Question about Network Traffic Separation

So whenever I have been working on new projects, and need remote IO, I typically install 2 network cards In the backplane and create 2 separate networks, 1 for the remote IO and one for the main network.

I have a situation where that didn't get done, and seems to be adding too much network traffic. I have an L72 PLC with a full backplane and only 1 Ethernet card. and a remote backplane with 9 full slots and again only 1 Ethernet card. I have 2 managed Hirschmann RS-20 switches, one that wasn't needed, and one that is completely full of devices, including a line back to the main network switch.

My question is basically this, is it possible (using IGMP ?) to separate the traffic between the remote IO and the PLC, but still have access to the PLC from the main network, using only managed switch with the correct settings? Otherwise, the only way I know to do this would be to buy a bigger backplane, and install a 2nd Ethernet card.

I have attached an image better explaining what I have. The green highlighter showing traffic that needs to be separated from the blue highlighter.
any tips or suggestions would be much appreciated!

-Joel

I am by no means a network guru but to segregate our traffic we use a Vlan setup.
One for I/O, one for PanelView traffic, and one for general traffic.

Edit: By setting the priority for each Vlan you can decide what data get routed first.

Depending on your managed switch, you can configure some ports as 'protected' and limit which ports can 'talk' to each other.

Then, limit the remote i/o port to only being able to have traffic forwarded to it from the PLC port.

I think most people over-estimate the network traffic load for PLCs. If it's managed switch then you should be able to see the CPU load on them, most of time, they aren't even close to being overloaded.

The switch is already segregating the traffic and preventing PLC broadcast traffic if it's IGMP Snooping enabled.

harryting said:

I think most people over-estimate the network traffic load for PLCs. If it's managed switch then you should be able to see the CPU load on them, most of time, they aren't even close to being overloaded.

The switch is already segregating the traffic and preventing PLC broadcast traffic if it's IGMP Snooping enabled.

Click to expand...

Currently, there are no enabled features in the switch.
You're saying if I enable IGMP Snooping/Multicast, It may do this for me automatically anyways? (As of right now, I'm seeing all this traffic between the PLC and the remote IO on the main network, as if it were travelling all the way to the main network switch and back again.)

If the switch works correctly, enabling IGMP Snooping should prevent the Remote/IO traffic from reaching the main network. That is how the switches on our equipment are setup.

are you using unitcast or multicast for the remote IO Ethernet/IP (CIP) protocol communications?

As lynx mentioned you can set the quality of service priority higher on the ports with the PLCs if there is too much traffic on the switches, but if that is the case you have bigger problems.

people separate traffic on the same switch using VLANs mostly because it makes it easier to apply QoS. Separating the traffic on VLANs without using QoS has no impact on performance.