In the fields of broadcasting and content delivery, (OTT) stands for over-the-top and is also referred to as "value added". Most of us have been using OTT services without actually realizing. Simply put, OTT refers to the service you use over the network services of your service provider with broadband delivery of video and audio without a multiple system operator being involved in the control or distribution of the content itself. The provider may be aware of the contents of the IP packets but is not responsible for, nor able to control, the viewing abilities, copyrights, and/or other redistribution of the content. IPTV and OTT (Over the Top) IPTV are two faces of the same coin.

Here is an example to better understand the concept. You have a 3G 4G data plan with a mobile operator, from which you have bought a smartphone and with which you have GSM calls and SMS service. Then, you use Skype or any other VoIP service i.e Whatsapp to make cheaper and free voice calls and SMS using the 3G / 4G / BWA network. Skype and WhatsApp here are referred to as the OTT service.

This is in contrast to purchase or rental of video or audio content from an Internet provider, such as Cable Television, DTH, or an IPTV service providers, like Home Digital, TATA Sky, AirTel. OTT-IPTV in particular refers to content that arrives from a third party, such as Netflix, TV-Anywhere or MyTV App, and is delivered to an end user device, leaving the internet provider responsible only for transporting IP packets. Consumers can access OTT-IPTV content through internet-connected devices such as PCs, Laptops, Tablets, Smart Phones, Android Set-Top Boxes, Smart TVs and DLNA Gaming Consoles such as PlayStation 3 and Xbox 360.

Internet Protocol Television

OTT-IPTV has also been a vector in the proliferation of Internet Protocol Television, also known as IPTV, which is the legal distribution of videos and television content over the Internet. These video OTT services are obtained online, from Youtube or Amazon Prime for instance and from other sites where more sustained and constant streaming video content are offered. Department of Telecommunication "DOT" IPTV definition:- An IPTV (Internet Protocol Television) service (or technology) is the new convergence service (or technology) of the telecommunications and broadcasting through QoS controlled Broadband Convergence IP Network including wire and wireless for the managed, controlled and secured delivery of a considerable number of multimedia contents such as Video, Audio , data and applications processed by platform to a customer via Television, PDA Cellular, and Mobile TV terminal with STB module or similar device."