A presently used data network (network) includes numerous networking components and data communication paths (links) there-between. To reach from one point in the network to another, such as from one application on one data processing system to a service provided by another data processing system, data, such as in the form of packets, has to traverse several networking components and links.
Quality of service provided by a network or a portion thereof depends on several factors. For example, the quality of service between two points in a given network can degrade below a threshold indicator of quality due to a failure in a networking component or a link. As another example, the quality of service between two points in one portion of a given network can degrade below a threshold indicator of quality because a networking component or a link has failed in another portion of the network and the data traffic from that other portion is flowing through the first portion causing congestion and other performance degrading problems.
A networking component sending out of order packets, e.g., in a route flapping scenario, can also lead to below threshold quality of service in a network. External events, such as bust of network traffic due to unusual demand for a service, or maintenance or shutdown in a part of the network, can also lead to quality of service issues. Poor capacity planning in the design of the network can cause quality of service degradation under the right circumstances.