UPnP Universal Plug and Play

From Wikipedia-free encyclopedia. Non-** similar B ** U search.

General plug-and-play(UPnP) is a general plug-and-play Forum (UPnP)
A set of network protocols proposed by Forum. The goal of this Protocol is to make the home network (data sharing, communication and entertainment)

And various devices in the company's network can be connected seamlessly, and the implementation of related networks is simplified. UPnP controls UPnP devices based on open and Internet communication network protocol standards by defining and releasing UPnP Devices

To achieve this goal.

UPnP is derived from plug-and-play. Plug-and-play is a hot plug-and-play technology.

Overview

The UPnP system allows point-to-point connections between PCs, Internet connections, and wireless devices. It is a distributed and open system based on TCP/IP, UDP, and HTTP.

UPnP enables any two devices to communicate with each other under the management of the LAN control device. Its features include:

• The transmission media and devices are independent. UPnP technology can be applied to many media, including telephone lines, wires (Power Line Communication plc), Ethernet, infrared communication technology (IRDA), Radio (wi-fi, Bluetooth) and FireWire (1394 ). A common protocol is used instead of a task device driver.
• User Interface (UI) control. The UPnP technology allows device vendors to control devices and interact with each other through web browsers.
• The operating system and programming language are independent. Any operating system and programming language can be used to build UPnP products. UPnP does not set or restrict the application APIs running on the control device. The OS vendor can create
  Build an API that meets your customer needs. UPnP allows the vendor to control the UI and interaction of devices just like developing regular applications.
• Based on Internet technology. UPnP is built on many protocols such as IP, TCP, UDP, HTTP, and XML.
• Programming Control. The UPnP system also supports Programming Control for Conventional applications.
• Scalability. Each UPnP Device can have services related to specific devices built on the basic system.

UPnP supports Zero Configuration, "invisible network", and automatic detection. Any device can automatically join a network, obtain an IP address, and declare its name, check your own functions and other devices and their functions according to the request. DHCP and DNS services are optional and only available on the network
. The device can automatically leave the network without leaving any unnecessary status information.

UPnP is based on IP Address Resolution. Each device should have a DHCP Client and automatically search for the DHCP service when connected to the network. If the DHCP service is not found, the network is lacking.

Management Status, the device must set an address for itself. If the device obtains a domain name (for example, transmitted through a DNS server or DNS) during the interaction with the DHCP server, it should

Use this domain name in the next network operation; otherwise, the device should use its IP address.

Protocol

Found

Given an IP address, the first step in the UPnP network is discovery. When a device is added to the network, the UPnP Detection protocol allows the device to broadcast its own services to the control point. Similarly, when a control point is added to the network, it can also search for information related to devices that are interested in the network. The basic interaction between the two types is a service that only contains a small amount of important device information or related information. For example, class type, identifier, and link to more detailed information. The UPnP Detection protocol is based on the Simple Service Discovery Protocol (SSDP.

Description

The next step of UPnP network is description. When a control point detects a device, it still knows little about the device. To allow the control point to learn more about the device or interact with the device, the control point must obtain more information from the URL contained in the detection information sent by the device. The UPnP description of a device is in XML format, including the brand and manufacturer information, such as the model name and number, serial number, manufacturer name, and brand URL. The description also includes a list of embedded devices and services, as well as control, event transfer, and storage.
In the relevant URL. For each device, the description also includes a command or action list, including the Server Response parameters for various actions. These variables describe the status information of the device when it is running, the data types, ranges, and events are described.

The next step in UPnP network control is control. After a control point obtains the device description, it can send instructions to the device. To achieve this, the control point sends an appropriate control message to the service-related control URL (included in the device description ). Message control is also used through Simple Object Access Protocol (SOAP ).
XML. Similar to function calls, the service responds to control messages by returning action-related values. The effect of an action, if any, reflects the variables used to portray the running service.

Event Notification

The next step is event notification. An UPnP description includes a set of command bar tables and the amount of changes that depict the running state information. Services are updated when these variables change, and control points can be subscribed to for related changes. The Service publishes updates by sending event messages. Event messages include one or more State Information variables and their current values. These messages are also in XML format and are carried out using the universal Event Notification System (Gena ).
Format. A special initialization message is sent when the control point subscribes for the first time. It includes the variable name and value related to the service. To support coexistence of multiple control points, Event Notifications are designed to be parallel notifications for all control points. Therefore, all subscribers receive all Event Notifications equally.

Exist

The last step is to exist. If the device has an existing URL, you can use the control point to obtain information about the existence of the device. That is, you can load the URL in the browser and allow users to perform related control or view operations. Which operations are supported by pages and devices.

References

• UPnP Forum Universal Plug And
  Play Device Standards
• Golden G. RICHARD:Service
  And device discovery: protocols and Programming, McGraw-Hill Professional, ISBN
  0 to 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 to 9717861-1-9