science

Packet Radio Van

Packet Radio Van is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Packet Radio Van rather than just read about it. In short: The Packet Radio Van was a GMC Value-Van refitted by Don Cone at SRI International, and equipped with technology that was used in the first two-way internetworked transmission on August 27, 1976, and the first three-way internetworked transmission on November 22, 1977, the latter of which is considered the start of the Internet. Background The van was created as part of DARPA's PRNET project, which developed the wor…

Key takeaways

Packet Radio Van belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Packet Radio Van to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Packet Radio Van from memory before moving on to harder problems.

Reference excerpt

The Packet Radio Van was a GMC Value-Van refitted by Don Cone at SRI International, and equipped with technology that was used in the first two-way internetworked transmission on August 27, 1976, and the first three-way internetworked transmission on November 22, 1977, the latter of which is considered the start of the Internet.

Background The van was created as part of DARPA's PRNET project, which developed the world's first mobile ad hoc network. It was a mobile packet radio laboratory that housed one of the PRNET radio nodes, to simulate the needs of in-the-field military to connect to the network. As DARPA further wished to connect the disparate computers at its various contractors, and indeed globally, there was a push to test internetworking - connecting different communications protocols via the Internet protocol suite. The van played a unique role in the very first demonstration of the Internet.

Equipment The GMC van, designed by Don Cone, resembled a bread van and contained all of the equipment needed to be an ARPANET node via packet radio, including a Digital Equipment Corporation DEC LSI-11 16-bit minicomputer. Other equipment included a shielded generator, flexible equipment racks, and air conditioning. Due to his contributions around that time, Cone was promoted to Research Engineer.

Transmissions The first two-network TCP/IP transmission was between the van and ARPANET on August 27, 1976; the van was parked next to Rossotti's (since 1956, officially the "Alpine Inn"), a well-known Portola Valley, California biker bar, and wires were run to one of the picnic tables. The location was chosen as to be far enough from SRI in Menlo Park, California to be "remote" but close enough to have good radio contact. This first true Internet transmission occurred on November 22, 1977, when SRI originated the first connection between three disparate networks. Data flowed seamlessly through the mobile van at SRI in Menlo Park, California and the University of Southern California in Los Angeles via London, England, across three types of networks: packet radio, satellite, and the ARPANET. The van was also the site of the first experiments (primarily by Earl Craighill and Tom Magill) with Voice over IP through ARPA's Network Speech Compression Program around 1977 to 1978. They focused on how to compress speech such that it still sounded "natural" and arrived in a timely manner. The phone in the van was a Mickey Mouse phone.

Legacy The van was parked unused for a decade in a back lot of the SRI campus until the planning of a celebration of the 20th anniversary of the Internet in 1997 at the Internet Supercomputer Conference in San Jose, California. SRI employees Don Alves and Don Nielson cleaned, licensed, and replenished the van's radio and Internet equipment. The van was exhibited on the convention floor and was popular with attendees. SRI donated the van to the Computer History Museum to prevent further deterioration. In 2007, the Computer History Museum presented a 30th anniversary celebration of this demonstration, which included several participants of the 1977 event.

See also History of the Internet: TCP/IP

References

External links SRI Mobile Van at the Computer History Museum

Illustrations

Worked examples

Example 1 — a first encounter with Packet Radio Van

Start with the simplest possible case. Write down what Packet Radio Van claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Packet Radio Van before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Packet Radio Van ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Packet Radio Van

In research: Packet Radio Van appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Packet Radio Van in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Packet Radio Van is common in secondary-school and first-year university syllabi. It links to neighbouring topics History of the Internet, Individual cars, Packet radio, so understanding it makes those chapters shorter.
In everyday life: Look for Packet Radio Van outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Packet Radio Van in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Packet Radio Van means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Packet Radio Van out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Packet Radio Van in simple terms?

Why does Packet Radio Van matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Packet Radio Van?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Packet Radio Van.