Requirements
The design intent is to provide a simple, very inexpensive system that can transmit data slowly over many types of media, and yet still connect devices to the internet. Connecting to the internet is a crucial part of the design, because much of the value of a networked device is provided by easy, wide access to it. The higher layers of an Internet 0 network are usually Serial Line Internet Protocol (SLIP), Internet Protocol (IP), and above that, usually User Datagram Protocol (UDP) or more rarely Transmission Control Protocol (TCP).
The protocol layers are chosen to need a minimum of code, to keep the expense of the computer low. Internet 0 has been implemented in small AVR microcontrollers. In most existing implementations, the layers are not distinct, because small code is more important than elegant design.
A small translation device normally attaches a local network of Internet 0 devices to the serial port of a PC that acts as a gateway and firewall to the Internet.
Devices can talk directly to each other without requiring a server. The distributed architecture ensures that there is no central point of failure.
Address assignment and cryptographic key initialization is sometimes performed by closing a contact on the device while having a master controller broadcast an assignment message. Security is via a simplified encryption system.
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