Dear Tom, >OK, so at least two of us agree that DCCP SHOULD NOT generate DCCP-Data >packets on its own (zero length or otherwise) :-). :) >Therefore it seems to me that applications MAY use zero-length packets >as they see fit. The question left is "is RTP an application?" To me, >RTP has many more of the characteristics of a transport protocol than an >application, but it is consistently used over some transport protocol, >so what is it? I think this has two perspectives: 1) From the RTP's point of view, it has characteristics of a transport protocol, and infact RTP is a transport protocol for real-time applications. 2)From the underlying transport protocol which carries the RTP packets, RTP would be considered as an application layer entity? >So, the model I think that Colin has in mind for RTP over DCCP (chime in >if I get it wrong, Colin) is that a real-time application gives data to >RTP, RTP wraps that data in RTP packets and gives that to DCCP, who >wraps the RTP packets in DCCP packets. So from DCCP's point of view, >RTP is the application, and the (real) application has no way of >directly sending DCCP packets. That says that RTP MAY send zero-length >packets. True. I think so too. >One question that I still have is who is responsible for recognizing >idle and sending something? Is it the RTP stack? Or should the app >send a NOP packet that the RTP stack translates to a zero-length packet? I am trying to find answers to these questions too. Maybe Colin is the right person who can shed some light :). Regards Arjuna [snipped]
