In this paper we present an analytical model for estimating architecture-based software reliability, according to the reliability of each component, the operational profile, and the architecture of software. Our approach is based on Markov chain properties and architecture view to state view transformations to perform reliability analysis on heterogeneous software architectures. We demonstrate how this analytical model can be utilized to estimate the reliability of a heterogeneous architecture consisting of batch-sequential/pipeline, call-and-return, parallel/pipe filters, and fault tolerance styles. In addition, we conduct an experiment on a system embedded with three architectural styles to validate this heterogeneous software reliability model.