We present a de-layered protocol engine for termination of 40Gbps TCP connections using a reconfigurable FPGA silicon platform. This protocol engine is designed for a planned attempt at the internet speed record. In laboratory demonstrations at 40Gbps, this core beat the previous record of 7.2Gbps by a factor of five. We present an aggressive cross-layer optimization methodology and corresponding design-flow and tools used to implement this record-breaking TCP protocol engine. The 40Gbps TCP Offload Engine has been implemented on a Xilinx FPGA platform, based on a VirtexII-pro 2VP7 device. Each FPGA device terminates a 10Gbps OC-768 channel, and the aggregate capacity of the four FPGA devices is 40Gbps. The four 10Gbps channels are intended to be connected to four trunked 10GbE Ethernet ports on a router. The 40Gbps TCP implementation has been demonstrated in the lab in system level as well as gate-level simulations, and live implementations have been tested with each 10Gbps channel FPGA board connected back-to-back in transmission tests at full wire-speed. We believe this to be the fastest TCP protocol engine to have been implemented so far

Static redundancy allocation is inappropriate in hard real-time systems that operate in variable and dynamic environments, (e.g., radar tracking, avionics). Adaptive fault tolerance (AFT) can assure adequate reliability of critical modules, under temporal and resource constraints, by allocating just as much redundancy to less critical modules as can be afforded thus gracefully reducing their resource requirement. We propose a mechanism for supporting adaptive fault tolerance in a real-time system. Adaptation is achieved by choosing a suitable redundancy strategy for a dynamically arriving computation to assure required reliability and to maximize the potential for fault tolerance while ensuring that deadlines are met. The proposed approach is evaluated using a real-life workload simulating radar tracking software in AWACS early warning aircraft. The results demonstrate that our technique outperforms static fault tolerance strategies in terms of tasks meeting their timing constraints. Further, we show that the gain in this timing-centric performance metric does not reduce the fault tolerance of the executing task below a predefined minimum level. Overall, the evaluation indicates that the proposed ideas result in a system that dynamically provides QoS guarantees along the fault-tolerance dimension.