What is DLR? What is Device Level Ring?

What is DLR? What is Device Level Ring?

DLR, or Device Level Ring, is an Ethernet/IP protocol introduced by ODVA. We can utilize DLR switches exclusively within Ethernet/IP networks.

Put simply, if you have a device intended for a single port, originally designed for Line and Star network setups, and you wish to incorporate it into a ring network, a DLR switch can seamlessly integrate that device into the ring.

For a clearer understanding, let’s take the example of a Mitsubishi VFD that operates with Ethernet/IP as its communication protocol.

It supports only star and line topologies; ring topology is not available in it.

However, I intend to connect it to a ring network. In this scenario, the solution is to employ a DLR switch, sometimes referred to as an E-Tap switch.

Line Topology-Ethernet/IP -Mitsubishi VFD

Star Topology Ethernet/IP: Mitsubishi VFD

To connect a Mitsubishi VFD into a ring network, a ‘DLR Switch’ is required.

An example of Device Level Ring utilizing an E-Tap switch: Mitsubishi VFD connected to a ring network is depicted in the image below.

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