This book addresses two aspects of network operation quality; namely, resource management and fault management.
Network operation quality is among the functions to be fulfilled in order to offer quality of service, QoS, to the end user. It is characterized by four parameters:
– packet loss;
– jitter, or the variation of delay over time;
Resource management employs mechanisms that enable the first three parameters to be guaranteed or optimized. Fault management aims to ensure continuity of service.
Internet Protocol (IP), Multiprotocol Label Switching (MPLS) and Ethernet are the main technologies deployed by operators, in the case of wide area networks (WANs), and by businesses, in the case of local area networks (LANs). Initially, these technologies were not designed to deal with resource management, which partly explains their simplicity and commercial success. The features offered were sufficient at the time to offer services without QoS (best effort) constraints, such as web access and electronic messaging.
Resource management is indispensable when QoS constraints need to be taken into account. Voice and video are two applications illustrative of strong QoS requirements. Resource management can be provided using two different approaches:
– resources are managed node by node. No resource is allocated to a flow from end to end. In this case, there is a risk of congestion, as the resources of one node may become insufficient to meet demand. The ...