Reliability issues in network planning

Summary form only given. Capacity, reliability, and delay are three "magic words" used for describing concepts of computer network design. While capacity and delay are relatively well understood, this is not the case for reliability. The term reliability is often used interchangeably with availability and dependability. Increased redundancy in the network structure is often considered as an important, or even the only, way to achieve higher levels of reliability. The tutorial presents the role of reliability (in a broad sense) in network design. Factors affecting performability of the communications system are discussed. Reliability in the network design process, in the context of a systems approach to network design, is considered in more detail. Examples of calculations of reliability figures for different network designs are considered using the Delite tool. Reliability support in communications protocols is discussed. Examples of simulations and animations of network dynamics are presented using the ns-2 and nam tools