## Appendix E Quality of the switching system, QoSS,  
\[QoS_{SS}=\left(\frac{SuccCalls_{Peak}\cdot F_{Calls}}{AllIntCalls_{Peak}}+\frac{Succ RTVid_{Peak}\cdot F_{RTVid_{Peak}}}{AllRTVid_{Peak}}\right)\cdot 0.1\]  
where:  
* QoSSS--The quality of the switching system,
* SuccCalls\({}_{\text{Peak}}\)--Successfully established and maintained calls (until the end of the duration) during peak load times,
* AllInCalls\({}_{\text{Peak}}\)--All initiated calls during peak load times,
* F\({}_{\text{Calls}}\)--A factor that describes the importance of calls in the operator's overall business,
* SuccRTVid\({}_{\text{Peak}}\)--Successfully established and maintained (to completion) video calls and live video streaming during peak load times,
* AllRTVid\({}_{\text{Peak}}\)--All video calls and live video streaming of events at peak times,
* F\({}_{\text{Video}}\)--A factor that describes the importance of direct video calls and direct video transmission for the telecom operator's business. **Quality of the billing system, QoSS,**  
\[QoS_{BS}=\left(\frac{RefT_{TM}\cdot F_{TM}}{MaxT_{TM}}+\frac{RefT_{GTM}\cdot F _{GTM}}{MaxT_{GTM}}+\frac{RefT_{ET}\cdot F_{ET}}{MaxT_{ET}}\right)\cdot 0.1\]  
where:  
* QoSB--The Quality of the billing system,
* RefTTM--Reference (optimal) time for commercialization of new tariff models--from obtaining details from Product Development to commercialization for end users,
* MaxTTM--The maximum time it took to create a specific tariff model on the billing system of the analyzed telecom operator,
* FTM--A factor that defines the importance of the time of creation and commercialization of tariff models on the billing system,
* RefTGT--Reference (optimal) time for commercialization of new groups of tariff models and tariff groups--from obtaining details from Product Development to commercialization for end users,
* MaxTGT--The maximum time it took to create a specific group of tariff models or tariff groups on the billing system of the analyzed telecom operator,
* FTM--A factor that defines the importance of the time of creation and commercialization of a group of tariff models and tariff groups on the billing system,
* RefTET--Reference (optimal) time for redefining (supplementing or changing) existing tariff models, groups of tariff models or tariff groups--from obtaining details from Product Development to the end of the process and commercialization,
* MaxTEM--Maximum time for redefining (supplementing or changing) existing tariff models, groups of tariff models or tariff groups--from obtaining details from Product Development to the end of the process and commercialization,
* MaxTEM--A factor that defines the importance of time for redefining (supplementing or changing) existing tariff models, groups of tariff models or tariff groups. **Quality of obtaining reports from databases, QoDWh,**  
\[QoS_{DWh}=\left(\frac{RefT_{PDR}\cdot F_{PDR}}{MaxT_{PDR}}+\frac{RefT_{AHR} \cdot F_{AHR}}{MaxT_{AHR}}\right)\cdot 0.1\]  
where:  
* QoDWh--Quality of obtaining reports from databases,
* PDR--Pre-Defined Reports,
* AHR--Ad Hoc Reports,* RefT\({}_{\text{PDR}}\)--Reference set time for execution of predefined reports,
* MaxT\({}_{\text{PDR}}\)--Maximum time for running predefined reports,
* F\({}_{\text{PDR}}\)--A factor that indicates the importance of predefined reports for the regular business of the company,
* RefT\({}_{\text{AHH}}\)--Reference set time for execution of ad hoc reports,
* MaxT\({}_{\text{PDR}}\)--Maximum time for running ad hoc reports,
* F\({}_{\text{PDR}}\)--A factor that indicates the importance of pad hoc reports for the regular business of the company,
* F\({}_{\text{PDR}}\) + F\({}_{\text{AHH}}\) = 1.