Global routing revisited.

Recent progress in the area of global routing has been remarkable; yet, in many ways, the classical formulation has yet to catch up with the demands imposed by modern physical synthesis flows. In this work, we visit (and revisit) the topic of global routing. We provide a brief review of global routing's history, and touch on recent work that has contributed to the state-of-the-art in the field. While we cover in depth the basic principles behind leading approaches, we also emphasize open challenges and problems that remain unresolved. We argue that not only does the current academic formulation lack key components of the true routing problem - such as scenic control, layer directives, and capabilities for integration with physical synthesis - but also that present methods are likely to fail when extended toward the more generalized formulation. Finally, we offer a revised incarnation of the ISPD benchmarks to encourage continued progress in the research community.