Quality of Service
Since different applications — for example, telephone, e-mail and surveillance video — may be using the same IP network, there is a need to control how network resources are shared to fulfill the requirements of each service. One solution is to let network routers and switches operate differently on different kinds of services (voice, data, and video) as traffic passes through the network. By using Quality of Service (QoS), different network applications can co-exist on the same network without consuming each other’s bandwidth.
The term, Quality of Service, refers to a number of technologies such as Differentiated Service Codepoint (DSCP), which can identify the type of data in a data packet and so divide the packets into traffic classes that can be prioritized for forwarding. The main benefits of a QoS-aware network include the ability to prioritize traffic to allow critical flows to be served before flows with lesser priority, and greater reliability in a network by controlling the amount of bandwidth an application may use and thus controlling bandwidth competition between applications. PTZ traffic, which is often regarded as critical and requires low latency, is a typical case where QoS can be used to guarantee fast responses to movement requests. The prerequisite for the use of QoS within a video network is that all switches, routers and network video products must support QoS.