Protocol analysis involves several parameters in model specification, for instance, transmission delay or the length of the transmitting window. Verification of the model with parameters is a semi-decision process that depends on the number of clocks, parameters and counters in the model. Using combination of different verification tools for timed models as HyTech, TReX and UPPaal we are able to find relation between parameters satisfying desired property. The paper gives a report on the synthesis of parameters of PGM protocol. We built a formal model based on extended time automata with parameters and verified the reliability property. Our results automatically obtained from the model are consistent with previous results derived manually. The paper describes our experience with parametric verification of multicast protocol PGM. Results mentioned in the work were made with collaboration with Mihaela Sighireanu (Mihaela.Sighireanu@liafa.jussieu.fr) from LIAFA, Paris.