OEM Ethernet Switch Modules: Board-Level Switching for Integration

An OEM Ethernet switch is a managed switch that an equipment maker builds into its own product rather than installing as a separate box, usually as a board-level switch module or switch board mounted inside the host system. The switching silicon and management software are the same as in a boxed switch; the enclosure, connectors and power become part of the product it goes into.

Most network switches are boxes: a sealed enclosure with ports on the front. An embedded, or board-level, Ethernet switch is the switch without the box, the same managed switching silicon on a module or board that mounts inside your system. For an embedded or rugged design where space, weight and integration matter, that distinction is the difference between bolting a separate switch and its cabling onto the platform and building the switching into it.

This guide is for the engineers designing that product. It explains the difference between a switch module, a switch board, a boxed switch and a custom design, what a carrier board has to provide, which managed features to specify, and how OEM and ODM routes differ. It ends with examples from the Diamond Systems range, a checklist and answers to common questions.

Board-level switching comes in two packages, and both sit alongside the boxed switch and the fully custom design. The right one depends on how much hardware you want to design and how the switch will be packaged.

The categories follow the same split: Ethernet switch modules for carrier designs, Ethernet switch boards for standalone use, and rugged boxed switches built from the same switching core.

A board-level switch module is a fully functional managed switch built as a board rather than an appliance, typically a small board-level module or a board on a standard embedded footprint such as PC/104. It carries the switch chip, the management firmware and processor, and either the physical-layer interfaces or the signals to them, and it is designed to be integrated onto a carrier or stacked into a host system. It does everything a boxed managed switch does, including VLANs, QoS, redundancy, Layer 2+ switching and Layer 3 routing; it simply leaves the enclosure, connectors and power to the system it goes into.

Diamond Systems uses precise names for the two packages. An EPSM part is an Ethernet switch module that plugs into a carrier through high-speed board-to-board connectors; an EPS part is an Ethernet switch board that runs on its own. Several EPS boards are built on EPSM modules, so a design can start on the board and move to a custom carrier later with the same switching core and software.

The reason is integration. Building switching in at board level removes a separate enclosure, its mounting and the cabling between boxes, which saves size, weight and points of failure: the SWaP-C argument that drives most embedded and vehicle designs. It also lets the port layout, connectors and power match the host system exactly, rather than adapting to an off-the-shelf box. And because the module is a proven building block, a custom switch configuration can be created quickly and at low risk by integrating it onto a carrier board, instead of designing switch silicon from scratch.

With a switch board, the integration work is mounting and cables. With a switch module, the carrier board you design becomes part of the switch, and the items below are yours to get right. Diamond Systems supports this with carrier design guides, development kits with carrier design files, and a custom carrier board service where a project needs one.

Our FAQs on custom carrier boards, SFP and conformal coating cover the background. The same approach is common in embedded computing, where a processor module sits on a carrier that the product designer controls.

Board-level switches come in software levels as well as port counts. Diamond’s builds are Layer 2, Layer 2+ or Layer 3, some with IEEE 1588 PTP and some with Time-Sensitive Networking. The software level is chosen at order time, so it belongs on the specification.

Our FAQs on managed switches, link aggregation and port mirroring explain the features, and our TSN guide covers deterministic networking. One feature the Diamond range does not offer is PoE: if the product must power cameras or sensors, the PoE has to come from elsewhere in the design.

Equipment makers sometimes ask whether to integrate a standard switch module (the OEM route) or have a switch designed for them (the ODM route). Our FAQ on OEM vs ODM explains the terms; for switches, the practical differences are below.

Between the two sits the semi-custom route: a standard module on a carrier the switch maker designs for you. Diamond offers that as a custom carrier board service, which keeps the proven core while you get your own port layout and connectors without designing the board yourself.

If the switch sits in a rack or a cabinet, a boxed switch is the simpler package: it is easy to deploy, service and replace, and there is no integration work. Board-level suits a switch that lives inside a constrained system, such as a vehicle, a sealed chassis or an airborne or man-portable platform, where every cubic centimetre and gram counts and a separate enclosure adds weight and cabling. Because the board-level module and the rugged boxed switch can share the same switching core, the choice is about packaging, not capability: you can integrate the module now and move to a boxed build later, or the reverse, without changing the network design.

Defence platforms add their own requirements for power, EMC and connectors. Our guide to how a military Ethernet switch is built follows a board-level core into a sealed MIL-STD switch, and our guide to the types of Ethernet switches compares board-level designs with DIN-rail, rack and M12 switches.

Diamond Systems builds the modules and boards below; we supply them and help you choose the right one for your design. Figures are from Diamond’s published information in our catalogue.

All are rated for −40 to 85 °C with the specified cooling. The PC/104 boards stack with the computers and I/O in our guide to PC/104, and the full families are in our embedded Ethernet switches range; for cabinet and DIN-rail networks, see our industrial Ethernet switches.