Diff Ethernet Protocols on One Network

Timeismoney08

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What happens if you put Ethernet/ip, Modbus TCP, and Profinet on the same network? Do they need to be isolated from each other or can they work on the same network?

Thanks for the help!
 
Why would they not work on the same network?

What you may find is that potentially they won't work as well as if being isolated from the network, but I would say that will be due to traffic.
I would say off the top of my head that unless you're doing motion control you should be fine.
 
Of course, several protocols can share the same subnet, just as in a computer you can have several programs with different protocols running at the same time
 
Why would they not work on the same network?

What you may find is that potentially they won't work as well as if being isolated from the network, but I would say that will be due to traffic.
I would say off the top of my head that unless you're doing motion control you should be fine.

Well I know EtherCat specifically says not to. It can work, but more than likely you will suffer latency and possibly cause errors. I just wasn't sure about other protocols out there.
 
Well I know EtherCat specifically says not to. It can work, but more than likely you will suffer latency and possibly cause errors. I just wasn't sure about other protocols out there.

As cardosocea, you will really only run into problems if you are running a time-sensitive protocol like EtherCAT or CIP Motion. It may still work if you have a properly configured managed Ethernet switch but it CAN be tricky to keep stable.
 
Modbus/TCP and Ethernet/IP can coexist on the same link. I've done it.



I was under the impression that Profinet requires its own connection because its deterministic nature requires solo command over the link.
 
As others have said different protocols can reside on the same subnet. Thats what "Ports" are used for. Modbus/TCP (and UDP for that matter)uses port 502, whereas Telnet is port 23. This is why i can Telnet to a device on a subnet while other devices on the same subnet can continue their Modbus/TCP traffic unimpeded. Some ports are "official" or "reserved" by IANA to keep different platforms or protocols from colliding essentially. If you are concerned about potential issues, investigate the TCP and UDP port usages for the different protocols in use on a common subnet.

A certain mfg or OEM may not recommend implementing multiple protocols on a single subnet due to bandwidth issues. For instance VOIP is a UDP protocol. VOIP will continue flooding a subnet with packets regardless of if they are received by the destination IP or not. You probably don't want VOIP running on the same subnet as your automation subnet. VOIP would eat up a bunch of your bandwidth and slow down your automation protocol.
 
If you have to do something like time-sensitive traffic on the same network, enable QoS with managed switch. Of course, it's usually better to do it on a dedicated network.

related to this topic, I noticed a change in recommended architecture on a recent Rockwell/AB presentation. In the old days they recommend separate IO/HMI network, now they recommend doing that using VLAN and not separate physical network.
 
related to this topic, I noticed a change in recommended architecture on a recent Rockwell/AB presentation. In the old days they recommend separate IO/HMI network, now they recommend doing that using VLAN and not separate physical network.

Now they can sell you switches that can do that :p
 

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