TV over IP:A telecom triple play

Since the mid-1990s, cable TV operators have encroached on traditional telephone services initially by adding data services and then voice to their television offerings. Cable companies have used this triple play of services to woo consumers away from their local-exchange carriers—and the carriers were unable to fight back.  

While the basic ability to transmit TV signals over telephone wires has existed for some time, the service didn’t take off for two reasons: low broadband penetration and a high-cost delivery mechanism. Today, many service providers have deployed substantial broadband IP networking infrastructures, including fiber networks and xDSL-based access networks. However, a lack of applications has kept network usage modest and return on network investment low. As a result, it has become difficult to attract and retain more subscribers. Without more subscribers, service providers are hard pressed to justify the investment for more infrastructure.  

Two new developments—the availability of less-expensive delivery mechanisms and the emergence of economical television over IP (TVoIP) technology—provide a way out of this dilemma. Conditions are now ripe for carriers to turn the tables on their cable operator competitors by offering the “triple play” of voice, data and video over their existing broadband IP networks.  

More Services Than Cable

To say that TVoIP enables service providers to deliver video services that compete with cable TV is actually an understatement. The video services enabled by TVoIP are far broader and more sophisticated than those available over cable, enabling service providers not only to offer basic TV service, but also to generate new revenue streams with new services. TVoIP enables higher levels of interaction, greater schedule control and options, and more active uses of video than is possible with cable technology.  

With TVoIP, viewers can not only watch TV programs in real time, as they do with cable, but can also pause, start, stop, rewind, and fast-forward live programs or watch any previously broadcast program without having to pre-record it. TVoIP also enables video-on-demand, so subscribers can watch any pre-loaded program at any time, from anywhere. This service is far more flexible than cable TV pay-per-view or near video-on-demand services, which broadcast programs according to established schedules. Adding a video camera to the TVoIP set-top box (STB) transforms the subscriber’s home into a personal broadcasting center with videophone and videoconferencing capabilities. 

Other value-added services include personalized content/TV viewing, interactive TV, unlimited data applications, t-commerce (electronic commerce over TV), video mail, video surveillance, video network gaming, distance learning and more.  

The Basic Elements

No matter what the application, the content of TVoIP services is typically streamed from a network head-end over the backbone network to a central or regional office, where it is then distributed over the last mile to end users. A complete TVoIP solution includes at least the following five elements:

• A content creator is a head-end device that encodes or trans-codes media content into MPEG and Windows Media frames, while sending content to the streaming servers.

• Streaming servers store the content forwarded by the content creator and stream it through the broadband IP network. Each server has a control unit that tracks storage of video segments distributed among the streaming servers, accepts subscribers’ requests, redirects video segments to streaming servers, and coordinates the servers’ operations. In addition, the control unit interfaces with the management system, allowing operators to configure, monitor and control streaming servers and content creators.

• The broadband IP network that carries the media streams must provide sufficient bandwidth to support quality of service (QoS), exceeding the best-effort service provided by standard IP networks. For efficient media streaming, the network must support IP unicast and multicast, as well as IP-based streaming and control protocols. While the backbone consists of a fiber network deployed with layer-three switches, the last mile can employ any broadband method, such as DSL or FTT(x).

• The set-top box receives the compressed media stream, decodes it for display on a television screen, provides an analog interface for analog TV sets, displays an interactive Electronic Program Guide, and supports trick-mode operations based on user input. Because the compression-decompression (codec) schemes such as MPEG-4 commonly used in digital video and stereo audio applications are constantly evolving, STBs should be codec independent. Software-based STBs enable service operators to change codec standards with just a simple software download, protecting the initial STB investment. Swapping out the STBs of tens of thousands of subscribers and installing new ones every time the industry moves to a new codec technology would be a massive and very expensive undertaking.

• Middleware supports the operators’ existing operations support systems (OSSs), enabling operators to generate unified billing for voice, data and video services—and giving subscribers the convenience of paying just one bill for all the services they receive. Middleware supports such online and back office functions as media asset management (MAM), which handles media content administration and workflow management; subscriber management; channel management and scheduling; content management; customer self-service; billing; and other tasks.   

Integrated Solutions Speed Deployment

Until recently, service providers have had to buy these individual elements piecemeal and integrate them in-house. Piecemeal solutions force service providers not only to work with multiple vendors but also to handle the difficult and time-consuming job of developing the software needed to link all the different system pieces together. Depending on the complexity of the system, time to service turn-on can be anywhere from several months to years. 

Now, equipment vendors are starting to offer standards-based solutions that deliver all TVoIP components, from head-end to set-top, in a single highly integrated, highly scalable package. Solutions are essential to timely deployment of TVoIP; since these solutions are already integrated, service providers can turn on service as soon as they install them. These systems cost far less than piecemeal solutions and enable providers to deploy revenue-generating triple-play services more quickly. 

One of the challenges for attracting TVoIP subscribers will be to overcome their experience of slow or inconsistent Internet performance.

While TVoIP services can run over both ATM and IP broadband networks, the choice of which broadband technology to use can affect deployment costs. All-IP networks eliminate the expensive ATM middle layer, reduce costs and shorten return on investment. For operators considering a move from an ATM to an IP access network, some vendors offer IP solutions such as DSLAMs and FTT[x] products.

TVoIP network architecture can be centralized, distributed or a hybrid of the two, depending on the service area covered and network topology. Service providers considering an integrated solution should make sure that it supports whatever architecture they choose, since most deployments are not simply centralized or distributed.

In a centralized architecture, all content is stored in streaming servers deployed at one central site and transported to the consumer via the fiber backbone and access networks.

In a distributed architecture, the content is stored in streaming servers deployed at multiple sites, with all sites connected through a fiber-based broadband network. Video streams from the content creator are distributed to streaming servers across the whole TVoIP network. Content is duplicated to a site on demand, based on intelligent-caching algorithms.

In a hybrid architecture, as in a distributed architecture, content is stored in streaming servers located at different sites, and all servers are connected via the broadband network. However, the servers at the end of the network store only ‘hot’ content, while a server at a central site acts as an archive server containing all available content. The content server streams video to the central streaming server, and an intelligent-caching algorithm distributes content to all other sites. In this scenario, the nearest edge server serves subscribers. If the requested content is not on the edge server, it is streamed from the central archive server.

A distributed architecture ensures that there is no central point of failure; even if service to one region fails, all other regions still receive service. However, operators concerned with operating costs should compare the benefits of a distributed architecture versus a centralized architecture, which may have a lower operating cost. Some operators may opt for a hybrid approach that provides some risk reduction while still keeping operating costs down.  

Massive Scalability

Whatever the chosen architecture, any TVoIP solution must be able to scale massively to keep pace with future demand—scale in terms of number of subscribers supported, number of streams supported and content storage capacity. Many piecemeal solutions on the market today support a fixed number of subscribers, typically in the tens of thousands, forcing a service provider to purchase an entire new system if the number of subscribers increases. 

The number of TVoIP subscribers in the world is expected to reach six million by 2007, according to a 2002 report by Ovum Research. Because of these increasing numbers, service providers need highly scalable solutions for mass deployment. Scalability requires a highly parallel architecture and a load-balancing strategy to ensure there are no bottlenecks in the system. Today’s integrated solutions can scale to support 100,000 or more subscribers. 

Features such as a cluster-based server design, and modular equipment that can be expanded simply by adding blades to existing boxes, enable operators to cost effectively increase capacity proportional to system growth. Service providers can add streaming servers to meet the demand for more programs, and different types of programs, as the subscriber base increases. For example, a service provider could start by offering just broadcast television, which has no storage requirements. But, as the provider starts adding services such as video-on-demand and delayed broadcasts, it can add storage as needed. With a highly scalable solution, service providers can have thousands of terabytes of storage, which translates into millions of hours of content.  

One of the challenges for attracting TVoIP subscribers will be to overcome their experience of slow or inconsistent Internet performance. Subscribers will not tolerate TVoIP if its performance is lower than that of broadcast TV delivered over cable or satellite networks. It is therefore vital that the network supporting TVoIP services includes QoS guarantees, since broadcast-quality video signals must be given a higher priority than voice or data.

To further assure high reliability and availability, an integrated TVoIP solution should have no single point of system failure. All elements of the solution should be redundant, and backup devices should be able to take over the work of failed or problematic devices without interruption of service. The ability to distribute video content among different servers and different disks also improves service reliability, ensuring that a server or disk failure will not take all content off-line. Scalable, extensible, integrated TVoIP solutions ensure low deployment costs, whether measured per subscriber, per stream, or per hour of content storage. 

TVoIP Benefits For All

Service providers and subscribers both benefit from TVoIP. Providers benefit because they can offer a popular application that makes full use of their network resources, generates new revenue streams from existing customers and wins back customers from cable operators. Consumers benefit because TVoIP frees them from fixed program schedules and gives them greater control over which programs they watch.   

Service providers that employ an integrated TVoIP solution will receive another crucial benefit—shortened time-to-service deployment, which enables them to realize revenues more quickly and gain a competitive advantage over service providers that are slower to market. The best of the integrated TVoIP solutions incorporate all the latest industry standards for everything from transport to video. A standards-based system is much easier for system providers to integrate into their networks, operate and manage.  

Every service provider will probably offer a different mix of TVoIP services and employ a different architecture to deliver those services, and therefore experience a different return on investment. However, most providers that have implemented TVoIP find they are able to offer basic service for somewhere between $20 and $30 a month—the figure varies from country to country. Charges could climb to $50 a month, depending on the number of value-added services offered.

The basic fee is very competitive with cable TV, and many of TVoIP’s value-added services are not available over cable. The combination of cost-effective technology and winning applications will enable service providers to go head-to-head with cable operators—and win.

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David Howard is Product Manager for UTStarcom, Inc. He can be reached at dhoward@utstar.com.

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