Crossbar based design schemes for switch boxes and programmable interconnection networks

Crossbars have been considered one of the most standard switching modules in conventional communication networks due to its simplicity in routing algorithm and fabrication regularity. While in programmable on-chip interconnection networks such as the routing networks in field programmable gate arrays (FPGAs), switch boxes are often used for a better tradeoff between routability and area efficiency. Much work has been done on the topology design of switch boxes, e.g. universal switch boxes and hyper-universal switch boxes. However, the layout design of switch boxes tends to be difficult when the topology of switch boxes is less regular. In this paper we revisit the theoretical design aspects of the classic crossbar design schemes and further investigate a new design style, a so called meta-crossbar, which is obtained from a crossbar by adding the least number of switches and direct contacts to achieve the desired optimal routability. We show that a switch box can always be implemented by a meta-crossbar. This means that the layout design of switch boxes can be done almost like crossbars. As a result, we present a hyper-universal meta-crossbar design, and a three level meta-crossbar based interconnection network design, which is capable of routing all group communication requirements.