Meta lays out 448G in-rack interconnect roadmap: PAM6 candidate, active copper cables stretch reach
StewartalsopIII · x · 2026-10-18
Meta's IEEE 802.3 working group presentation "Scaling the Rack: Electrical Interconnect for Hyperscaler Compute Demands" maps the path to 448G in-rack electrical interconnect: 400G rack prototypes (e.g. Vera Rubin NVL72) → 2027 PHY prototypes → 2028 full systems, with early spec settlement to keep systems multi-vendor. Key data: PAM6 is the strong candidate for 448G CPC channels (backplane 12dB/m IL @90GHz); CPC must be managed as a supply-chain and reliability program; active copper cables (ACC/AEC) extend reach from 0.6m to 1.4–3.7m at +25% to +137% power cost. The sharer also notes these dense-but-ugly slides are the first AI-generated ones he's seen.
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