DLR- "Partial Network Fault" status

[AlfredoQuintero]

Hello.
This one is as nerdy as it can get. Never seen this issue before.
I am seeing a "Partial Network Fault", for which the specification only says: Vol 2, Clause 5-6.3.4 Network Status Values:
"A network fault has been detected in one direction only. Valid only when Network Topology is Ring and the node is the active ring supervisor"
The catch is, I am not using a normal DLR, but the DLR as specified in the ODVA test specification for DRL node. This environment used to work but now I see this very strange behaviour.
I have tried to show what I have in the screenshot below.
Interestingly, if instead of switch B I use and unmanaged Ethernet tap the ring goes to normal status.
In this strange partial network fault condition, the activity LED in the port of the next node in the ring, connected to the L13ER supervisor is flashing, but the LED in the L13ER itself is off!
As you can see in the screenshots there is traffic on both switches, so I do not understand why the activity LED in the L13ER is not flashing. Really interesting,
I am intrigued about what can be the reason for this strange situation.
I am using LAN cables with only four lines between the DLR devices and the managed switches, so all ports in the managed switches including from the managed switches to the PC go online at 100 MBps Full duplex, so I am ruling out PHY issues.
Anyway, thanks for reading to this point.

 

[harryting]

This is above my network knowledge. I thought DLR is proprietary to AB so one can't use a switch, even a managed one to act as a DLR node.

 

[AlfredoQuintero]

DLR is part of the specifcation. There are other makers such as Phonenix Contact which support DLR node and supervisor.
That is a special setup dfor the conformance test of DLR devices. It is not used in actual machines.

 

[Contr_Conn]

Let me start saying that I know nothing about conformance test.
As far as I know, only DLR enabled devices can be part of the network and switched must have DLR ports (like Stratix) to participate.
Partial network fault related to the beacon been passed one direction only. I guess your non-DLR switches don’t pass it correctly.
You probably need to contact ODVA conformance people for help.

 

[AlfredoQuintero]

Hello Contr_Conn:
Thanks very much for your comments.
You may not know about the DLR conformance test, but you know more device-level ring technology than anybody I know, and have been so helpful to me in the past with my questions.
You are right. I have analyzed the data in more detail. It seems the switch A is not passing the beacon from the DUT. As you can see below, the trace in switch B shows the beacon pairs, while the trace on switch A shows only one beacon. With this understanding, I can think a bit more about it before I ask ODVA. This think used to work so I think I should be able to fix this.
Again, thanks for sharing your knowledge.
The purpose of my question was to understand the meaning of "partial network fault" in the DLR context. This I have achieved thanks yo your explanation.

 

[JeremyM]

Good discussion.

 

[AlfredoQuintero]

Contr_Conn and JeremyM:
Thanks a lot for the follow-up and interest.
I got the system to work as expected. The screenshot below shows what normal DLR beacon packets look like.

I think the ODVA could spend a bit more time explaining what the required settings for the managed switches should be. It is not trivial.
Again, thanks very much to Contr_Conn for sending me through the right path.

 

[Contr_Conn]

My only ask, is not to use monster screenshots like these.
Almost impossible to see on the cell phone or iPad screen.

 

[JeremyM]

That Molex tool is so handy.

 

[AlfredoQuintero]

My only ask, is not to use monster screenshots like these.
Almost impossible to see on the cell phone or iPad screen.

will keep this in mind.

 

[AlfredoQuintero]

That Molex tool is so handy.

For me this tool is invaluable.