science

MSML

MSML 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 MSML rather than just read about it. In short: The Media Server Markup Language (MSML) is used to control and invoke many different types of services on IP Media Servers and is described in RFC 5707. Clients can use it to define how multimedia sessions interact on a Media Server and to apply services to individuals or groups of users.

Key takeaways

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

Reference excerpt

The Media Server Markup Language (MSML) is used to control and invoke many different types of services on IP Media Servers and is described in RFC 5707. Clients can use it to define how multimedia sessions interact on a Media Server and to apply services to individuals or groups of users. MSML can be used, for example, to control Media Server conferencing features such as video layout and audio mixing, create sidebar conferences or personal mixes, and set the properties of media streams. As well, clients can use MSML to define media processing dialogs, which may be used as parts of application interactions with users or conferences. Transformation of media streams to and from users or conferences as well as IVR dialogs are examples of such interactions, which are specified using MSML. MSML clients may also invoke dialogs with individual users or with groups of conference participants using VoiceXML. The fundamental model with MSML is that the Media Server is an appliance that is specialized in controlling/manipulating media streams (usually RTP), and the application server is a separate unit that deals with making and breaking call connections, and controlling the application (or business) logic, so for example the application server would deal with the billing engine and logging systems. The application server establishes a control 'tunnel' (through SIP or IP), which it uses to exchange requests/responses with the media server. In the case of MSML media servers, the messages are coded in MSML, which is a control language using the syntax of XML. MSML is designed so that an application server can interact with a number of different media servers at the same time, and of course these can be distributed across a wide geography, as long as they are reachable via IP. The converse is true, that a media server can have more than one application server talking to it, so this allows for resilience to failure. MSML was originally created by Convedia (now part of RadiSys), and is an open standard, meaning that companies can use the technology without licensing intellectual property. A number of companies have adopted MSML including Intel (now Dialogic), NMS and Audiocodes. MSML covers some of the same ground as the earlier MSCML markup language (originally from Snowshore), and both languages are important references for the IETF MediaCTRL (media control) working group, that aims to standardize control of media servers. MSML creator Adnan Saleem acknowledged the MSCML had "shown the way" for driving media servers via scripting, and so a family line can be seen from MSCML through MSML to today's MediaCTRL working group at the IETF.

References

Worked examples

Example 1 — a first encounter with MSML

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

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

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

Frequently asked questions

What is MSML in simple terms?

Why does MSML 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 MSML?

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 MSML.