design and implement a new protocol for dial-up analog modem

[Peter Xu]

All,

I would appreciate it if you could provide me help or comments on this:
design and implement a new protocol for dial-up analog modems, the new
protocol will replace TCP/IP protocols.

My specific questions are:

1. In V.34 or V.90 modems, is the IP protocol built on the PPP
(Point-to-Point Protocol)? If not, what is the data link protocol?

2. The new protocol has the following requirements:
a. all the packets have a fixed length: 72 bytes,
b. it is for point-to-point connection only,
c. it can re-transmit a packet if errors are detected by CRC.
As you can imagine, if I use TCP/IP protocols, its overhead will use up all
bytes. Since the protocol is for point-to-point only, I am thinking to
design a protocol that does not include IP address or MAC address in the
packet format. So I could cut the overhead dramatically. Is this realistic?

3. How much work is involved to implement such a protocol?

4. Do similar protocols exist?

Thank you very much,

Peter Xu

[Art Jackson]

Modems are just a transport device for data, zeros and ones. The modem
doesn't care what format or protocol the data is in, it simply passes
the data from one end to the other in either direction. Actual commands
to establish the modem end to end connection, are sent to the modem
using ASCII. Once the connection is established, the modem switches to
data mode. Many devices, such as telemetry, remote monitoring, etc, use
modems to transmit their data from end to end. The only requirement for
the data is that the receiving end recognizes and decodes the data into
useful information/indications. Good luck.

--
Art Jackson W4TOY Owensboro, KY USA
Life is God's open book test. In order to pass,
you must open His book to find the answers.