Simon; > "Internet Telephony" another paradox. How can the public internet > possibly support telephony? We have as axiomatic the edge-to-edge > principle which guarantees that the person at the other end may not > have UPS power supply. This is a DESIGN GOAL of the internet, hence, > the paradox. Is that design goal changing? You are talking about paradox of PSTN, then. Emergency power supply is not required directly by law. Over ISDN, emergency power supply is not required even by finer regulation and even though NTT is voluntarily supply power, it is not enough to drive an analog phone device over a TA, which is the way almost all are using ISDN. In addition, a consequence of the "end-to-end" (not "edge-to-edge") principle is fate sharing property to maximize reliability and availability, which has nothing to do with not having UPS. > The fact of the paradox is going to lead to paradoxical situations like > internet regulation for VoIP. No, not at all. It is merely that some country such as US has a paradoxical regulation on voice. > >> There is no "internet telephony"... > > > > See my paper "Simple Internet Phone" presented at INET2000. > > > > http://www.isoc.org/inet2000/cdproceedings/4a/4a_3.htm > > in the paper introduction: > > >>> However, it is obvious that the telephone network will be replaced > >>> by the Internet, > > > Why is this obviously true? It was obvious, if you have had enough knowledge on PSTN. See above. But, as the replacement is happening, it is even more obvious. > >>> of the features of VoIP protocols will become obsolete. Instead, the > >>> "Simple Internet Phone" is designed placing the priority in the > >>> affinity to the Internet and its architectural principles as an > >>> "end-to-end," "globally connected" and "scalable" IP network. > > > You do not include "reliable" or more > importantly "available" in your list of architectural principle of the > internet, Reliability and availability is automatically derived from the "end-to-end" principle. > but as I pointed out in my paradox paper, "available" is the > top principle of the telephone network. I believe that BY DESIGN the > two are mutually exclusive, thus, it is a paradox to say "internet > telephony". By design, telephone network, violating the "end-to-end" principle to have central servers, is faulty. So is MGCP, which is a major cause of loss of availability of Internet telephony or VoIP network using MGCP. > > In emergency, best effort network works better than circuit swithced > > one, of course. > > If the power goes out it doesn't matter! See above. > > As for power, have you ever used ISDN with TAs? > > No. Have more experience with PSTN. Masataka Ohta