computer science

International Packet Switched Service

International Packet Switched Service is a computer 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 International Packet Switched Service rather than just read about it. In short: The International Packet Switched Service (IPSS) was the first international and commercial packet switching network. It was created in 1978 by a collaboration between Britain's Post Office Telecommunications, and the United States' Western Union International and Tymnet.

Key takeaways

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

Reference excerpt

The International Packet Switched Service (IPSS) was the first international and commercial packet switching network. It was created in 1978 by a collaboration between Britain's Post Office Telecommunications, and the United States' Western Union International and Tymnet.

History This network grew from Europe and the United States to cover Canada, Hong Kong and Australia by 1981, and by the 1990s it provided a worldwide networking infrastructure. Companies and individual users could connect in to the network, via a PSS (Packet Switch Stream) modem, or an X.25 PAD (packet assembler/disassembler), and a dedicated PSS line, and use it to connect to a variety of online databases and mainframe systems. There was a choice of about three different speeds of PSS lines, although a faster line was more costly to rent. By 1984 British Telecom had joined the PSS to the global network and was providing IPSS services to customers. Companies including Dynatech, were providers of interconnectivity and infrastructure devices including line drivers, modems, self configuring modems, 4 port, 8 port and 16 port PADs, and switches. These were physical boxes delivering full implementation of x.25, x.28, x.29 and x.3 protocols with physical connectivity conforming to RS232 asynchronous connectivity specification. JANET connections were available via IPSS. In 1988 the IPSS directory listed approximately 800 global sites available for connection via X.25. The network later adopted TCP/IP and provided infrastructure for the early Internet.

See also History of the Internet Internet in the United Kingdom Public data network

References

Sources Schatt, Stan (1991). Linking LANs: A Micro Manager's Guide. McGraw-Hill. ISBN 0-8306-3755-9.

Worked examples

Example 1 — a first encounter with International Packet Switched Service

Start with the simplest possible case. Write down what International Packet Switched Service claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer 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 International Packet Switched Service 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 International Packet Switched Service 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 International Packet Switched Service

In research: International Packet Switched Service appears in computer 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 International Packet Switched Service 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: International Packet Switched Service is common in secondary-school and first-year university syllabi. It links to neighbouring topics BT Group, Computer-related introductions in 1978, General Post Office, so understanding it makes those chapters shorter.
In everyday life: Look for International Packet Switched Service 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 International Packet Switched Service in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what International Packet Switched Service 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 International Packet Switched Service out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is International Packet Switched Service in simple terms?

Why does International Packet Switched Service matter?

Because it connects several computer 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 International Packet Switched Service?

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 International Packet Switched Service.