Border Gateway Protocol (BGP) is the de facto standard for inter-domain routing. BGP faces challenges such as increases in routing table size proportional to increases in the number of networks, high convergence times, and high churn rates, among others. Modularity in routing can address several of these challenges. In this article, we discuss a modular routing architecture, its application to the current Internet, and evaluate its scalability in terms of churn rate and routing table size. Optimization opportunities offered by the modular routing architecture are discussed. Briefly, a transition approach to deploy such an architecture, through a Layer 2.5 protocol, is also presented.