Software reliability techniques are aimed at reducing or eliminat-ing failures in software systems. Reliability in software systems istypically measured during or after system implementation. How-ever, software engineering methodology lays stress on doing the"correct things" early on in the software development lifecycle inorder to curb development and maintenance costs. In this paper, wepropose a framework for reliability estimation of software compo-nents at the level of software architecture.

Software reliability techniques are aimed at reducing or eliminating failures in software systems. Reliability in software systems has traditionally been measured during or after system implementation. However, software engineering methodology lays stress on doing the "correct things" early on in the software development lifecycle in order to curb development and maintenance costs. In this paper, we argue that reliability of a software system should be assessed throughout the system's life span, starting with the software architecture level. Our research goal is to estimate the reliability of software systems in early design stages, which we believe involves the ability to reason about numerous uncertainties that exist in this stage, including uncertainty due to lack of execution artifacts. Our proposed approach is to develop techniques that will couple software architectural models with a suite of stochastic reliability estimation models and allow us to reason about these uncertainties. In this paper, we present our recent results using our technique for reliability estimation of software components at the level of software architecture. Another important part of this paper is the discussion of our ongoing research efforts and open research problems in this area.