computer science

Network Based Application Recognition

Network Based Application Recognition 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 Network Based Application Recognition rather than just read about it. In short: Network Based Application Recognition (NBAR) is the mechanism used by some Cisco routers and switches to recognize a dataflow by inspecting some packets sent. The networking equipment which uses NBAR does a deep packet inspection on some of the packets in a dataflow, to determine which traffic category the flow belongs to.

Key takeaways

Network Based Application Recognition 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 Network Based Application Recognition to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Network Based Application Recognition from memory before moving on to harder problems.

Reference excerpt

Network Based Application Recognition (NBAR) is the mechanism used by some Cisco routers and switches to recognize a dataflow by inspecting some packets sent. The networking equipment which uses NBAR does a deep packet inspection on some of the packets in a dataflow, to determine which traffic category the flow belongs to. Used in conjunction with other features, it may then program the internal application-specific integrated circuits (ASICs) to handle this flow appropriately. The categorization may be done with Open Systems Interconnection (OSI) layer 4 info, packet content, signaling, and so on but some new applications have made it difficult on purpose to cling to this kind of tagging. The NBAR approach is useful in dealing with malicious software using known ports to fake being "priority traffic", as well as non-standard applications using dynamic ports. That's why NBAR is also known as OSI layer 7 categorization. On Cisco routers, NBAR is mainly used for quality of service and network security purposes.

References

External links Network Based Application Recognition: RTP Payload Classification, Cisco. Block P2P Traffic on a Cisco IOS Router using NBAR Configuration Example, Cisco.

Worked examples

Example 1 — a first encounter with Network Based Application Recognition

Start with the simplest possible case. Write down what Network Based Application Recognition 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 Network Based Application Recognition 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 Network Based Application Recognition 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 Network Based Application Recognition

In research: Network Based Application Recognition 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 Network Based Application Recognition 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: Network Based Application Recognition is common in secondary-school and first-year university syllabi. It links to neighbouring topics Computer network security, Computer network stubs, so understanding it makes those chapters shorter.
In everyday life: Look for Network Based Application Recognition 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 Network Based Application Recognition in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Network Based Application Recognition 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 Network Based Application Recognition out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Network Based Application Recognition in simple terms?

Why does Network Based Application Recognition 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 Network Based Application Recognition?

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 Network Based Application Recognition.