Industrial Ethernet Device Level Ring Support

[RICHARD MESSINGER]

Have a potential customer that is looking at the IE2000 series switch and at the Rockwell Allen Bradley switch

Question is does it support Device Level Ring (DLR) capability.  I do not see this specifically mentioned in the Data Sheets but it talks about a

Resilient Ethernet Protocol (REP) and I am wondering if this is the same thing?

Thanks

[Pawan Sharma]

Hi,

had tried to read about these two technologies, they look similar but there working mechanism is entirely different. i am sure this URL would help you -

http://www.iebmedia.com/index.php?id=6113&parentid=63&themeid=255&hft=52&showdetail=true&bb=1&PHPSESSID=ubr8m1p2absmvf1c147pvqr6t0

Regards,

Pawan Sharma

http://www.ebrahma.com

[Brad Johnson]

DLR refers to the abandonment of physical switches and using the embedded dual ports on the Rockwell devices.  It uses the end devices to create the ring.  Neither the Stratix family of switches or the IE-2000s pertain to this.  The new CompactLogix controllers that Rockwell has come out with as well as some of the drives (PF 753/755 and 525) support this either natively or with option cards.  Also, any Rockwell device that I know of that ends in an "R" (for Redundacy) supports DLR (i.e.  1769-L16ER, 1769-L33ER, 1756-EN2TR).  The only physical switch that I know of that is made for a DLR is the Allen-Bradley 1783-ETAP module which is made to allow the ring and only have one additional port for the device.  I hope this helps.

-- Brad

[Robert Ulmer]

Stumbled across this post and want to chime in....

REP and DLR are two different protocols. REP is 'owned' / managed by Cisco and DLR (Device Level Ring) is 'owned' by ODVA (Open Device Vendors Association).

REP is fully supported across the IE2000 (and IE3000, IE4000, and IE5000 for that matter) and Stratix 5700 (and Stratix 8000, 8300, 5400, and 5410) switches. REP is a series of 'segments' that can be formed into a ring, or many other topologies as well. REP can reconverge in ~50-70 mS based on topology and media in use (gigabit fiber is the fastest).

DLR is supported in the Stratix 5700 (limited to specific catalog numbers...), Stratix 5400, and quite possibly their Cisco 'sister' switches, in addition to the ETAPs and the 'R' devices mentioned in one of the other posts. DLR is a DEVICE Level Ring and should not be used as a network trunk / backbone. A 50 node DLR ring can reconverge in under 3 - 4 mS so it is very fast and will allow for most connections to NOT be dropped on a single failure in the ring.

I hope this helps clear up the differences.

[BrianSekleckiGE]

I'm hoping to run some tests on the supposed-answer to this question in my lab soon:

The question I have on my mind: DLR Ethernet frames have EtherType = 0x80E1 and are untagged.

Does this affect how they are switched (such as in a Bridge Domain, Q-in-Q environment, or a standard VLAN?) and forwarded in a Catalyst environment?  

[Sergey Prishchepa]

https://literature.rockwellautomation.com/idc/groups/literature/documents/td/enet-td015_-en-p.pdf