Search for extraterrestrial intelligence (SETI) is indeed a great challenge to astronomers since its method of communication, direction of propagation as well as spectral pattern are all unknown earlier. Due to all of these various restrictions, the problems have become complex and thus the science has become a 'hard science'. As galactic societies would be transitory, an obvious solution is an interstellar communication network, or type of library mostly consisting of automated systems to store the cumulative knowledge of vanished civilizations and thereby to communicate the knowledge...