Issue No. 09 - September (1998 vol. 9)
DOI Bookmark: http://doi.ieeecomputersociety.org/10.1109/71.722222
<p><b>Abstract</b>—Three-dimensional packaging technologies are critical for enabling ultra-compact, massively parallel processors (MPPs) for embedded applications. Through-wafer optical interconnect has been proposed as a useful technology for building ultra-compact MPPs since it provides a simplified mechanism for interconnecting stacked multichip substrates. This paper presents the offset cube, a new network topology designed to exploit the packaging benefits of through-wafer optical interconnect in ultra-compact MPP systems. We validate the offset cube's topological efficiency by developing deadlock-free adaptive routing protocols with modest virtual channel requirements (only two virtual channels per link needed for full adaptivity). A preliminary analysis of router complexity suggests these protocols can be efficiently implemented in hardware. We also present a 3D mesh embedding for the offset cube. Network simulations show the offset cube performs comparably to a bidirectional 3D mesh of equal size under uniform, hot-spot, and trace-driven traffic loads. While the offset cube is not proposed as a general replacement for the mesh topology, it leverages the benefits of through-wafer optical interconnect more effectively than a mesh by completely eliminating chip-to-chip wires for data signals. Hence, the offset cube is an effective topology for interconnecting ultra-compact MCM-level MPP systems.</p>
MPP networks, ultra-compact systems, offset cube, 3D mesh, adaptive routing, deadlock freedom, 3D packaging, optical interconnect, through-wafer signaling.
J. L. Cruz-Rivera, D. Scott Wills and W. Stephen Lacy, "The Offset Cube: A Three-Dimensional Multicomputer Network Topology Using Through-Wafer Optics," in IEEE Transactions on Parallel & Distributed Systems, vol. 9, no. , pp. 893-908, 1998.