network management software tool

Some network management software tool (such as marking and policing) can be applied in both the ingress and egress directions of the traffic flow on an interface. Other tools (such as queuing) can be applied only in the egress direction (with some platform-specific exceptions).

The QoS mechanisms (primarily DiffServ) described previously are applicable to packets already admitted to the network. Such tools are very effective in protecting real-time (voice) from non-real-time (data) traffic, but they are completely ineffective in protecting real-time applications from other real-time applications (that is, protecting voice traffic from other voice traffic). Such protection can be achieved only through call admission control (CAC) mechanisms, which decide whether to allow or disallow new packet streams onto the network. IntServ mechanisms, such as RSVP, can be used to implement discrete network management software tool