Service Level Agreement with Differentiated Reliability Requirements : Efficiency of Application in Communication Networks and On-Board Systems

The reliability of the operation of fiber-optic networks and communication systems, i.e. the ability of a communication network to perform specified functions for transmitting information under specified conditions and for a specified time is the main requirement of customers for a telecommunications operator. The customer’s needs and expectations regarding the quality and reliability of the network and communication systems determine the requirements. They may differ not only qualitatively and quantitatively, but also depend on time. Customers of telecommunications companies may need certain periods of time during which additional stability of communication is required. The rest of the time, the standard level of communication stability is sufficient for them. The overall framework of the SLA usually provides increased reliability for the entire duration of the contract concluded between the customer and the operator, which is sometimes redundant and expensive for both the customer and the operator. The SLA framework is considered, which allows customers to independently determine the critical time slots in which the operator undertakes to fulfill their requirements for communication stability. This structure is called the SLA with differentiated requirements (SLAd). Critical Time Slots (CTS) correspond to periods when it is especially important for the customer to have reliable and uninterrupted communication. Therefore, connections during these periods are reserved using cross-duplication of customer data streams. The article evaluates the effectiveness of the implementation of a service level agreement (SLA) with time-differentiated reliability requirements. Net present value (NPV) is considered as a measure of efficiency; to take into account the probabilistic characteristics, the availability factor is applied. The results of calculations are presented and their brief analysis is given.