An overview of theoretical solutions for fault-tolerant routing in telecommunication networks

In this article, the existing solutions in the field of fault-tolerant routing have been analyzed, which allowed formulating a list of key requirements that prospective solutions should meet, as well as mathematical models and methods on which they are based. These include flow-based traffic nature, which is a distinctive feature of most multimedia services and a compulsory moment when implementing bandwidth protection schemes and other network Quality of Service indicators; optimization problem statement: the focus on optimizing the use of available network resources; high scalability of solutions for fault-tolerant routing; support for basic protection schemes for network elements (node / communication link / path / bandwidth and QoS level for a set of indicators); coordinated solving of specific tasks for fault-tolerant routing, for example, default gateway protection, fast rerouting, etc .; extension of existing solutions to support load balancing associated with the implementation of a multipath routing strategy with appropriate support for protection schemes not single path, but a multipath, that is, the set of paths in which packets of the same flow are transmitted; acceptable computational complexity of routing solutions. The classification of perspective schemes of protection of the Quality of Service (QoS) level is developed, which is important to be implemented during the fault-tolerant routing of multimedia flows. Appropriate routing solutions should provide QoS protection at the same time for a variety of Network Performance (NP) or Quality of Experience (QoE) indicators, requiring the development of new or improved existing mathematical models and fault-tolerant routing methods in accordance with the requirements.