Internet 0
Encyclopedia
Internet 0 is a low-speed physical layer
Physical layer
The physical layer or layer 1 is the first and lowest layer in the seven-layer OSI model of computer networking. The implementation of this layer is often termed PHY....

 designed to route 'IP over anything.' It was developed at MIT's Center for Bits and Atoms
Center for Bits and Atoms
The Center for Bits and Atoms was established in 2001 in the MIT Media Lab at the Massachusetts Institute of Technology. The cross-disciplinary center broadly looks at the intersection of information to its physical representation....

 by Neil Gershenfeld
Neil Gershenfeld
Neil Gershenfeld is a professor at MIT and the head of MIT's Center for Bits and Atoms, a sister lab spun out of the popular MIT Media Lab. His research interests are mainly in interdisciplinary studies involving physics and computer science, in such fields as quantum computing, nanotechnology,...

, Raffi Krikorian, and Danny Cohen
Danny Cohen (engineer)
Danny Cohen is a member of the National Academy of Engineering and anIEEE Fellow . In 1993 Cohen received a USAF Meritorious Civilian Service Award....

. When it was invented, a number of other proposals were being labelled as "internet 2." The name was chosen to emphasize that this was designed to be a slow, but very inexpensive internetworking system, and forestall "high-performance" comparison questions such as "how fast is it?"

Effectively, it would enable a platform for pervasive computing -- everything in a building could be on the same network to share data gathering and actuation. A light switch could turn on a light bulb by sending a packet to it, they can be linked together by the user.

History

Internet 0 was originally a minor, expedient bit of engineering support for other MIT projects. It was intended to network buildings, improve efficiency, and gather data through the control of HVAC systems (heating, ventilation, and air conditioning).

The protocol works pretty well in a wide variety of media. The wide utility and multiple media of the protocol interested network theorists. It awakened a burst of academic papers, and started some commercial interest.

The simple, inexpensive implementation still appeals to hobbyists and students, where most of the new implementations are now (2011) found. Modern implementations are mostly software on small microcontrollers, usually with a transistor to transmit, and capacitors to isolate the transmitter and receiver. The connector literally becomes the major expense of the communication system. Such a simple, inexpensive system can be embedded into many devices to allow data retrieval or control via the Internet -- these small devices can be used to form an Internet of Things
Internet of Things
The Internet of Things refers to uniquely identifiable objects and their virtual representations in an Internet-like structure. The term Internet of Things was first used by Kevin Ashton in 1999. The concept of the Internet of Things first became popular through the Auto-ID Center and related...

.

The current largest deployment of Internet 0 was at the Venice Biennale Architecture Exhibition, in the year 2008, by a group led by the Institute of Advanced Architecture of Catalonia, directed by the architect Vicente Guallart.

Theory

The idea behind Internet 0 is to provide a general-purpose physical layer that operates well in many media. So, it's very similar to morse code
Morse code
Morse code is a method of transmitting textual information as a series of on-off tones, lights, or clicks that can be directly understood by a skilled listener or observer without special equipment...

: a general-purpose layer 1 for the Internet. Logically, this is a recursive application of the internet principle (a ubiquitous protocol) to layer 1 of the network. The pulse-position modulation of Internet 0 operates best over a segregated wire, but it works in many media. It has been tested over radio frequency
Radio frequency
Radio frequency is a rate of oscillation in the range of about 3 kHz to 300 GHz, which corresponds to the frequency of radio waves, and the alternating currents which carry radio signals...

 (RF), infrared
Infrared
Infrared light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light at 0.74 micrometres , and extending conventionally to 300 µm...

 (IR), ultrasonics, optical, DC and AC power wiring, and even physical representations such as printed bar codes and engraving on a key.

One of the main advantages of this approach is that routers become very simple. They are just a sensor, pulse reshaper and a transmitter.

Coupling the reusable physical layer to the internet protocols enables a network with very inexpensive nodes that is also addressable from the global Internet.

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
Serial Line Internet Protocol
The Serial Line Internet Protocol is an encapsulation of the Internet Protocol designed to work over serial ports and modem connections. It is documented in RFC 1055...

 (SLIP), Internet Protocol
Internet Protocol
The Internet Protocol is the principal communications protocol used for relaying datagrams across an internetwork using the Internet Protocol Suite...

 (IP), and above that, usually User Datagram Protocol
User Datagram Protocol
The User Datagram Protocol is one of the core members of the Internet Protocol Suite, the set of network protocols used for the Internet. With UDP, computer applications can send messages, in this case referred to as datagrams, to other hosts on an Internet Protocol network without requiring...

 (UDP) or more rarely Transmission Control Protocol
Transmission Control Protocol
The Transmission Control Protocol is one of the core protocols of the Internet Protocol Suite. TCP is one of the two original components of the suite, complementing the Internet Protocol , and therefore the entire suite is commonly referred to as TCP/IP...

 (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
Atmel AVR
The AVR is a modified Harvard architecture 8-bit RISC single chip microcontroller which was developed by Atmel in 1996. The AVR was one of the first microcontroller families to use on-chip flash memory for program storage, as opposed to one-time programmable ROM, EPROM, or EEPROM used by other...

 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
Personal computer
A personal computer is any general-purpose computer whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end-user with no intervening computer operator...

 that acts as a gateway
Gateway (telecommunications)
In telecommunications, the term gateway has the following meaning:*In a communications network, a network node equipped for interfacing with another network that uses different protocols....

 and firewall
Firewall (computing)
A firewall is a device or set of devices designed to permit or deny network transmissions based upon a set of rules and is frequently used to protect networks from unauthorized access while permitting legitimate communications to pass....

 to the Internet
Internet
The Internet is a global system of interconnected computer networks that use the standard Internet protocol suite to serve billions of users worldwide...

.

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.

Implementation

Internet 0 is similar to a serial port
Serial port
In computing, a serial port is a serial communication physical interface through which information transfers in or out one bit at a time...

 running at 9600 baud
Baud
In telecommunications and electronics, baud is synonymous to symbols per second or pulses per second. It is the unit of symbol rate, also known as baud rate or modulation rate; the number of distinct symbol changes made to the transmission medium per second in a digitally modulated signal or a...

 except it sends data by pulse-position modulation, and accepts up to 30% timing deviations. The medium is broadcast, and half duplex. Software in the receiving devices examines the IP address of each packet, rejecting unwanted packets.

A zero bit is a one-microsecond
Microsecond
A microsecond is an SI unit of time equal to one millionth of a second. Its symbol is µs.A microsecond is equal to 1000 nanoseconds or 1/1000 millisecond...

 pulse in the center of the first half of a bit time, and a one is a pulse in the second half of a bit time. Data is sent as 8 bit bytes. A byte is preceded by a bit time that has two pulses (at both 1 and 0 times), and ends with a bit time that has another two pulses. In some variations, the stop bit-time is optional, and the dual-pulse bit times are treated as byte separators.

The dual-pulse start and stop bit times permit a receiver to synchronize with the beginnings of bytes, and also measure the baud rate of a sender. Synchronizing on 8-bit bytes permits a 9600 baud internet-0 connection to easily translate to a standard, low-speed 19,200 baud TCP/IP serial port. The baud rate measurement permits senders and receivers to use inexpensive low-precision oscillators such as ceramic resonators or resistor-capacitor oscillators.

The most common interface uses the power supply wiring to the device. The circuit is a small surface mounted capacitor
Capacitor
A capacitor is a passive two-terminal electrical component used to store energy in an electric field. The forms of practical capacitors vary widely, but all contain at least two electrical conductors separated by a dielectric ; for example, one common construction consists of metal foils separated...

 between an AC
AC power
Power in an electric circuit is the rate of flow of energy past a given point of the circuit. In alternating current circuits, energy storage elements such as inductance and capacitance may result in periodic reversals of the direction of energy flow...

 mains wire or a DC
Direct current
Direct current is the unidirectional flow of electric charge. Direct current is produced by such sources as batteries, thermocouples, solar cells, and commutator-type electric machines of the dynamo type. Direct current may flow in a conductor such as a wire, but can also flow through...

 power wire and a single digital pin of a small microcontroller
Microcontroller
A microcontroller is a small computer on a single integrated circuit containing a processor core, memory, and programmable input/output peripherals. Program memory in the form of NOR flash or OTP ROM is also often included on chip, as well as a typically small amount of RAM...

 that switches a high-power transistor briefly on, then off. The pulses are normally generated by having software toggle a digital I/O pin on the microcontroller. They are received through another capacitor, by a microcontroller with a pin configured as an interrupt, or as a hardware timer's gate.

Commercial difficulties

While Internet 0 works in many media, for any given transmission medium there are usually competing, preexisting physical layers that are more reliable, higher speed or lower power. While they are usually not as flexible, and rarely as inexpensive, they are less surprising.

In the early exploration of the concept, Sun Microsystems
Sun Microsystems
Sun Microsystems, Inc. was a company that sold :computers, computer components, :computer software, and :information technology services. Sun was founded on February 24, 1982...

, Cisco Systems
Cisco Systems
Cisco Systems, Inc. is an American multinational corporation headquartered in San Jose, California, United States, that designs and sells consumer electronics, networking, voice, and communications technology and services. Cisco has more than 70,000 employees and annual revenue of US$...

 and Schneider Electric
Schneider Electric
Schneider Electric is a French global company. It was founded in 1836 by two brothers, Eugène and Adolphe Schneider.In the first part of the 20th century, Schneider et Cie associated itself with Westinghouse Systems, a major international electrical group at the time. The group began manufacturing...

 were interested in commercial deployment. Sun had a bankruptcy and a change of direction when it was purchased by Oracle Corporation
Oracle Corporation
Oracle Corporation is an American multinational computer technology corporation that specializes in developing and marketing hardware systems and enterprise software products – particularly database management systems...

. Cisco has decided not to deploy consumer equipment. Schneider decided to deploy Zigbee
ZigBee
ZigBee is a specification for a suite of high level communication protocols using small, low-power digital radios based on an IEEE 802 standard for personal area networks. Applications include wireless light switches, electrical meters with in-home-displays, and other consumer and industrial...

, a low-powered radio protocol.

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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