RTP and H.323 for IP Telephony

RTP and H.323 for IP Telephony stacks
audio/video applications		signaling and control				data applications
video code	audio codec	RTCP	H.225 registration	H.225 Signaling	H.245 Control	T.120
RTP
UDP				TCP
IP

H.323	framework of a group protocols for IP telephony (from ITU)
H.225	Signaling used to establish a call
H.245	Control and feedback during the call
T.120	Exchange of data associated with a call
RTP	Real-time data transfer
RTCP	Real-time Control Protocol

We will not examine H.323 in much detail, but will examine RTP and RTCP.

Transcript

[slide78] So, how does it fit together into [the} protocol stack? We can see up here that we have IP with UDP and TCP on top of it. We have the media stream sitting on top of RTP with a video CODEC or audio CODEC. We have signaling carried over a protocol called RTCP, the real time control protocol associated with RTP. Or we could use another signaling and control protocol like H.225 for registration protocol, or on top of TCP, an H.225 signaling, or an H.245 control, or a T.120 for data. So a whole variety of different protocols that we can use. But in general, we're sending media on top of UDP, and we're sending the other traffic for signaling across TCP.