  NaNet is an FPGA-based PCIe X8 Gen2 NIC supporting 1/10 GbE links and the
custom 34 Gbps APElink channel. The design has GPUDirect RDMA capabilities and
features a network stack protocol offloading module, making it suitable for
building low-latency, real-time GPU-based computing systems. We provide a
detailed description of the NaNet hardware modular architecture. Benchmarks for
latency and bandwidth for GbE and APElink channels are presented, followed by a
performance analysis on the case study of the GPU-based low level trigger for
the RICH detector in the NA62 CERN experiment, using either the NaNet GbE and
APElink channels. Finally, we give an outline of project future activities.
