Parametric Analysis of PGM protocol - report

parametric verification, protocol, modelling, symbolic model-checking

The paper summarized the results of parametric analysis and verification of PGM protocol in ADVANCE project.

PGM protocol is a reliable multicast protocol running over unreliable network. Its main property is reliability - PGM guarantees that a receiver either receives all data packets and repairs, or it is able to detect unrecoverable data packet loss. However, it is interesting to know under which conditions the full reliability is obtained. Our work is focused on finding the constraints between parameters that satisfies full reliability property. We presents a new model based on a global view of PGM communication. Using verification tool TReX we synthetize parameters fully automatically. We discovered that standard data structures like PDBMs do not allowed to compute the number of definitively lost packets because of assignments for counters. For this reason, we need another data structure. We introduce a new data structure based on parametric intervals.