Minimal overhead fault masking scheme for broadband multi-channel switching

We propose a switching module architecture called the multicasting multi-channel crossbar (MMCC), which was implemented in the MASCON IC. Using this switch module, we investigate the fault tolerance of multistage interconnected networks (MINs), which is a critical matter in public broadband switches. Specifically, we investigate the fault tolerance of MINs constructed from switch modules with multi-channel capability (such as the MMCC). We demonstrate the inherent fault tolerance of internal stages of multi-path (e.g. Clos) MINs constructed from MMCC modules, which alone asserts the benefits of such MINs over the MINs based on single-channel modules. Specifically, through the reconfiguration of the multi-channel groups, cells destined for faulty output channels or channels connected to faulty modules can be redirected, either though a hard partition or multichannel statistical multiplexing to other output channels. Finally, we specify an overall fault masking mechanism which can mask one or more faults in each stage of a MIN, with 1/G pin count overhead and 1/G overhead in the number of spare modules added (where G is the number of channel groups for the switch modules). This approach eliminates the need for additional fabric components such as multiplexers and also requires a minimum amount of logic and pin overhead for fault masking.