The basic points that should be fulfilled by the network service in order to provide QoS for video communications are examined in the following paragraphs. These include the throughput, delay and error characteristics of the network service. Extending the scope of QoS to the advanced functionality of the service, multicasting capability is also examined.
It has to be stressed here that the concept of QoS is applying to end-to-end connections, in the particular case multimedia connections. Video is just one of their components, however, it is the most demanding in terms of network service and it has the greatest impact on the overall QoS.