E1 services availability in EMS SDH network

In the paper is given availability analysis of telecommunication network build on synchronous digital hierarchy (SDH) and optical ground wires (OPGW). We have examined three special cases which characterize network availability, with real values of failure rates. It is given availability dependence on repair times for multiplexer and cable and basis on previous operating experience, review of existing status and suggestions for improvement. We have reconsidered the classical E1 service. Charts of the modeled paths are given at the end.