computer science

OVN

OVN 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 OVN rather than just read about it. In short: OVN (Open Virtual Network) is a system to support virtual network abstraction. OVN complements the existing capabilities of Open vSwitch to add native support for virtual network abstractions, such as virtual L2 and L3 overlays and security groups.

OVN — illustration

Key takeaways

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

Reference excerpt

OVN (Open Virtual Network) is a system to support virtual network abstraction. OVN complements the existing capabilities of Open vSwitch to add native support for virtual network abstractions, such as virtual L2 and L3 overlays and security groups.

Overview OVN is a network virtualization platform that separates the physical network topology from the logical one. Users are able to connect virtual and physical interfaces with logical switches and routers, regardless of the underlying physical topology. Users are also able to define security policies and load-balancing to these logical instances. OVN uses Open vSwitch for its switching fabric and uses tunnels to provide the logical/physical separation. Open source bindings for OVN are available for a number of platforms, such as OpenStack and Kubernetes. OVN is the software-defined networking (SDN) platform used in a number of Red Hat products, including Red Hat Virtualization, OpenStack, and OpenShift. OVN is written in platform-independent C language, which provides easy portability to various environments. The source code is licensed under the Apache License 2.0.

Features As of May 2018, features provided by OVN include the following:

Logical switches Flexible L2/L3/L4 security policies Distributed logical IPv4 and IPv6 routers Native support for network address translation (NAT), load-balancing, and DHCP L2 and L3 gateways

References

Illustrations

Worked examples

Example 1 — a first encounter with OVN

Start with the simplest possible case. Write down what OVN 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 OVN 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 OVN 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 OVN

In research: OVN 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 OVN 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: OVN is common in secondary-school and first-year university syllabi. It links to neighbouring topics Computing platforms, so understanding it makes those chapters shorter.
In everyday life: Look for OVN 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 OVN in 20 minutes

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

Frequently asked questions

What is OVN in simple terms?

Why does OVN 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 OVN?

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 OVN.

OVN