OpenSFF Enclosure Specification

1. Introduction

This document defines the OpenSFF Enclosure Specification, which standardizes the electrical, mechanical, and functional characteristics of enclosures designed to host one or more OpenSFF Compute Nodes. It is intended primarily for enclosure manufacturers but also informs system integrators, developers, and partners building complete OpenSFF-based systems.

OpenSFF enclosures may take on a wide range of physical formats: from compact single-node Core enclosures resembling mini-PCs or integrated all-in-one systems, to larger tower or rack-mounted Enterprise enclosures supporting multi-node configurations.

Apart from minimum requirements due to the physical characteristics of compute nodes, this specification is otherwise agnostic to chassis dimensions and focuses instead on the common behaviors and requirements expected from compatible enclosures.

Two enclosure classes are defined:

• Enterprise Enclosures: Provide shared power distribution, built-in Ethernet switching, and KVM access. Enterprise Enclosures are required to have an OpenSFF Management Module (MM) slot for local or remote management options.
• Core Enclosures: Any other enclosure capable of supporting OpenSFF nodes but lacking some or all of the advanced, Enterprise Enclosure features.

This specification complements the OpenSFF Compute Node Specification (revision 25.-2) and the OpenSFF Management Module Specification. It defines the minimum mechanical and electrical infrastructure an enclosure must provide to be considered compatible with OpenSFF nodes, as well as class-specific requirements for Enterprise-grade capabilities.

Key concepts in this document include slot provisioning, KVM behavior, shared power design, and management fabric support.

1.1 Node and Enclosure Feature Compatibility

All OpenSFF compute nodes are mechanically compatible with both Core and Enterprise Enclosures. However, features such as additional interfaces, KVM, shared power, and management networks depend on both the node’s connectors and the enclosure’s infrastructure class.

Enterprise Enclosures MUST provide both the Core (4C+) and Enterprise (4C) connectors for each compute slot, enabling full signal compatibility with all node types. This ensures that any inserted Enterprise Node has access to its full interface set. Core Enclosures, by contrast, MAY omit the Enterprise (4C) connector entirely.

All Core Nodes will gain the following features when used in an Enterprise Enclosure:

• Shared Power Infrastructure
• Switched Networking for two networks
• KVM and remote management support

When using Enterprise Nodes in Core Enclosures, the following features present on the node may NOT be available:

• Two additional high-speed Ethernet ports
• One additional USB-C port supporting at least USB 3.0 speeds