ANALYSIS OF METHODS ENSURING PON AND LR-PON NETWORK RELIABILITY INDICATORS. PART I
PURPOSE. The paper deals with the circuits ensuring PON reliability indicators presented in ITU-T Recommendations G.983.1, G.983.5, G.989.1 and updated circuits of ITU-T G.983.1 recommendations. Analysis is given to the following economical circuits ensuring reliability indicators: “neighboring protection”, a single ring, a dual ring and hybrid topologies based on the use of “tree” and “ring” topologies. The presented protection circuits are compared. METHODS. Given the structure of each protection circuit, structural reliability diagrams are developed and unavailability factors are calculated. Calculations are performed using the mathematical program MathCAD. RESULTS AND THEIR DISCUSSION. The lowest unavailability factors are obtained for the networks using protection circuits of types C and D1, since these protection circuits provide for the duplication of all network elements. If PON without protection is not taken into account, the highest unavailability factor is predicted for the networks using the type A protection circuit. This is due to the availability of backup of the backbone cable only. CONCLUSIONS. When using some or another protection circuit the operator can provide the required level of the reliability indicator PON and LR-PON. However, when designing and deploying a network the future operating costs should be evaluated in addition to capital costs.