Internet TV
A telco IPTV service is usually delivered over a complex and investment heavy walled garden network, which is carefully engineered to ensure bandwidth efficient delivery of vast amounts of multicast video traffic. The higher network quality also enables easy delivery of high quality SD or HD TV content to subscribers’ homes. This makes IPTV by default the preferred delivery platform for premium content. However the investment for a telco to build an end-to-end IPTV service can be substantial.
By contrast "Internet TV" generally refers to transport streams sent over IP networks (normally the Internet) from outside the network that connects to the users premises. An Internet TV provider has no control over the final delivery and so broadcasts on a "best effort" basis. Elementary streams over IP networks and proprietary variants as used by websites such as YouTube are now rarely considered to be IPTV services.
Compared to telco IPTV, Internet TV is a quick-to-market and relatively low investment service. Internet TV rides on existing infrastructure including broadband, ADSL, Wi-Fi, cable and satellite which makes it a valuable tool for a wide variety of service providers and content owners looking for new revenue streams. However, due to the fact that IPTV is always delivered over low cost IP STBs, which have limited computing power, the capability for IPTV operators to provide diverse multimedia services is limited. This is where Internet TV has an advantage as it is delivered to a subscriber's (generally) powerful PC.
The relative ease of establishing an Internet TV service seems at first a threat to telco IPTV operators’ multimillion dollar investment, but both services do not necessarily compete for the same customers and there are some synergies between the two such as a common technology platform in the form of web-based technologies for content storage and delivery.
Broadcast IPTV has two major architecture forms: free and fee based. As of June 2006, there are over 1,300 free IPTV sources available. This sector is growing rapidly and major television broadcasters worldwide are transmitting their broadcast signal over the Internet. These free IPTV sources require only an Internet connection and an Internet enabled device such as a personal computer, HDTV connected to a computer or even a 3G cell/mobile phone to watch the IPTV content. Various Web portals offer access to these free IPTV sources. Some cite the ad-sponsored availability of TV series such as Lost as indicators that IPTV will become more prevalent.
Because IPTV uses standard networking protocols, it promises lower costs for operators and lower prices for users. Using set-top boxes with broadband Internet connections, video can be streamed to households more efficiently than current coaxial cable. ISPs are upgrading their networks to bring higher speeds and to allow multiple High Definition TV channels.
IPTV uses a two-way digital broadcast signal sent through a switched telephone or cable network by way of a broadband connection and a set-top box programmed with software (much like a cable or DSS box) that can handle viewer requests to access to many available media sources.
Local IPTV, as used by businesses for Audio Visual AV distribution on their company networks is typically based on a mixture of: a) Conventional TV reception equipment and IPTV encoders b) IPTV Gateways that take broadcast MPEG channels and IP wrap them to create multicast streams.
Architecture of a Video Server Network
Depending on the network architecture of the Service Provider, there are two main types of Video Server architectures that can be considered for IPTV deployment, Centralized, and Distributed.
The Centralized Architecture model is a relatively simple and easy to manage solution. For example, as all contents are stored in Centralized servers, it does not require a comprehensive content distribution system. Centralized Architecture is generally good for a network that provides relatively small VOD service deployment, has adequate core and edge bandwidth and has an efficient Content Delivery Network (CDN).
A Distributed Architecture is just as scalable as the Centralized model, however it has bandwidth usage advantages and inherent system management features that are essential for managing a larger server network. Operators who plan to deploy a relatively large system should therefore consider implementing a Distributed Architecture model right from the start. Distributed Architecture requires intelligent and sophisticated content distribution technologies to augment effective delivery of multimedia contents over service provider's network.
Key Areas of an End-to-End IPTV id Technology Solution
When considering deploying a telco IPTV service, understanding the technical implications of delivering the solution should be of paramount importance. Within the overall technical parameters of an IPTV service rollout, there are four key areas that need to be addressed to ensure a robust and scalable service delivery: content distribution, middleware, transport infrastructure and customer premise equipment.
The content distribution module contains live encoding platforms, video file repository and IPTV video servers which are the key elements enabling video feeds for an IPTV service.
In general, content distribution (in the headenddisambiguation ), processing and adaptation are all part of the functions of a TV headend.
While the live video encoder and IPTV video server are conceptually considered to be part of the TV headend, they not necessarily need to be placed at the same physical location. Multicast video sources are usually located at the top level of the core network for better bandwidth efficiency, whereas unicast IPTV video sources are commonly installed at the local PoP level to minimize core bandwidth usage.
IMS architecture for IPTV
There is a growing standardization effort on the use of the 3GPP IP Multimedia Subsystem (IMS) as an architecture for supporting IPTV services in carriers networks. Both ITU-T and ETSI are working on so-called "IMS-based IPTV" standards (see e.g. ETSI TS 182 027). The benefits of this approach are obvious. Carriers will be able to offer both voice and IPTV services over the same core infrastructure and the implementation of services combining conventional TV services with telephony features (e.g. caller ID on the TV screen) will become straigthforward .