This chapter has briefly described the main network performance parameters which have a significant impact on customer satisfaction and, hence, in a competitive environment, market share. The increasing change to networks together with the introduction of new services makes performance engineering a complex task and it is necessary to issue detailed guidance to all concerned with the network and services it supports. The most severe degradation that customers can experience is loss of access to the network due to its failure, the greater the network outage the larger the impact on customers. The modern digital network is, in effect, a very large distributed processing system with multiple varieties of exchange processor with a multiplicity of software operating systems and service applications. The complexity of such a system is high and rising with the growth of services and network interconnect between operators. Although standards bodies specify interfaces, it is not possible to produce a detailed unambiguous specification. Hence, application of standards depends on the interpretation of equipment suppliers. Therefore, the risk of incompatibilities is high and the probability of software driven network outages is large. Furthermore, events of the past have shown that even minor errors in software design can cause major service-affecting network problems when unexpected combinations of circum stances or perturbations occur. There is also a long history of 'hacking' into computer networks and the malicious insertion of viruses that can cascade through computer systems rendering them inoperable; there is no reason to assume that telecommunications networks are immune from such attacks. It must be recognised that modern networks are fragile and that the design of networks and systems to maximise the preservation of network integrity is of paramount importance and will have an increasing influence on customer perceived QoS; particularly as networks become more complex and inter-networked services become more sophisticated.

Inspec keywords: quality management; telecommunication network management; telecommunication security; customer satisfaction; quality of service; telecommunication network reliability

Other keywords: QoS; computer systems; service-affecting network problems; software operating systems; internetworked services; quality of service management; telecommunications networks; distributed processing system; network outage; digital network; telecommunication management; network interconnect; network performance engineering; customer satisfaction; exchange processor; network failure; legacy networks; software design; computer networks

Subjects: Network management