Network Traffic Issues

[RBPLC]

I saw something this morning I haven't seen before concerning network traffic. This is currently in bench test and I'd appreciate any information. One caveat here is that I have little experience troubleshooting network traffic. I realize the below is not ideal and the final configuration will not match the below, I'm just curious as to what's going on and relatively easy troubleshooting steps to understand the traffic.

Setup:
1 unmanaged switch sitting behind a managed switch.
Attached to this unmanaged switch is one laptop, one desktop, 2 BRX's and 2 C-More Panels. The two C-More panels are communicating with one of the BRX's at full speed (over ethernet). The other BRX is communicating with another remote device over Modbus TCP. On the desktop I have two instances of DMD pulled up (one for each BRX) with All Status turned on. It so happened that on the laptop I starting transferring a large file to a network folder (~3 Gb). When I did this, I started getting comms failures all over the place. Comms failures from C-More to BRX and comms failures from desktop to BRX's. Both BRX's comms started dropping (including the one not communicating with the C-Mores). The ethernet lights on the BRX would drop every few seconds, come back on and then drop again. When I stopped transferring the large file, comms cleared up. Trying to transfer the file again, comms started dropping again. This time I turned No Status on for each BRX in DMD and comms cleared up. All this being said, what general type of problem does this sound like? Are there ways (even in this less than ideal setup) to shore up comms between the devices? In the final configuration all of these devices will not be on the same unmanaged switch.

[franji1]

I definitely misspoke.  The only way to know for sure what is going on is to monitor the traffic (e.g. WireShark).

The PC's Ethernet port itself can get bogged down if its trying to do too much comm.  We have seen Windows/Browsers try to govern applications' Ethernet bandwidth, which could affect Designer throughput.

Unmanaged switches send packets out all of their ports.  Hence, EVERY PLC was receiving your large file transfer packets at the rate a PC can send packets (even though they are not targeted there).  So, Ethernet packets are being processed by the Ethernet PHY on every PLC, not able to process ACTUAL packets that are targeted, causing a delay of good packets.

Realize PCs are MUCH FASTER than PLCs (lots of processor cores, lots of threads, lots of memory) able to transfer packets VERY FAST.  Not sure of the bandwidth of your PC/file transfer packets (cuz everybody loves FAST file transfers, even if it saturates an unmanaged network).

Replace your UNmanaged switch with MANAGEd, and that should reduce the issues.  OR bump up the timeouts of all your devices reporting errors, but the update times on those devices will be SLOWER compared to when you are NOT transferring large files.

[www.SystemsIntegrator.mobi]

When I open C-MORE designer and DO-MORE designer at the same time I get errors as well


When I open DO-MORE  designer and Do-MORE designer at the same time I get erros as well


Maybe try buying another computer for the Second DO-MORE designer running this works for me