MRC (Multipath Reliable Connection) publicly released as an open OCP specification by OpenAI with AMD, Broadcom, Intel, Microsoft, and NVIDIA — a minimal RoCEv2 extension (Write/WriteImm only) with per-packet entropy-value spraying and SACK-based selective retransmission on lossy (PFC-off) Ethernet; packet trimming optional for fast NACKs; SRv6 source routing optional
May 2026observed
| Value kind | observed — Reported measurements, counts, and specifications keep the precision and scope stated by their source; an exact specification is not treated as a range. |
|---|---|
| Caveat | The OCP spec document (Release 1.0) is dated March 21, 2026; OpenAI's public release was May 5, 2026, with partner announcements May 6. Production use is consortium-reported: the companion paper (arXiv:2605.04333) documents MRC in production at OpenAI and Microsoft, including a 50k-GPU OpenAI production pretraining job and a 75k-GPU pretraining job (organization unattributed). |
| As of | 2026-05 |
| Source | Open Compute Project |
| Review | checking…review by 2026-09-25 · standard cadence |
| Recorded changes | last 2026-08-24 · 2 revisions tracked |
| Claim id | mrc-open-transport-spec-released |
Where the guide uses it
← Full numbers register — every date-stamped figure in the guide, with revision history.