MSML
Encyclopedia
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 stardardize control of media servers. MSML creator Garland Sharratt 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.
Internet Protocol
The Internet Protocol is the principal communications protocol used for relaying datagrams across an internetwork using the Internet Protocol Suite...
Media Servers
Media Server
A media server refers either to a dedicated computer appliance or to a specialized application software, ranging from an enterprise class machine providing video on demand, to, more commonly, a small personal computer or NAS for the home, dedicated for storing various digital media .-Purpose:By...
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
Interactive voice response
Interactive voice response is a technology that allows a computer to interact with humans through the use of voice and DTMF keypad inputs....
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
VoiceXML
VoiceXML is the W3C's standard XML format for specifying interactive voice dialogues between a human and a computer. It allows voice applications to be developed and deployed in an analogous way to HTML for visual applications. Just as HTML documents are interpreted by a visual web browser,...
.
The fundamental model with MSML is that the Media Server is an appliance that is specialized in controlling/manipulating media streams (usually RTP
Real-time Transport Protocol
The Real-time Transport Protocol defines a standardized packet format for delivering audio and video over IP networks. RTP is used extensively in communication and entertainment systems that involve streaming media, such as telephony, video teleconference applications, television services and...
), 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
Session Initiation Protocol
The Session Initiation Protocol is an IETF-defined signaling protocol widely used for controlling communication sessions such as voice and video calls over Internet Protocol . The protocol can be used for creating, modifying and terminating two-party or multiparty sessions...
or IP
Internet Protocol
The Internet Protocol is the principal communications protocol used for relaying datagrams across an internetwork using the Internet Protocol Suite...
), 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
XML
Extensible Markup Language is a set of rules for encoding documents in machine-readable form. It is defined in the XML 1.0 Specification produced by the W3C, and several other related specifications, all gratis open standards....
. 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
RadiSys
RadiSys Corporation is publicly traded company that makes embedded systems and related technology, located in Hillsboro, Oregon, United States. Founded in 1987 in Oregon by former employees of Intel, the company went public in 1995...
), 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
Dialogic Corporation
Dialogic Corporation is a designer, developer and manufacturer of communication products. It was founded in 1984 in Montreal, Canada. Dialogic products are sold worldwide through a large network of distributors and resellers, and supplied to OEMs....
), NMS and Audiocodes.
MSML covers some of the same ground as the earlier MSCML
MSCML
The Media Server Control Markup Language is a protocol used in conjunction with the Session Initiation Protocol to enable the delivery of advanced multimedia conferencing services over IP networks. The MSCML specification has been published by the IETF under RFC 4722, now obsoleted by the newer...
markup language (originally from Snowshore), and both languages are important references for the IETF MediaCTRL (media control) working group, that aims to stardardize control of media servers. MSML creator Garland Sharratt 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.