The use of formal description techniques allows the partial automation of the design, the validation, and the implementation of communication protocols and distributed algorithms. In this paper, we present a methodology for validation of distributed algorithms and protocols, and our experiences of using the Estelle language, and a simulation and validation tool, called Veda, to simulate and validate complex distributed algorithms for the distributed implementation of multi-rendezvous. Some design errors in published distributed rendezvous algorithms were found. We obtain from these experiences heuristic guidelines for trouble shooting of distributed algorithms.