From DSTV site:
Why do I have to be an Accredited ISP subscriber to gain access to DStv ON DEMAND via the Internet?
In the field of computer networking and other packet-switched telecommunication networks, the traffic engineering term quality of service (QoS) refers to resource reservation control mechanisms rather than the achieved service quality. Quality of service is the ability to provide different priority to different applications, users, or data flows, or to guarantee a certain level of performance to a data flow. For example, a required bit rate, delay, jitter, packet dropping probability and/or bit error rate may be guaranteed.
Quality of service guarantees are important if the network capacity is insufficient, especially for real-time streaming multimedia applications such as voice over IP, online games and Video On Demand, since these often require fixed bit rate and are delay sensitive, and in networks where the capacity is a limited resource, for example in cellular data communication.
A network or protocol that supports QoS may agree on a traffic contract with the application software and reserve capacity in the network nodes, for example during a session establishment phase. During the session it may monitor the achieved level of performance, for example the data rate and delay, and dynamically control scheduling priorities in the network nodes. It may release the reserved capacity during a tear down phase.
A best-effort network or service does not support quality of service.
DStv is committed to delivering the highest possible quality of service to our subscribers. As a result, we request certain guarantees from our ISP partners –
Our aim is to offer the service to as many broadband subscribers as possible. DStv has engaged with a number of ISP’s to offer DStv ON DEMAND online to our subscribers who have internet accounts with them. We are excited to partner with the selected ISP’s who have met our quality of service and technical requirements.
