NVIDIA developer blog 'NVSwitch Accelerates NVIDIA DGX-2'

First-party source for the FIRST NVSwitch generation, which had no record in this repo, and the only NVIDIA page that states its port rate. Carries the Hot Chips 2018 figures: 'NVSwitch is a non-blocking NVLink crossbar with 18 ports at 51.5 GBps each, enabling any GPU pair to communicate at 300 GBps bidirectional bandwidth without interference' and '928 GBps aggregate bidirectional bandwidth'. The 18 x 51.5 = 927 ~ 928 identity confirms the port figure and shows the 300 GB/s is the bidirectional per-GPU rate, matching the V100's six NVLink 2 links. DGX-2 holds 16 V100 32 GB.