OpenSFF Compute Node Specification

2. Compute Node Overview

OpenSFF provides a basis for building fully-featured systems for desktops and servers. The standard defines physical dimensions, electrical interface requirements, airflow, and other aspects that ensures the best possible compatibility between nodes and enclosures following the OpenSFF specification.

In all cases, this standard aims to specify only the minimum required details necessary and not interfere with the manufacturer’s ability to innovate and differentiate. Specifically, the following implementation details SHALL NOT be part of an OpenSFF standard:

• Manufacturer or distributor of components used
• Layout of components on the OpenSFF-compatible PCB as long as they reside entirely within the maximum dimensions set forth in this document
• Number and arrangement of additional I/O capabilities on the node’s I/O shield

To help with flexibility and reduce cost, the OpenSFF standard defines two node variants: Core and Enterprise. Both variants are designed to be interoperable, however, server features will only be accessible if both the node and the enclosure adhere to the Enterprise variant of the standard.

2.1 Core Features

Compute nodes following the Core variant are designed to feature a single SFF-TA-1002 4C+ connector (hereafter referred to as the Core connector). The pin assignments are not compatible with other standards like OCP NIC 3.0 that use the same connector.

The following signals are included on the Core connector:

• Two Ethernet ports, 2.5Gb or faster, named F1 and B1
• One DP 1.4 port or newer
• Power Button
• Reset Button
• Two USB 2.0 ports
• One USB-C port (24-pin connector), supporting at least USB 3.0 speeds
• One USB 3.0 Type A port

Notes:

The USB 3.0 Type A signal pin configuration MAY be used for external connectivity for Core enclosures. Additional external connectivity MAY also be provided by manufacturers via the I/O shield.

2.2 Enterprise Features

Compute nodes following the Enterprise variant of this standard MUST implement the Core connector as set forth in Section 2.1 with the same minimum capabilities.

Additionally, an Enterprise connector (SFF-TA-1002 4C) is used for the following signals:

• Two Ethernet ports, 2.5Gb or faster, named F2 and B2
• One USB-C port (24-pin connector), supporting at least USB 3.0 speeds

Notes:

The USB 3.0 Type-A signal referenced in Section 2.1 MUST be routed to an Ethernet-over-USB interface, which connects to the management module through an internal switch. This enables communication between the compute nodes and the management module.

Similar to Core nodes, manufacturers MAY optionally provide additional external connectivity for Enterprise variants through the I/O shield.