PLCGuruAgree with Jeff on this one (as I chuckle to myself hearing the underlying synacism – when you’ve been around the block and seen the way things go it’s hard not to be sometimes :).
But yes, a DLR by definition, is a “Device” Level Ring so it is most practically implemented at the work cell level to provide a level of redundancy in your automation cell.
For your backbone switches this will typically be handled by “true” layer 3 switches handling your trunk lines and inter-vlan routing. This is the IT to OT bridge if you will connecting your factory floor to your business intelligence systems.
Enjoy your weekend boys!