same H.245 session opened above. In this case B will issue OLC advertising the same B's RTCP port already used within this session.
As the result, two media unidirectional RTP channels and a single common bi-directional RTCP channel will be opened within the same H.245 session.
Best Regards, Orit Levin RADVision Inc. 575 Corporate Drive Suite 420 Mahwah, NJ 07430 Tel: 1 201 529 4300 (230) Fax: 1 201 529 3516 www.radvision.com orit@radvision.com -----Original Message----- From: henri.maenpaa@NOKIA.COM henri.maenpaa@NOKIA.COM To: ITU-SG16@MAILBAG.INTEL.COM ITU-SG16@MAILBAG.INTEL.COM Date: Thursday, September 16, 1999 5:05 AM Subject: RTCP sender reports - when to use?
Hi,
Could somebody clarify a few things for me...
Say, there's a call between A and B in H.323. RTP sessions for both stream directions are totally independent of each other, right? (except with T.120 channel a bidirectional one can be used).
Let's concentrate on RTP session where stream goes from A to B. This one RTP session is a unidirectional channel. Is the related RTCP channel also a unidirectional channel, but to opposite direction? So, if this is true, how can we use sender reports (SR) in H.323? Am I right when I assume that only way sender reports can be used in H.323 is with a T.120 bidirectional channel (when RTCP channel would probably be bidirectional also)?
Cheers, Henri
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Dave Walker -
Orit Levin