How a Military Ethernet Switch Is Built

A military Ethernet switch is a managed network switch built to survive a military vehicle, aircraft or shelter and to meet the standards its programme is written against: MIL-STD-810 for environment, MIL-STD-461 for electromagnetic compatibility, MIL-STD-1275 or MIL-STD-704 for platform power, with sealed MIL-DTL-38999 circular connectors in place of RJ45 sockets. The switching inside is the same Ethernet as any managed switch; the build around it is what makes it military.

A military Ethernet switch is rarely something you buy off a shelf. The network has to survive the platform, with its shock, vibration, temperature extremes, dirty power and electromagnetic noise, while the port count, speeds and connectors have to match the system it goes into. These switches are built by integrating proven board-level switching into a rugged, MIL-rated system, rather than adapting a fixed product. Diamond Systems builds them around its own board-level switch modules; Things Embedded supplies them and helps you specify the right configuration for the platform.

This guide sets out what makes a switch military grade, standard by standard, then follows the build from switching core to power, enclosure and configuration. It covers connectors, the managed features defence networks rely on, the platforms that use them and the switches in our range, and ends with a specification checklist and answers to common questions.

No single standard makes a switch military. A programme calls up a set of standards, and the switch is designed and tested to meet the parts that apply. The table lists those met most often, with what each one means for a switch.

Our FAQs explain each one: MIL-STD-810H, MIL-STD-461, MIL-STD-1275, MIL-STD-704 and MIL-DTL-38999. Our overview of the US military standards that defence equipment is tested against puts them in context. One word of care: a manufacturer may say a switch is designed to, compliant with or tested to a standard, and the test reports behind that statement are what a programme asks for.

MIL-STD-810H is a set of test methods, not a pass mark. The programme chooses the methods and the levels from the platform’s life cycle profile, so two switches can both be tested to MIL-STD-810H and still have been tested to very different levels.

Moisture is the slow failure. A sealed case limits it, and conformal coating on the boards protects against the condensation that sealing cannot prevent when a cold switch meets warm air.

MIL-STD-461G sets limits on what equipment emits and what it must tolerate. The requirements that apply depend on the platform, ground vehicle, aircraft, ship or fixed installation, but a switch is usually tested against the following.

Ethernet itself is reasonably robust, but a switch on a vehicle sits beside radios, motors and jammers, and its cables run past them. The related standard MIL-STD-464 covers electromagnetic effects at the level of the whole platform.

Platform power is hostile: spikes, surges, ripple and electromagnetic noise that a commercial switch is not built to tolerate. A ground vehicle’s 28 V DC bus is the classic case. The figures below are the commonly quoted MIL-STD-1275E limits for 28 V DC systems; the standard itself defines the exact waveforms and durations.

Aircraft use MIL-STD-704 instead, which defines normal, abnormal and emergency limits for 28 V DC and 270 V DC systems, among others. The answer in both cases is a dedicated power front end. Diamond Systems pairs its switches with board-level military power supplies that add galvanic isolation and input filtering to the requirements of MIL-STD-461, MIL-STD-704 and MIL-STD-1275, so the switch runs cleanly from the platform’s 28 V DC supply without polluting the network or the vehicle’s electrical system. The same family of supplies powers PC/104 stacks; see our PC/104 power supplies.

The network core is a board-level managed switch from the Diamond Systems range, up to the EPS-9600 with its Time-Sensitive Networking capability and IEEE 1588 PTP. Building on a proven board rather than custom silicon takes the risk out of the design: you get managed Layer 2+ switching and Layer 3 routing, 1G and 10G ports (copper or SFP, broken out with transceivers), and determinism features, on a board already sized for integration. Our guide to OEM Ethernet switch modules and board-level switching covers how that core is chosen and what a carrier board needs.

The board is paired with the military power front end described above: isolation between the platform supply and the switch, filtering in both directions, and enough hold-up to ride through a cranking dip. On Diamond’s complete switches this is a build option. The SabreNet-12000-200 and -220, for example, use a power supply based on Diamond’s JMM-7500 that provides compliance with MIL-STD-461, MIL-STD-704 and MIL-STD-1275 with 500 V isolation between input and output, while the -100 and -120 builds use a MIL-STD-461 filter in a lower-profile case.

The electronics go into a rugged build: a solid-body aluminium enclosure, MIL-DTL-38999 circular connectors in place of RJ45, conformal coating against moisture and contaminants, and fanless conduction cooling for −40 to 85 °C operation. The assembly is built and tested to the requirements of MIL-STD-810 for shock and vibration and sealed to an IP rating suited to where it is deployed. Our guide to the types of Ethernet switches compares the connector and management options across rugged switch types.

The switch is configured for the network it will run: VLANs, QoS, redundancy and, where the application is time-critical, TSN scheduling and PTP timing, which our TSN guide explains. It is integrated with the rest of the system, including the mission computer it connects to, and delivered tested and ready to deploy rather than as a box to be wired up and configured on site.

Connectors decide how a switch is cabled, sealed and serviced. On a military switch the ports are usually grouped onto a few circular connectors, each carrying four to eight Ethernet links, with breakout cables to the devices.

Our FAQs on X-coded M12 and single-mode vs multimode fibre help with the choice between copper and fibre uplinks. Fibre is immune to the electromagnetic noise around a vehicle and carries 10G over long runs, which is why some military switches offer it on their fast ports.

A vehicle or shelter network carries video, sensor data, voice, command and control and maintenance traffic on the same cables. The managed features below keep them apart, keep them moving and keep them secure.

Our FAQs on VLANs, IGMP snooping, RSTP and Precision Time Protocol explain these features, and our article on IEEE 1588 for machine vision shows why shared time matters when several cameras and sensors feed one computer.

The platforms differ in power, space and environment, which changes the switch they need. The rows below are typical, not fixed rules. Size, weight and power, often written SWaP-C with cost added, drives most of the choices.

Military switches usually sit beside military computers and military monitors on the same platform, all built to the same standards. Ship systems also call up MIL-STD-167-1 for shipboard vibration.

Diamond Systems builds the switches below; we supply them and help you specify the build. All figures are from Diamond’s published information in our catalogue. The Diamond range does not supply PoE; where a rugged network has to power cameras, the M12 PoE switches in our military and rugged Ethernet switches range are designed to railway and industrial standards rather than MIL-STD.

The EPS-9600 is a switch board rather than a sealed switch: it uses the PC/104 mounting hole pattern and goes inside a mission computer or a rugged enclosure. The wider family of Ethernet switch boards gives other port counts on the same principle.

An integrated build gives an exact fit: the right ports, connectors and power for the platform, rather than the closest catalogue match. It brings a single point of accountability for the switch, its power and its enclosure, a build qualified against the standards the programme needs, and a supported lifecycle for the years a defence platform stays in service. It is the difference between a switch that happens to fit and one built to belong on the vehicle.

Diamond can also change the connector arrangement, cabling, coatings and software branding on its complete switches, which narrows the gap between a catalogue product and a custom design. Where nothing in the range fits, the same board-level switching is the starting point for a custom build.