Fiber ring and profinet

We have a fiber ring in the field with Moxa EDS-405A switches at each node.

I'm wondering if we can have profinet sub rings at each node or if the switch needs to explicitly support profinet. Can profinet devices see each other across nodes if the switch does not explicitly support profinet?

I think I read MRP requires all devices to support MRP. Does that mean I need to find switches that explicitly support MRP or Profinet?

plumbo said:

We have a fiber ring in the field with Moxa EDS-405A switches at each node.

I'm wondering if we can have profinet sub rings at each node or if the switch needs to explicitly support profinet. Can profinet devices see each other across nodes if the switch does not explicitly support profinet?

I think I read MRP requires all devices to support MRP. Does that mean I need to find switches that explicitly support MRP or Profinet?

Click to expand...

In my experience, switches tend to only support being a part of one ring. Generally, multiple rings that overlap are considered a mesh. There are mesh network options, like RSTP, but they tend to have slower reconfiguration times than a simpler ring protocol would.


Switches would explicitlu need to support MRP, if you want it to be an MRP ring. If you want to use a different ring protocol, then the rings would need to support that protocol.



Generally, switches will transmit Profinet traffic without specific support, but there can be exceptions. Profinet is built out of a suite of different protocols, including some general Ethernet standards. If the switches do not support LLDP (or have it turned off), then the Profinet Topology functions won't work correctly. Some brands of switches require a special QoS mode to be active to allow the Profinet data to be transmitted, as it is transmitted in VLAN 0: Priority only, no VLAN. By default, these switches block traffic in VLAN 0.