Broadcom Announces Tomahawk 6 - Davisson, the Industry's First 102.4-Tbps Ethernet Switch with Co-Packaged Optics
Per-bit optical power claim on a named part (BCM78919): 102.4 Tb/s optically enabled from 16 x 6.4 Tb/s engines at 200 Gb/s per link, 70% lower optical interconnect power — 'more than 3.5x lower than traditional pluggable solutions'. 512 XPUs scale-up, 100,000+ in two tiers. SAMPLING at announcement, not volume; 70% and 3.5x are the same claim stated twice.
Broadcom Tomahawk 6 – Davisson (BCM78919)
What it is
Broadcom's first co-packaged-optics variant of the Tomahawk 6 switch: the optics move onto the switch package instead of sitting in pluggable modules at the faceplate. The claim being made is not bandwidth — it is the power cost of moving that bandwidth.
The numbers, as published
| Item | Value |
|---|---|
| Part | BCM78919 |
| Switching capacity | 102.4 Tb/s, optically enabled (stated as an industry first) |
| Optical engines | 16 × 6.4 Tb/s "Davisson DR" engines |
| Per-link speed | 200 Gb/s per channel |
| Optical interconnect power reduction | 70% |
| Comparison to pluggables | "more than 3.5× lower" than traditional pluggable solutions |
| Scale-up | 512 XPUs in a single cluster |
| Scale-out | 100,000+ XPUs in a two-tier network at 200 Gb/s per link |
| Availability | Sampling to early-access customers and partners |
Why this number matters to the rung
networking's standing question is what does that bandwidth cost. Bandwidth-per-port figures answer nothing on their own; power per bit is the constraint that binds in a datacentre with a fixed feed, and it is the term that connects this rung to energy and datacenters.
Two readings the close read insists on:
- 70% and 3.5× are the same claim from two directions — a 70% reduction is roughly a 3.3× ratio. They are not two independent pieces of evidence, and a piece quoting both as if they were is inflating one number into two.
- The saving is scoped to "optical interconnect power", not to switch power or system power. The pluggable optics being displaced are a large but bounded share of a switch's draw. Nothing here says total platform power falls 70%.
Quotes (attributed)
- Near Margalit, VP & GM, Optical Systems Division, Broadcom — TH6-Davisson "represents significant advancement for AI infrastructure by enhancing link stability and energy efficiency."
- Andrew Qu, CEO, Micas Networks — "The timing of Tomahawk 6 – Davisson could not be better… delivers great power savings and rock-solid stability."
- Prasad Venugopal, VP HW Engineering, Nexthop AI — "This architecture delivers significant reduction in power consumption… at unmatched price/performance."
All three are vendor or partner voices. There is no third-party measurement in this document.
Limitations
- Vendor disclosure. Every figure is best-case and unaudited. Label them as such anywhere they are quoted.
- Dated 2025-10-08 and sampling at announcement. The proposal noted a later release claiming production volume — unverified, because the Broadcom product-release pages would not render on fetch. The 2026-08-27 sample-versus-volume discipline applies: sampling is not shipping, and this file records sampling.
- No power figure in watts, no per-port or per-bit absolute — only ratios against an unnamed "traditional pluggable" baseline. Without the baseline part, the ratio cannot be independently recomputed.
- Link-stability and reliability claims ("rock-solid") are qualitative.
Bears on
LITE (Lumentum) — the optics play bridging power and memory — and the re-homed photonic-interconnect thesis. The mechanism at issue for that position is whether CPO displaces pluggable transceiver volume or expands the optical content per system; this release is evidence for displacement at the switch face, which is the bear case for pluggable-module suppliers and the bull case for whoever supplies the optical engines and lasers.
Read against N3 (NVIDIA Spectrum-X Photonics), which makes a 3.5× power-efficiency claim on comparable framing — two vendors, same order of magnitude, is the only way a vendor number becomes usable.
Source: Broadcom Announces Tomahawk 6 – Davisson — Broadcom Inc., 8 October 2025.