Just as the Internet will continue to bring people together and provide individualized services like never before, the IP network technology that enables broadband media services is rapidly improving and becoming more powerful. This section of the broadband media services tutorial will provide an overview of the network and component technology required for end-to-end broadband media services provision, as well as an overview of technology standards involved in digital multimedia content creation and transmission.
Next-Generation Networks
In a truly mobile information society, mobility, traditional fixed and mobile-network services, value-added services, and the Internet are all combined to offer seamless services for end-users. As uniform services will be available through different access points and optimized for each device (TV, PC, wireless device, etc.), seamless roaming among multiple access devices will be required. Users won’t have to be concerned with the underlying technologies used, but they will be concerned with being able to access the same services wherever they are and whenever they choose.The Next-generation network, the first truly data-oriented broadband network supporting broadband media services, will be all IP, meaning all access to the network will occur via IP standards. The evolution of the broadband media services network can be characterized by six different transitions:
- Transition from a dial-up-like circuit-switched network to a data-oriented network
- Transition from connectivity to service-creation platforms
- Transition from a copper-based network towards an all-optical network
- Convergence of fixed networks
- Convergence of mobile and fixed networks
- Transition to IP version 6 (Ipv6) networks
In short, next-generation networks will evolve to better reflect the requirements of broadband media services. In practice this means bringing IP and other associated network functionalities in the network closer to the customers. The DSL technology and network components that enable high-speed IP access and basic broadband media services exist today, and will remain the foundation of the next-generation broadband media services network:
The major components of a broadband IP access network and next generation broadband media services network are
- high-speed DSL access multiplexers (DSLAM) equipment, located in the operator central 0ffice (CO) and/or in remote locations close to end-users
- broadband access servers
- DSL modems in the home and/or office providing fixed local-area networks (LAN) and wireless LAN (WLAN) network access
- Network- and service-management and provisioning products
- loop management for managing DSL services in the local telecom loop
- IP network security and authentication products for network security and user identification
In addition to network infrastructure, network services will manage and enhance the physical network for broadband media services delivery. Broadband media services network integration services could include network capacity planning and business consulting for network optimization and interoperability, network installation setup and field-testing trials, customer-service support and training, and network validation and certification services.
Components
With the IP access network as a foundation, broadband media services–specific network enhancements are required. The broadband media services components can have varied functionality with just a minor change in the presentation of the feature, which is required for a modular and scalable solution as new services are created and consumer demand for additional services evolves. Essentially, broadband media services allows consumers to customize their viewing via network control devices. Each set of devices or “boxes” can support a unique content lineup map, which enables consumers to select and pay for only the media that interest them. Specific standards mentioned, such as moving pictures expert group (MPEG), are described in greater detail in the “Standards” section, and specific services, such as voice on demand (VOD), will be described in the “Services” section.
Video Encoders
Video encoders are devices that create digital video. Input to the encoders can be analogue video or a Digital Video Broadcasting Group (DVB) multiplex. Both are required because some video content will be statically loaded from video tapes and some content will be captured from a satellite (DVB) multiplex. Video encoders that are used to deliver broadband media services most often allow for the creation of MPEG content and have the ability to support IP multicast at varying bit rates, as well as the ability to decrypt video streams to remove conditional access.
Video Servers
Video servers perform two major functions. First, they act as content repositories for the material being streamed. Second, they are responsible for streaming out video and audio using the desired format and network protocol. Video servers can be scaled from streaming 20 to over 5,000 simultaneous video streams. Video servers generally support several different transport protocols for video delivery.
Interactive Television Application
Interactive TV (ITV) applications consist of many different applications. The core of the system is the application framework and the data-handling capabilities of the back-end systems. Highly scalable for add-on features, the fundamental applications in an ITV system are customer relationship management (CRM) software modules that track customer usage, profiles, buying characteristics, and application subscription information and create billing events that-can be exported to various billing systems. Applications that typically run on the application framework are VOD, time-shifted TV, web access integrated with video applications, e-mail, personalized user interfaces, broadcast multichannel TV, and pay-per-view applications. Variants of these fundamental applications include channel blocking; parental controls; instant web access associated with viewing preferences for an enhanced, interactive viewing experience; video special offers; and targeted advertising.
Set Top Box and Customer Premises Equipment
The set top box and customer-premises equipment (CPE) are devices that are placed in consumer homes or offices, either as two separate devices or as one device combining the home or office gateway functionality required for broadband media services delivery to fixed and wireless devices. A set top box is an electronic device that serves as an interface between a television set and a broadband network, providing VOD and interactive multimedia services. CPE is any type of network device that sits in the home or office of the consumer, as opposed to the central network office or remote sites. User connections to broadband media services are made through modems and media terminals in the home and office, while the main infrastructure lies in the back-end networks, invisible to the end-user.
Standards
To help ensure the interoperability, modularity, and flexibility of services, network, content, and service providers are driving towards open standards for individual broadband media services. Standards forums meet regularly to enhance existing standards, incorporate new technological developments into current standards, agree on next steps for testing, and anticipate new developments that will affect standards. Some of the standards involved in broadband media services areIP
This is a standard supported by major application providers, software companies, and computer manufacturers. Since the range and variety of broadband media applications are more important with respect to commercial revenue-bearing services than any one specific application, enabling the integration of a broad range of media services and applications, IP is crucial. Without IP as a unifying protocol, the set of applications could be limited. One of the features of broadband media services is that it takes full advantage of the guarantees provided by IP access products with respect to real-time IP data delivery. The network provides real-time guaranteed IP data delivery. This clearly removes the burden of bandwidth management off the consumer applications and enables the developers of consumer applications to focus on the usability issues as well as providing an enriched user experience. IP provides the path that allows applications to evolve, independent of the transport protocols selected for broadband delivery.
IPv6
This is the new IP to replace the current version, IP version 4 (IPv4). IPv6 has been designed to meet the challenges of the growing Internet and includes several improvements over IPv4. The main benefits of IPv6 include a larger address space, integrated security, support for auto-configuration of terminals, and support for mobility.
MPEG
This is a digital video and audio compression format that was defined as part of the International Standards Organization (ISO). MPEG is a compression method that uses interframe compression. Interframe compression assumes that although something is happening in the foreground, the background in most video frames remains the same. This means that it is not necessary to compress each entire frame, but only the differences between them.
MPEG–2
MPEG–2 is a widely used, standardized video coding and compression technology. MPEG–2 is used in DVD movies and digital satellite distribution. Non-compressed video stream is roughly 200 Mbps, but with MPEG–2 the video can be encoded at 1.5–18 Mbps. DVD quality can be reached between 5–9 Mbps, but 2–3 Mbps is enough to exceed VHS quality. MPEG–4 is also a video coding and compression technology.
MPEG–4
MPEG–4 is a compression/decompression technology that aims to achieve interactivity, efficiency, and stability in transmissions. The result of another international effort involving hundreds of researchers and engineers from all over the world, MPEG–4 offers higher video quality and resolution at a lower data rate than MPEG–2. Also, the MPEG–4 stream encoding rate range is wider (5 kbps–60 Mbps). MPEG–4 allows interactive objects in the stream, making it more multimedia ready. On a broader level, MPEG–4 aims to pave the way toward a uniform, high-quality encoding and decoding standard that would replace the many proprietary streaming technologies in use on the Internet today. MPEG–4 is also designed for low bit-rate communications devices, such as wireless mobile devices that can display video. MPEG–4 supports scalable content, which means content is encoded once and automatically played back and transmitted at different rates depending on the available network connection.
Real-Time Streaming Protocol (RTSP)
This defines the control interface between video server and video client. With RTSP, the end user can control the video server as he or she would control the home VCR (play, pause, fast forward, rewind, etc.) RTSP also initiates the video streams and identifies different streams in the network so that the information can be used in billing.
Internet Group Management Protocol (IGMP)
This is a protocol that supports IP multicasting, a method of broadcasting that authenticates end-users prior to receiving content.
Very High Bit Rate Digital Subscriber Line (VDSL)
This is an extremely high-speed DSL technology for transmitting digital information over short reaches of an existing phone line to homes and businesses. With VDSL, transmission rates are very dependent upon actual loop length. The maximum downstream rate is between 51 and 55 Mbps over lines up to 1000 ft (300 meters) in length. Initial upstream rate will be an asymmetric rate between 1.6 and 2.3 Mbps. The data channel will be a separate frequency than that of bands used for plain old telephone service (POTS) and integrated services digital network (ISDN), thus enabling service providers to overlay VDSL onto existing services. As needs arise for higher-speed upstream rates, VDSL may need echo cancellation. Easy Transaction through payday advance
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