A method for constructing a network topology is applied in a streaming delivery system. The data terminal receives a summary of service data from a data provider apparatus over the Internet, and if desired, demands the data provider apparatus to provide the service data over the Internet. Based on the expected proportion of a plurality cells which will be nonempty in a random distribution, a Poisson distribution or a Binomial distribution is utilized to determine a data sample mean. The strength member exhibits low smoke generation and low flammability properties.