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