Credo and Oracle said on November 4, 2026, that the Open Compute Project (OCP) Community had approved two optical-transceiver specifications. One sets out how compliant modules report link telemetry and health; the other defines a way for transceivers at opposite ends of a link to exchange management messages over that link. Credo and Oracle’s announcement describes the approval, and OCP’s Optics Reliability Workstream page lists both documents as contributions.
Two specifications, two different jobs
The Enhanced Telemetry Optics Product Software Specification defines a software framework for collecting and accessing transceiver diagnostics. The Transparent Remote Optical Transceiver Messaging with ePPS Design Specification describes the message channel between digital signal processors (DSPs) at the two ends of a link. The first covers telemetry; the second provides a transport for remote messages.
| OCP specification | What it defines | Supported transceiver rates |
| Enhanced Telemetry Optics Product Software Specification | Telemetry collection, link-health scoring, event logging and configurable responses | 400G, 800G and 1.6T |
| Transparent Remote Optical Transceiver Messaging with ePPS Design Specification | In-band messaging between transceiver DSPs, plus ePPS synchronization and link-latency calibration | 400G, 800G, 1.6T and 3.2T |
Both documents are intended to apply independently of the module’s physical-medium-dependent (PMD) type. Their revision histories date the documents to October 8, 2026. The telemetry specification and messaging design specification describe requirements and interfaces for compliant transceivers.
What the link-health rating measures
The telemetry specification covers signal and error conditions on both the host and optical-media sides. Its metrics include signal-to-noise ratio (SNR), eye height and PAM4 level-transition parameters, optical multipath interference, pre-FEC bit-error rate, forward-error-correction (FEC) statistics, uncorrectable codewords, relinks, loss-of-signal and loss-of-link events, uptime, temperatures and diagnostic flags. The refresh interval is configurable from 1 to 10 seconds.
For its link-health rating, the specification assigns category scores of 80, 60 or 40 and uses the lowest category score, rather than averaging categories. A weak reading therefore cannot be offset in the rating by stronger readings elsewhere. Host-side and media-side scoring categories differ, while link-down and FEC counters are excluded from the rating by default. Thresholds for several measurements, including SNR, eye height, pre-FEC BER and FEC bins, can be configured.
The document also specifies non-volatile event logs, so entries can persist through module removal and reinsertion. Each entry is 32 bytes and includes a UTC timestamp with nanosecond precision, an event ID and detail fields. A programmable hysteresis interval suppresses duplicate event entries; its default is 10 seconds. Automatic shutdown is optional and disabled by default. When enabled, the module can enter a fault state when the link is unhealthy and record that event.
How remote messages use the existing link
The ePPS design carries management traffic in-band, within the existing link, rather than over a separate optical channel. A slightly higher line-side SerDes clock creates room to insert a 256-bit management slot after a programmable number of 256-bit data blocks. The recommended interval is one slot per 30,000 data blocks.
A message uses five 240-bit payload blocks, for 1,200 payload bits; 16 bits in each slot are vendor-defined. The specification describes bandwidth of about 3 Mbit/s. It also describes packet numbering, CRC checks and firmware acknowledgements or negative acknowledgements to handle message integrity. The design does not require a separate messaging fiber, laser or receiver, and it includes enhanced pulse-per-second (ePPS) synchronization and round-trip link-latency calibration.
The software specification draws a practical compatibility boundary: a compliant module must be able to establish a link with third-party optics, but those optics do not provide the enhanced telemetry features. Access to the specified telemetry therefore depends on compatible features at the relevant endpoints. James Kelly, vice president of Market Intelligence and Innovation at the OCP Foundation, said the specifications’ impact would depend on ecosystem adoption in the announcement.
The documents define how telemetry, scoring, logging and remote messaging are meant to work. Their operational benefits remain tied to whether compatible equipment and software adopt the specifications.
