Accurate Cable Length Measurement for Optimized Data Center Networking#

Speakers: Jasmeet Bagga (Facebook), Mehak Mahajan (Broadcom)

• Why: Cabling is a named core interest, and this pairs a Meta production deployment (operational benefits, real use cases) with a Broadcom technical deep dive including the SAI attributes that make it deployable — an unusually complete story for a plumbing topic.
• What: Inferring physical cable length via silicon-driven link delay measurement, with Meta presenting real-world deployment experience and observed operational benefits, and Broadcom detailing the delay-measurement methodology and the SAI attributes/APIs that support it. (from abstract only)
• How: High-precision link delay measurement from switch silicon, exposed through SAI, used both for accurate cable-length inventory and for performance monitoring.
• Where applicable: Broadcom silicon with the SAI delay-measurement attributes (silicon-dependent), deployed at Meta — the use cases (cable inventory accuracy, layout validation, latency anomaly detection) apply to any large DC.