introduction
This article refers to the address: http://
IPTV is the use of IP to transmit TV programs, so it is sometimes called Internet TV. But people from different industries, organizations or knowledge backgrounds have different understandings of the meaning of IPTV.
1.1 What is "TV"
The understanding of "TV" is mainly reflected in two aspects: First, the source of IPTV is consistent with the source of TV in the traditional sense; second, it is processed by a set-top box (STB), using ordinary or high-definition televisions ( TV) to do display terminals. But for these two conditions to be met at the same time, or only need to meet the first condition, it should be called IPTV, there are different understandings and definitions.
With the development of technology, the current television sets have not only been used as display terminals for television programs, but also as display terminals for other kinds of services (such as games and stock quotes). Moreover, TV programs can be viewed not only on TVs, but also on PCs and mobile phones. Therefore, the "TV" in IPTV should be defined with the content as "TV" as the core, only the program source is TV, regardless of whether the display terminal is a traditional TV. In addition, the "TV" in IPTV is no longer the "live" mode in the traditional sense.
1.2 Relationship between "IP" and "TV"
There are two perspectives on the understanding of the relationship between "IP" and "TV":
(1) "IPTV = IP + TV" mode, that is, in this implementation, IP services and TV services are completely independent and parallel in CABLE;
(2) "IPTV = TV over IP" mode, that is, all services including TV are carried on top of IP.
The understanding (or implementation) of these two methods has its own background and reasons. At least for the time being, it is not clear who understands more rationally and which way is more promising. But everyone agrees that the biggest difference between IPTV and traditional TV programs is "interactivity" and "real-time", which is an interactive network video service that can be "on-demand" whenever and wherever.
2 Benefits of developing IPTV
(1) Benefits of IPTV for content
The development of IPTV can promote the prosperity of content delivery. The IPTV industry chain is an open model. It has great appeal to content providers. Content providers can expand their content distribution channels through broadband platforms and increase the content expression and performance means. Revitalize the content inventory, so that the originally displayed idle programs can be reused by means of retrieval on-demand to improve the reuse rate of the program. At present, the content of broadband is gradually enriched, and multimedia content such as online games and Flash is in the ascendant, and providers of such content can also port their program content to IPTV. With the gradual maturity of IPTV, it will inevitably lead to the tremendous development of the content market, and will also bring huge economic benefits to content providers.
(2) The benefits of developing IPTV for business operations
In terms of business operations, IPTV is different from traditional telecommunication services. It is a three-network convergence service, and it emphasizes TV terminals while maintaining communication and online entertainment capabilities. This is an inheritance of traditional cultural consumption habits. Behind this inheritance is the consumer psychology and consumption habits of the huge user base of nearly 100 million households and the first choice of amateur entertainment. Therefore, the IPTV business has the potential to become a broadband-based business and is accepted by consumers. At present, the number of TV users in China exceeds 300 million. If TV is converted into a network terminal, even if only 20% of TV conversion is successful, there will be 60 million conversion potential, which will undoubtedly bring huge profits to business operators.
(3) The benefits of IPTV to consumers
IPTV is a new application of broadband video, which will drive the rapid development of broadband applications. People can not only get better services than traditional telecommunication services on broadband networks, but also browse the Internet, play games, and watch movies and TV programs that they want to watch. IPTV will expand broadband users from Internet users to non-Internet users, extending the broadband entertainment market from more than 22 million broadband users and more than 87 million Internet users to more than one billion TV viewers. IPTV will fundamentally change people's lives and entertainment.
(4) Benefits of IPTV to related industries
The IPTV service brings a more detailed division of labor to the industry, from content production management, business portfolio distribution, to final consumption, forming a complete industrial chain. The purpose of developing IPTV is to promote the healthy and benign development of the industrial chain, encourage enterprises in all fields to actively participate, encourage normal competition and cooperation among enterprises, promote industrial development, reduce costs, drive consumer demand, and form healthy and orderly IPTV consumption. surroundings. It will bring huge market potential to all links of the industrial chain. At the same time, since IPTV uses IP technology to carry TV services, it can provide more personalized and interactive experiences and feelings than traditional TVs on the basis of inheritance, which enables IPTV to avoid homogenous competition with traditional TV and provide differentiated services. Form the basis of benign development.
(5) Benefits of IPTV to society
IPTV is a new thing. In addition to considering its economic benefits, it must also consider the social benefits it can bring. The content of IPTV dissemination has strong ideological characteristics. Therefore, the development of IPTV is conducive to cultural communication, improving the quality of people's entertainment content, and satisfying the interests of consumers while safeguarding national interests and providing cultural guarantee for creating a harmonious society. . Therefore, it can be said that IPTV is a business that can be profitable and can spread advanced culture. The development of IPTV services has expanded the scope of network grants. Many traditional industries can be moved to the network to enable telemedicine and distance learning. It promoted the government's e-government on the Internet and greatly narrowed the digital divide between urban and rural areas, between the east and the west, between developed regions and underdeveloped regions. It has promoted the process of information civilization in the whole society.
3 Typical model of IPTV
(1) Program (content) source
It can be a production unit of various content sources, such as TV media, film and television production companies, news media organizations, distance education institutions, game producers, etc.
(2) Business platform
The content continues to be edited and integrated, providing a platform for users to provide IPTV services. The work of this platform includes the coding, orchestration, storage, distribution and management of content.
(3) Content distribution network
Responsible for passing IPTV information from the service platform to the client. This part of the work can be subdivided into two parts: "content-independent" and "content-related". The "content-independent" part includes backbone/metropolitan area networks, broadband access networks, and more. Content related parts include content distribution network (CDN), peer-to-peer (P2P) technology, and the like.
(4) Client
The main functions of the client device are: receiving (and possibly sending user requests) and processing (and possibly storing functions) the media stream to present the media stream to the user. The receiving processing device of the media can be independent of the rendering device, such as a set top box (STP) with an IP access function and a television set.
4 Telecommunications and IPTV
From the current development trend, the internal technical factors and external demand factors of the IPTV market development have basically matured. In 2005, IPTV will also usher in a more rapid development trend. In this situation, several major telecom operators and manufacturers have taken the time to move into commercial practice. China's two fixed-line operators, China Netcom and China Telecom, have already launched their own (especially with traditional TV content providers). Cooperation) Some operational practices. At the same time, a large number of traditional telecom equipment manufacturers, such as Huawei, ZTE, UT, Shanghai Bell, etc., have also invested a lot of manpower and material resources to carry out IPTV product research and development, and also put forward various unique technical solutions to prosper the market. Promote the maturity of IPTV technology.
The successful practice of telecom operators in the IPTV market has proven its indispensable position and role in the entire industry value chain. While expanding the service platform and extending the existing cooperation, telecom operators are also actively exploring how to use their broadband advantages to provide users with more and more complete services. In summary, traditional telecom operators have their own unique advantages in developing IPTV services:
(1) The broadband IP network has been developed for a long time, and the maturity of the bearer network is a necessary condition for realizing the IPTV service. IP networks naturally support point-to-point delivery, so-called interactivity, so they can be very rich in case of small changes (such as enabling support for multicast, although almost all router devices in existing telecommunication networks already support) Interactive business.
(2) Telecommunications networks, including IP networks, have always advocated a “full-process network-wide†strategy, which enables local users to truly achieve “one-point access, full-network accessâ€. It is relatively easy to implement IPTV technology on such a network.
(3) Telecom operators have accumulated years of experience in business operations, including network storage, access authentication, bandwidth management, billing and settlement, and user management. These experiences can also be used in the operation of IPTV services. Video coding technology is also constantly evolving. Now, images transmitted using MPEG-4 and H.264 encoding can achieve DVD quality requirements at a bandwidth of 800 kbit/s, thus greatly improving the service over a limited bandwidth. Quality of service. The rapid development of related network technologies, such as application layer quality control technology, CDN/VDN technology, and mature technology of controllable multicast, have paved the way for improving the quality of user services to varying degrees.
5 Conclusion
In 2004, China's information industry sales revenue has exceeded 2 trillion yuan, and the information industry has become the first pillar industry of the Chinese economy, and has become the main force driving the national industrial growth. As a basic, leading and pillar industry in China, the telecommunications industry is related to China's national security, social information and many other issues, and is related to the good operation of the entire social order. At the just-concluded "two sessions", the issue of "agriculture, rural areas and farmers" has been widely concerned by the representatives. The "village to village" project organized by the Ministry of Information Industry is being implemented, and agricultural informatization has a huge problem for solving the "three rural issues". Promote the role, so the representatives advocated communication services "three rural", making communication play a major role in solving rural distance education, cooperative medical care, cultural propaganda and other issues.
In recent years, the global telecommunications industry has been in a downturn. An important reason is that with the rapid decline of the revenue of the dominant telephone service, the data business has grown rapidly, but it can be said that no new business growth point has been found. In this situation, the practice of operators and other information industry-related enterprises in the IPTV field is looking for new business growth points, and also conforms to the development trend of the triple play, promoting the development of the communication culture industry and prospering socialism. The information services market has great significance. But IPTV is still an emerging field after all, and in reality there may be some problems:
(1) In the industrial chain, the structure is unclear, the responsibility of the content operators and the regulatory power are not clear, the strength of most links is relatively weak, and the links between the links are waiting to be fulfilled.
(2) In terms of operations, there are problems such as unclear operating mode, unclear operating entities, weak operational network capabilities, insufficient content, lack of operational motivation, and unclear tariff policies.
(3) In terms of technology and standards, there are obstacles such as inconsistent codec standards, inability to guarantee quality of service (QoS), and difficulties in interconnecting systems.
(4) In terms of policies, there are long-term supervision, market access policies are not clear, transmission security supervision, equipment access and consumer rights protection issues.
Therefore, the development of IPTV must first eliminate and strive to overcome various obstacles, strengthen the concept of competition and win-win, strengthen cooperation in all aspects of society, improve the industry chain, create new business models, prosper the entire IPTV market, and provide users with more More choices and better services meet the needs of the people's growing material and cultural life and build a harmonious society. For more information, please see what is IPTV, IPTV industry information, IPTV technology and solutions, or enter the discussion group discussion.
Fire cable type
UL flame retardant standards mainly have the following grades: CMP, CMR, CM, CMG, CMX.
1) Boost stage CMP stage (air combustion test / boost combustion test / Steiner tunnel test)
This is the highest rated Plenum Cable in the UL fire protection standard. The applicable safety standard is UL910. The test stipulated that several samples should be laid on the horizontal air duct of the equipment and burned with 87.9 kW gas burner Bunsen burner (300,000 BTU/Hr). 20 minutes. Pass criteria is that the flame must not exceed 5 feet in front of the Bunsen burner flame. The peak value of the optical density is 0.5 at the maximum, and the maximum value of the average density is 0.15.
This type of CMP cable is usually installed in a return air pressurizing system used in ventilation ducts or air handling equipment and has been approved by Canada and the United States. FEP / PLENUM materials that meet the UL910 standard have better flame retardancy than lower-smoke halogen-free materials that meet IEC 60332-1 and IEC 60332-3 standards, and have lower smoke concentrations.
2) Relay Level - CMR Level (Riser Fire Test)
This is a commercial-grade cable in the UL standard. The applicable safety standard is UL1666. The test stipulated that a plurality of samples be laid on a vertical axis of simulation, using the specified 154.5 kilowatt gas burner (527,500 BTU/Hr) for 30 minutes. Passing the standard is that the flame cannot spread to the upper part of a 12-foot-high room. The trunk cable does not have a smoke concentration specification and is typically used for floor vertical and horizontal cabling.
3) Commercial grade CM grade (vertical tray flame test)
This is a universal cable in the UL standard. The applicable safety standard is UL 1581. The test stipulated that a number of specimens should be placed on an 8-foot-high vertical stand and burned (70,000 BTU/Hr) for 20 minutes using the prescribed 20 KW band torch. By the standard, the flame should not spread to the upper end of the cable and extinguish itself. UL1581 is similar to IEC60332-3C except that the number of installed cables is different. Commercial grade cables do not have smoke density specifications and are generally only suitable for horizontal cabling on the same floor. They should not be used for vertical wiring on the floor.
4) Universal CMG (vertical tray flame test)
This is a universal cable in the UL standard. The applicable safety standard is UL 1581. Business class and common test conditions are similar, and they are also approved for use in Canada and the United States. Universal cable does not have smoke concentration specifications. They are usually applied only to horizontal cabling on the same floor and not to vertical cabling on the floor.
5) Home level - CMX level (vertical line flame test)
This is a UL standard residential cable (restricted cable). The applicable safety standards are UL1581 and VW-1. The experiment stipulated that the sample remained vertical and burned (30,000 TU/Hr) for 15 seconds with a test torch, then stopped for 15 seconds and repeated 5 times. The pass-through criteria for the remaining flame should not exceed 60 seconds and the sample should not burn more than 25%. The bottom of the surgical cotton should not be ignited by falling objects. UL1581-VW-1 is similar to IEC60332-1 except for the burning time. This grade also has no smoke or toxicity specifications and is intended for use in home or small office systems where a single cable is placed. This type of cable should not be bundled together and must have a sleeve. [1]
Low-smoke halogen-free cable (LSOH).
Low-smoke and halogen-free cables, as their name suggests, are smoke-free and halogen-free cables. The principle of low-smoke and non-halogen is that when the cable is burned in the flame, it will not produce a lot of toxic gas and smoke, so that people will not cause great casualties in the combustion, which greatly improves the people's survival rate in the fire.
The test requirements for low-smoke halogen-free cables meet three requirements:
Flame retardant requirements: Low smoke, halogen-free cables must be flame retardant. There are two flame retardant grades that are required to comply with IEC 60332.1 (vertical burning test for single cable) and IEC 60332.3C (vertical burning propagation test for bunched cable). Among them, the flame retardant requirements of IEC 60332.1 require the use of ordinary cable flame retardant requirements, while IEC 60332.3C requires relatively high flame retardant requirements at the trunk level.
Smoke Density Requirements: Smoke density tests are performed on low-smoke, halogen-free cables. It uses a fire to ignite a cable in a confined space. After the flame is extinguished, the final indoor smoke density is tested. It is required that in the presence of smoke, the light transmission capability can reach 60%. This ensures that people can see in the smoke. the way.
Toxicity requirements: There are several current toxicity testing methods, such as mouse experiments and so on. Halogen acid gas emission test (for low-halogen test) and gas acidity test (for halogen-free test) are used in the low-smoke halogen-free cable. The test principle is to determine the halogen content of the gas produced by the low-smoke halogen-free material at high temperatures (800°C and 935°C, respectively).
Some information describes the CM class requirements of IEC 60332.1 that are equivalent to UL (IEC 60332.2 is a test method for small diameter cables, that is, an alternative test method that cannot be used when testing 60332.1), and IEC 60332.3C is equivalent to UL CMR class requirements. In fact, the test methods of the four standards are not the same and cannot be directly compared.
In summary, there are two series of cables, one is the American CMX highly flame-retardant cable (the US standard clearly requires the CMX cable to contain halogen, in order to increase the temperature of the cable decomposition); the other is European FR/LSOH flame retardant/Low Smoke Zero Halogen Cable.
Folding this paragraph Fire Resistant Cable
In order to ensure the security of data, people hope that after a fire, they will have enough time to return all data before the entire network and transfer them to a safe place to minimize the possibility of data loss. Therefore, in the cable standards, there is also a type of fire protection standard called the "Line Integrity" standard. Its goal is that the cable can still keep the line open in the fire, so that the power and information can still be transmitted normally. Therefore, cables that meet the requirements for series integrity are also called fireproof cables.
At present, there are two types of common fireproof cable levels:
Chinese Standard: At 750°C, it can still work for 90 minutes (E90).
German standard: At 800-850°C, it can still work for 180 minutes (FE180).
Although the newly released China Data Center standard requires all cables to use CMP-grade integrated cable, that is, they can still be destroyed without damage at the temperature of 500°C, and the data can be transmitted normally, leaving a certain amount of time for emergency information backup. However, it does not meet the requirements of national standards for fireproof cables. It cannot be called fireproof cable.
Fire Survival Cables,Fire Fighting Cables,Fiber Optic Cable,Fire Alarm Cable
Jiangsu QiSheng Cable Co., Ltd. , https://www.shuaihe-cable.com