Universal Plug and Play
Encyclopedia
Universal Plug and Play (UPnP) is a set of networking protocols for primarily residential networks without enterprise class devices that permits networked devices, such as personal computers, printers, Internet gateways, Wi-Fi
Wi-Fi
Wi-Fi or Wifi, is a mechanism for wirelessly connecting electronic devices. A device enabled with Wi-Fi, such as a personal computer, video game console, smartphone, or digital audio player, can connect to the Internet via a wireless network access point. An access point has a range of about 20...

 access points and mobile devices to seamlessly discover each other's presence on the network and establish functional network service
Network service
Network services are the foundation of a networked computing environment. Generally network services are installed on one or more servers to provide shared resources to client computers.- Network services in LAN :...

s for data sharing, communications, and entertainment. The UPnP technology is promoted by the UPnP Forum
UPnP Forum
The UPnP Forum is a computer industry initiative to enable simple and robust connectivity to stand-alone devices and personal computers from many different vendors....

.

The concept of UPnP is an extension of plug-and-play
Plug-and-play
In computing, plug and play is a term used to describe the characteristic of a computer bus, or device specification, which facilitates the discovery of a hardware component in a system, without the need for physical device configuration, or user intervention in resolving resource conflicts.Plug...

, a technology for dynamically attaching devices directly to a computer, although UPnP is not directly related to the earlier plug-and-play technology. UPnP devices are "plug-and-play" in that when connected to a network they automatically establish working configurations with other devices.

Overview

The UPnP architecture allows device-to-device networking of personal computer
Personal computer
A personal computer is any general-purpose computer whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end-user with no intervening computer operator...

s, networked home appliance
Home appliance
Home appliances are electrical/mechanical machines which accomplish some household functions, such as cooking or cleaning. Home appliances can be classified into:*Major appliances, or White goods*Small appliances, or Brown goods...

s, consumer electronics
Consumer electronics
Consumer electronics are electronic equipment intended for everyday use, most often in entertainment, communications and office productivity. Radio broadcasting in the early 20th century brought the first major consumer product, the broadcast receiver...

 devices and wireless
Wireless
Wireless telecommunications is the transfer of information between two or more points that are not physically connected. Distances can be short, such as a few meters for television remote control, or as far as thousands or even millions of kilometers for deep-space radio communications...

 devices. It is a distributed, open architecture protocol based on established standards such as the Internet Protocol Suite
Internet protocol suite
The Internet protocol suite is the set of communications protocols used for the Internet and other similar networks. It is commonly known as TCP/IP from its most important protocols: Transmission Control Protocol and Internet Protocol , which were the first networking protocols defined in this...

 (TCP/IP), HTTP, 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....

, and SOAP. UPnP control points are devices which use UPnP protocols to control UPnP devices.

The UPnP architecture supports zero configuration networking. A UPnP compatible device from any vendor can dynamically join a network, obtain an IP address, announce its name, convey its capabilities upon request, and learn about the presence and capabilities of other devices. Dynamic Host Configuration Protocol
Dynamic Host Configuration Protocol
The Dynamic Host Configuration Protocol is a network configuration protocol for hosts on Internet Protocol networks. Computers that are connected to IP networks must be configured before they can communicate with other hosts. The most essential information needed is an IP address, and a default...

 (DHCP) and Domain Name System
Domain name system
The Domain Name System is a hierarchical distributed naming system for computers, services, or any resource connected to the Internet or a private network. It associates various information with domain names assigned to each of the participating entities...

 (DNS) servers are optional and are only used if they are available on the network. Devices can disconnect from the network automatically without leaving state
State (computer science)
In computer science and automata theory, a state is a unique configuration of information in a program or machine. It is a concept that occasionally extends into some forms of systems programming such as lexers and parsers....

 information.

UPnP was published as a 73-part International Standard
International standard
International standards are standards developed by international standards organizations. International standards are available for consideration and use, worldwide...

, ISO/IEC 29341, in December, 2008.

Other UPnP features include:
Media and device independence: UPnP technology can run on many media that support IP including Ethernet
Ethernet
Ethernet is a family of computer networking technologies for local area networks commercially introduced in 1980. Standardized in IEEE 802.3, Ethernet has largely replaced competing wired LAN technologies....

, FireWire, IR (IrDA
IRDA
IRDA may refer to:* Infrared Data Association, in information and communications technology , a standard for communication between devices over short distances using infrared signals...

), home wiring (G.hn
G.hn
G.hn is the common name for a home network technology family of standards developed under the International Telecommunication Union's Standardization arm and promoted by the HomeGrid Forum...

) and RF (Bluetooth
Bluetooth
Bluetooth is a proprietary open wireless technology standard for exchanging data over short distances from fixed and mobile devices, creating personal area networks with high levels of security...

, Wi-Fi
Wi-Fi
Wi-Fi or Wifi, is a mechanism for wirelessly connecting electronic devices. A device enabled with Wi-Fi, such as a personal computer, video game console, smartphone, or digital audio player, can connect to the Internet via a wireless network access point. An access point has a range of about 20...

). No special device driver
Device driver
In computing, a device driver or software driver is a computer program allowing higher-level computer programs to interact with a hardware device....

 support is necessary; common network protocols are used instead.
User interface
User interface
The user interface, in the industrial design field of human–machine interaction, is the space where interaction between humans and machines occurs. The goal of interaction between a human and a machine at the user interface is effective operation and control of the machine, and feedback from the...

 (UI) Control: UPnP architecture enables devices to present a user interface through a web browser
Web browser
A web browser is a software application for retrieving, presenting, and traversing information resources on the World Wide Web. An information resource is identified by a Uniform Resource Identifier and may be a web page, image, video, or other piece of content...

 (see Presentation below).
Operating system
Operating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...

 and programming language
Programming language
A programming language is an artificial language designed to communicate instructions to a machine, particularly a computer. Programming languages can be used to create programs that control the behavior of a machine and/or to express algorithms precisely....

 independence: Any operating system and any programming language can be used to build UPnP products. UPnP does not specify or constrain the design of an API for applications running on control points; OS vendors may create APIs that suit their customer's needs.
Programmatic control: UPnP architecture also enables conventional application programmatic control.
Extensibility: Each UPnP product can have device-specific services layered on top of the basic architecture. In addition to combining services defined by UPnP Forum in various ways, vendors can define their own device and service types, and can extend standard devices and services with vendor-defined actions, state variables, data structure elements, and variable values.

Addressing

The foundation for UPnP networking is IP addressing. Each device must implement a DHCP client and search for a DHCP server when the device is first connected to the network. If no DHCP server is available, the device must assign itself an address. The process by which a UPnP device assigns itself an address is known within the UPnP Device Architecture as AutoIP. In UPnP Device Architecture Version 1.0, AutoIP is defined within the specification itself; in UPnP Device Architecture Version 1.1, AutoIP references IETF
Internet Engineering Task Force
The Internet Engineering Task Force develops and promotes Internet standards, cooperating closely with the W3C and ISO/IEC standards bodies and dealing in particular with standards of the TCP/IP and Internet protocol suite...

 RFC 3927. If during the DHCP transaction, the device obtains a domain name, for example, through a DNS server or via DNS forwarding, the device should use that name in subsequent network operations; otherwise, the device should use its IP address.

Discovery

Given an IP address, the first step in UPnP networking is discovery. The UPnP discovery protocol is known as the Simple Service Discovery Protocol
Simple Service Discovery Protocol
The Simple Service Discovery Protocol is a network protocol based on the Internet Protocol Suite for advertisement and discovery of network services and presence information...

 (SSDP). When a device is added to the network, SSDP allows that device to advertise its services to control points on the network. Similarly, when a control point is added to the network, SSDP allows that control point to search for devices of interest on the network. The fundamental exchange in both cases is a discovery message containing a few essential specifics about the device or one of its services, for example, its type, identifier, and a pointer to more detailed information.

Description

After a control point has discovered a device, the control point still knows very little about the device. For the control point to learn more about the device and its capabilities, or to interact with the device, the control point must retrieve the device's description from the URL provided by the device in the discovery message. The UPnP description for a device is expressed in 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....

 and includes vendor-specific, manufacturer information like the model name and number, serial number
Serial number
A serial number is a unique number assigned for identification which varies from its successor or predecessor by a fixed discrete integer value...

, manufacturer name, URLs to vendor-specific web sites, etc. The description also includes a list of any embedded devices or services, as well as URLs for control, eventing, and presentation. For each service, the description includes a list of the command
Command (computing)
In computing, a command is a directive to a computer program acting as an interpreter of some kind, in order to perform a specific task. Most commonly a command is a directive to some kind of command line interface, such as a shell....

s, or actions, to which the service responds, and parameters, or arguments, for each action; the description for a service also includes a list of variables
Variable (programming)
In computer programming, a variable is a symbolic name given to some known or unknown quantity or information, for the purpose of allowing the name to be used independently of the information it represents...

; these variables model the state of the service at run time, and are described in terms of their data type, range, and event characteristics.

Control

Having retrieved a description of the device, the control point can send actions to a device's service. To do this, a control point sends a suitable control message to the control URL for the service (provided in the device description). Control messages are also expressed in XML using the Simple Object Access Protocol (SOAP). Much like function calls, the service returns any action-specific values in response to the control message. The effects of the action, if any, are modeled by changes in the variables that describe the run-time state of the service.

Event notification

An additional capability of UPnP networking is event notification, or eventing. The event notification protocol defined in the UPnP Device Architecture is known as General Event Notification Architecture (GENA). A UPnP description for a service includes a list of actions the service responds to and a list of variables that model the state of the service at run time. The service publishes updates when these variables change, and a control point may subscribe to receive this information. The service publishes updates by sending event messages. Event messages contain the names of one or more state variables and the current value of those variables. These messages are also expressed in XML. A special initial event message is sent when a control point first subscribes; this event message contains the names and values for all evented variables and allows the subscriber to initialize its model of the state of the service. To support scenarios with multiple control points, eventing is designed to keep all control points equally informed about the effects of any action. Therefore, all subscribers are sent all event messages, subscribers receive event messages for all "evented" variables that have changed, and event messages are sent no matter why the state variable changed (either in response to a requested action or because the state the service is modeling changed).

Presentation

The final step in UPnP networking is presentation. If a device has a URL for presentation, then the control point can retrieve a page from this URL, load the page into a web browser
Web browser
A web browser is a software application for retrieving, presenting, and traversing information resources on the World Wide Web. An information resource is identified by a Uniform Resource Identifier and may be a web page, image, video, or other piece of content...

, and depending on the capabilities of the page, allow a user to control the device and/or view device status. The degree to which each of these can be accomplished depends on the specific capabilities of the presentation page and device.

UPnP AV standards

UPnP AV is an audio and video extension of UPnP. On 12 July 2006 the UPnP Forum
UPnP Forum
The UPnP Forum is a computer industry initiative to enable simple and robust connectivity to stand-alone devices and personal computers from many different vendors....

 announced the release of version 2 of the UPnP Audio and Video specifications, with new MediaServer version 2.0 and MediaRenderer version 2.0 classes. These enhancements are created by adding capabilities to the MediaServer and MediaRenderer device classes that allow a higher level of interoperability between MediaServers and MediaRenderers from different manufacturers. Some of the early devices complying with these standards were marketed by Philips
Philips
Koninklijke Philips Electronics N.V. , more commonly known as Philips, is a multinational Dutch electronics company....

 under the Streamium
Streamium
Streamium is a line of IP-enabled entertainment products by Dutch electronics multi-national Philips Consumer Electronics. Streamium products allow users to consume digital entertainment and multimedia content—whether stored on their desktop computers or delivered through Internet-based services—on...

 brand name.

The UPnP AV standards have been referenced in specifications published by other organizations including Digital Living Network Alliance
Digital Living Network Alliance
The Digital Living Network Alliance is a non-profit collaborative trade organization established by Sony in June 2003, and has more than 250 member companies in the mobile, consumer electronics, PC, and service provider industries...

 Networked Device Interoperability Guidelines, International Electrotechnical Commission
International Electrotechnical Commission
The International Electrotechnical Commission is a non-profit, non-governmental international standards organization that prepares and publishes International Standards for all electrical, electronic and related technologies – collectively known as "electrotechnology"...

 IEC 62481-1, and Cable Television Laboratories
CableLabs
Founded in 1988 by cable television operating companies, Cable Television Laboratories, Inc. is a not-for-profit research and development consortium that has cable operators as its members. System operators from around the world are eligible to be members. Members dues are based on revenue...

 OpenCable
OpenCable
OpenCable is a set of hardware and software specifications under development in the United States by CableLabs to "define the next-generation digital consumer device" for the cable television industry...

 Home Networking Protocol.

Media server

A is the UPnP-server (a 'master' device) that provides media library information and streams media-data (like audio/video/picture/files) to UPnP-clients on the network. It is a computer system or a similar digital appliance that stores digital media, such as photographs, movies, or music and shares these with other devices.

UPnP AV media servers provide a service to UPnP AV client devices, so called control points, for browsing the media content of the server and request the media server to deliver a file to the control point for playback.

UPnP media servers are available for most operating system
Operating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...

s and many hardware-platforms. UPnP AV media servers can either be categorized as software-based or hardware
Hardware
Hardware is a general term for equipment such as keys, locks, hinges, latches, handles, wire, chains, plumbing supplies, tools, utensils, cutlery and machine parts. Household hardware is typically sold in hardware stores....

-based. Software-based UPnP AV media servers can be run on PC
Personal computer
A personal computer is any general-purpose computer whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end-user with no intervening computer operator...

. Hardware-based UPnP AV media servers may run on any network-attached storage
Network-attached storage
Network-attached storage is file-level computer data storage connected to a computer network providing data access to heterogeneous clients. NAS not only operates as a file server, but is specialized for this task either by its hardware, software, or configuration of those elements...

 (NAS) devices or any specific hardware for delivering media, such as a digital video recorder
Digital video recorder
A digital video recorder , sometimes referred to by the merchandising term personal video recorder , is a consumer electronics device or application software that records video in a digital format to a disk drive, USB flash drive, SD memory card or other local or networked mass storage device...

 (DVR). As of May 2008, there were more software-based UPnP AV media servers than there were hardware-based servers.

Other components

  • UPnP MediaServer ControlPoint - which is the UPnP-client (a 'slave' device) that can auto-detect UPnP-servers on the network to browse and stream media/data-files from them.
  • UPnP MediaRenderer DCP - which is a 'slave' device that can render (play) content.
  • UPnP RenderingControl DCP - control MediaRenderer settings; volume, brightness, RGB, sharpness, and more).
  • UPnP Remote User Interface (RUI) client/server - which sends/receives control-commands between the UPnP-client and UPnP-server over network, (like record, schedule, play, pause, stop, etc.).
    • Web4CE (CEA 2014) for UPnP Remote UI - CEA-2014 standard designed by Consumer Electronics Association
      Consumer Electronics Association
      The Consumer Electronics Association is a standards and trade organization for the consumer electronics industry in the United States. The Consumer Electronics Association is the preeminent trade association promoting growth in the $173 billion U.S...

      's R7 Home Network Committee
      . Web
      Web page
      A web page or webpage is a document or information resource that is suitable for the World Wide Web and can be accessed through a web browser and displayed on a monitor or mobile device. This information is usually in HTML or XHTML format, and may provide navigation to other web pages via hypertext...

      -based Protocol and Framework
      Software framework
      In computer programming, a software framework is an abstraction in which software providing generic functionality can be selectively changed by user code, thus providing application specific software...

       for Remote User Interface on UPnP Networks and the Internet
      Internet
      The Internet is a global system of interconnected computer networks that use the standard Internet protocol suite to serve billions of users worldwide...

       (Web4CE). This standard allows a UPnP-capable home network device to provide its interface
      User interface
      The user interface, in the industrial design field of human–machine interaction, is the space where interaction between humans and machines occurs. The goal of interaction between a human and a machine at the user interface is effective operation and control of the machine, and feedback from the...

       (display and control options) as a web page
      Web page
      A web page or webpage is a document or information resource that is suitable for the World Wide Web and can be accessed through a web browser and displayed on a monitor or mobile device. This information is usually in HTML or XHTML format, and may provide navigation to other web pages via hypertext...

       to display on any other device connected to the home network. That means that you can control a home networking device through any web-browser
      Web browser
      A web browser is a software application for retrieving, presenting, and traversing information resources on the World Wide Web. An information resource is identified by a Uniform Resource Identifier and may be a web page, image, video, or other piece of content...

      -based communications method for CE devices
      Consumer Electronics Association
      The Consumer Electronics Association is a standards and trade organization for the consumer electronics industry in the United States. The Consumer Electronics Association is the preeminent trade association promoting growth in the $173 billion U.S...

       on a UPnP home network using ethernet
      Ethernet
      Ethernet is a family of computer networking technologies for local area networks commercially introduced in 1980. Standardized in IEEE 802.3, Ethernet has largely replaced competing wired LAN technologies....

       and a special version of HTML
      HTML
      HyperText Markup Language is the predominant markup language for web pages. HTML elements are the basic building-blocks of webpages....

       called CE-HTML
      CE-HTML
      CE-HTML is a language for creating user interface pages for Consumer Electronics devices such as televisions. These CE-HTML pages are typically placed online and are based on a 10-foot user interface for easy control from a distance. It is profiled on XHTML and associated standards with special...

      .
  • QoS (Quality of Service) - is an important (but not mandatory) service function for use with UPnP AV (Audio and Video). QoS (Quality of Service)
    Quality of service
    The quality of service refers to several related aspects of telephony and computer networks that allow the transport of traffic with special requirements...

     refers to control mechanisms that can provide different priority to different users or data flows, or guarantee a certain level of performance to a data flow in accordance with requests from the application program. Since UPnP AV is mostly to deliver streaming media
    Streaming media
    Streaming media is multimedia that is constantly received by and presented to an end-user while being delivered by a streaming provider.The term "presented" is used in this article in a general sense that includes audio or video playback. The name refers to the delivery method of the medium rather...

     that is often near real-time or real-time audio/video data which it is critical to be delivered within a specific time or the stream is interrupted. QoS (Quality of Service)
    Quality of service
    The quality of service refers to several related aspects of telephony and computer networks that allow the transport of traffic with special requirements...

     guarantees are especially important if the network capacity is limited, for example public networks, like the internet
    Internet
    The Internet is a global system of interconnected computer networks that use the standard Internet protocol suite to serve billions of users worldwide...

    .
    • QoS (Quality of Service)
      Quality of service
      The quality of service refers to several related aspects of telephony and computer networks that allow the transport of traffic with special requirements...

       for UPnP consist of Sink Device (client-side/front-end) and Source Device (server-side/back-end) service functions. With classes
      Class (computer science)
      In object-oriented programming, a class is a construct that is used as a blueprint to create instances of itself – referred to as class instances, class objects, instance objects or simply objects. A class defines constituent members which enable these class instances to have state and behavior...

       such as; Traffic Class that indicates the kind of traffic in the traffic stream, (for example, audio or video). Traffic Identifier (TID) which identifies data packets as belonging to a unique traffic stream. Traffic Specification (TSPEC) which contains a set of parameters that define the characteristics of the traffic stream, (for example operating requirement and scheduling). Traffic Stream (TS) which is a unidirectional flow of data that originates at a source device and terminates at one or more sink device(s).
  • Remote Access - defines methods for connecting UPnP device sets that are not in the same multicast domain.

NAT traversal

One solution for NAT traversal
NAT traversal
NAT traversal is a general term for techniques that establish and maintain Internet protocol connections traversing network address translation gateways. Network address translation breaks end-to-end connectivity. Intercepting and modifying traffic can only be performed transparently in the...

, called the Internet Gateway Device Protocol (IGD Protocol), is implemented via UPnP. Many routers and firewall
Firewall (computing)
A firewall is a device or set of devices designed to permit or deny network transmissions based upon a set of rules and is frequently used to protect networks from unauthorized access while permitting legitimate communications to pass....

s expose themselves as Internet Gateway Devices, allowing any local UPnP control point to perform a variety of actions, including retrieving the external IP address of the device, enumerate existing port mappings, and add or remove port mappings. By adding a port mapping, a UPnP controller behind the IGD can enable traversal of the IGD from an external address to an internal client.

Future developments

UPnP continues to be actively developed. In the fall of 2008, the UPnP Forum ratified the successor to UPnP 1.0, UPnP 1.1. See for documents describing the published standard.

The DPWS
Devices Profile for Web Services
The Devices Profile for Web Services defines a minimal set of implementation constraints to enable secure Web Service messaging, discovery, description, and eventing on resource-constrained devices....

 standard was a candidate successor to UPnP, but UPnP 1.1 was selected by the Forum.

The UPnP Internet Gateway Device (IGD) standard has a WANIPConnection service that contains a competing solution known as NAT-PMP
NAT Port Mapping Protocol
NAT Port Mapping Protocol is an Internet Engineering Task Force Internet Draft, introduced by Apple Computer as an alternative to the more common Internet Gateway Device Standardized Device Control Protocol implemented in many network address translation routers. It was introduced in June 2005...

, which is an IETF draft introduced by Apple Inc. in 2005. However, NAT-PMP is focused only on NAT traversal. Version 2 of IGD is currently under development; additional details are available from.

See also

  • Comparison of UPnP AV media servers
  • Devices Profile for Web Services
    Devices Profile for Web Services
    The Devices Profile for Web Services defines a minimal set of implementation constraints to enable secure Web Service messaging, discovery, description, and eventing on resource-constrained devices....

  • Digital Living Network Alliance
    Digital Living Network Alliance
    The Digital Living Network Alliance is a non-profit collaborative trade organization established by Sony in June 2003, and has more than 250 member companies in the mobile, consumer electronics, PC, and service provider industries...

     (DLNA)
  • List of UPnP AV media servers and clients
  • UPnP AV media server
  • Zeroconf
    Zeroconf
    Zero configuration networking , is a set of techniques that automatically creates a usable Internet Protocol network without manual operator intervention or special configuration servers....


Books

  • Golden G. Richard: Service and Device Discovery : Protocols and Programming, McGraw-Hill Professional, ISBN 0-07-137959-2
  • Michael Jeronimo, Jack Weast: UPnP Design by Example: A Software Developer's Guide to Universal Plug and Play, Intel Press, ISBN 0-9717861-1-9

External links


Documentation


News

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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