Military Embedded Systems

Unmanaged vs. managed Ethernet switches for modern warfare applications


October 16, 2014

Ronen Isaac


In today's modern warfare – where survivability and mission success is dependent on data acquisition, analysis, and instruction – a growing number of Ethernet-based devices supporting missions must be connected to the central mission computer, and often to each other. Ethernet switches are needed throughout military infrastructure as a common means of making such connections. Customers often ask us whether they need a managed or unmanaged switch. Let's go through the basic capabilities of each.

Unmanaged switches are simple connectivity devices that provide no configuration interface, network management, or control over data flow. They're generally used for networks in which data prioritization isn't a concern and overall data traffic and the number of connected devices are low. These switches are plug-and-play and are well suited for smaller or less complex applications such as dismounted soldier or SUAS, where devices just need to be able to communicate with each other. Unmanaged switches can't be configured locally or remotely according to a network's requirements. Unmanaged switches often come with LED indicators to help you verify that there's connectivity between the port and the Ethernet cable. But that's it. In short, unmanaged switches are simple yet functional.

Today's managed Ethernet switches provide key features to support today's applications. Primary among these are quality of service, VLANs, spanning tree, and port mirroring. Each application that uses an Ethernet network has inherent requirements for its proper operation.

As examples, digitized audio (voice over IP, or VoIP) connections require very little bandwidth, but are sensitive to delay (called latency) and to the variation in delay, called jitter. Video connections are likewise sensitive to latency and jitter and can use significant bandwidth. Managed switches can help ensure that the VoIP or video packets have the low latency and jitter required by implementing quality of service (QoS). QoS is also known as traffic prioritization and is used to identify important traffic on the network to give it right of way. In addition, managed switches provide the ability to monitor each device on the network as well as limit the amount of bandwidth any device can use.

Another widely used feature of a managed switch is called Virtual Local Area Network, or VLAN. When implementing VLANs on a managed switch, you are, in essence, creating logically separated, individual switches on the same switch hardware. That means that devices on one VLAN can't communicate with devices on another VLAN without using a router. This is ideal for segregating or isolating networks such as red and black or isolating which users on a network have access to which devices. Along with restricting traffic, VLANs can also identify data types and apply proper QoS settings to each of them.

Managed switches are remotely programmable via web or command line to allow pre- and dynamic configuration. Multiple switches provide redundancy and eliminate the possibility of a single point of network failure. The switches are interconnected so that the failure of a switch or link between switches can be automatically rerouted. Switches use spanning tree and other algorithms to implement redundant paths and sometimes balance network traffic.

So if your network is restricted to a few devices and there's no need to prioritize traffic for unimpeded flow, an unmanaged switch is the best choice. Examples for best usage of unmanaged Ethernet switches include connecting sensors or a small amount of video cameras that won't saturate the bandwidth. On the other hand, a managed switch is best suited for networked devices where certain devices or traffic need priority over network bandwidth on saturated bandwidth, be on virtual LANs, or bandwidth usage must be monitored.

Today, your choices for Ethernet switches are limitless. Whether you need them contained within MIL-SPEC housing, board-level devices, or traditional housing. As new data-centric devices are required in space-constrained environments, you should not only be concerned with the basics of managed vs. unmanaged, but the size, weight, and power (SWaP) requirements of these switches. This is where your true differentiation will come in to play.

Ronen Isaac is the General Manager for MilSource, a distributor of the Techaya line of MIL-SPEC Ethernet switches.


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