Is it possible to use an SD+ in redundant star networks (PRP)?

Created by Patrícia Siqueira, Modified on Mon, 8 Jan at 11:44 AM by Patrícia Siqueira

The SD+ is a feature gateway with a single network interface, allowing only physical redundancy, as described on this page, available on our platform.

The PRP (Parallel Redundancy Protocol) is a standard Ethernet protocol for any type of redundancy, including protocols such as PROFINET, IEC61850, EtherNet/IP™, DNP3, IEC60870-5-104, Modbus/TCP, as well as other protocols above Ethernet Layer 2.

To enable the use of one or more SD+ in PRP networks, it is necessary to use a Redundancy Box, also known as RedBox. The RedBox enables the inclusion of equipment with a single network interface (Single Attached Node - SAN equipment) in redundant star networks. In a simplified manner, the RedBox receives the frame from the SAN device, duplicates it, and forwards it to the two LANs. The RedBox also receives redundant frames from the two LANs, with the first one received being forwarded to the SAN device, and the second one being discarded.

Below are examples of architecture and their implications, considering the desired solution for this project:

Example 1

This is the simplest case; a single RedBox will act as a switch in the network highlighted in blue and provide redundancy in protocol for networks A and B.

Example 2

This case is similar to the first one but with a ring topology in the network highlighted in blue. The positive aspect would be physical redundancy in this network. It's important to note that for this alternative, the RedBox must be configured to manage broadcast storms.

Example 3

In this possibility, in addition to the ring network, there is redundancy of RedBoxes. Similar to the last case, the network should be managed to avoid broadcast storms.

Example 4

In this last case, there is protocol redundancy available for each SD+ separately. However, for this possibility, a larger quantity of RedBoxes must be purchased. This alternative is recommended primarily for contexts where there is a limited number of ports in the RedBox and no control over broadcast storms.