Nvidia Reveals 51Tbps Ethernet Switch

Due to sample late this year, Spectrum-4 will quadruple the bandwidth of Spectrum-3 by both doubling per-lane speed to 100Gbps and doubling the number of serdes lanes to 512, yielding 51.2Tbps.

Bob Wheeler

About two years after completing the Mellanox acquisition, Nvidia announced Spectrum-4, its next-generation Ethernet-switch chip. The new chip will quadruple the bandwidth of Spectrum-3 by both doubling per-lane data rate to 100Gbps and doubling the number of serdes lanes to 512, yielding 51.2Tbps. Nvidia will build this 100-billion-transistor chip in the same TSMC 4nm process as its Hopper GPU, targeting air-cooled system designs. Samples are due late this year, followed by production in early 2023.

Spectrum-4 will handle 128x400G or 256x200G-and-below standard Ethernet ports, and it’ll also support 64x800G ports using the Ethernet Technology Consortium’s 800G specification, an industry ad hoc standard. Nvidia says its 112Gbps PAM4 serdes will drive copper (DAC) cabling within a rack, avoiding the added cost and power of active cables. The chip’s undisclosed number of packet-processing pipelines handle an aggregate 37.6 billion packets per second into and out of a fully shared packet buffer. One-quarter of its ports perform MACSec encryption, allowing protection for up to 12.8Tbps of tunneled traffic (using VXLAN). For out-of-band management and configuration, the chip includes two 25G Ethernet ports and a PCIe Gen4 x4 host interface.