Why Producers duplicate IPv4 addresses and the way IE switches assist resolve the problems


If this matter piqued your curiosity, you’re in all probability impacted by or a minimum of interested in duplicate IP Addresses in your industrial community. You aren’t alone. It may be a bit of bewildering. There doesn’t appear to be any cause at the moment to have duplicate IP Addresses, not to mention do it on function. Let’s unravel the thriller.

Corporations that construct refined machines have made the transition to Web Protocol because the communication protocol inside their machines. IPv4 is the simplest protocol to make use of. There are many software program libraries within the ether primarily based on IPv4. These corporations’ core competency is {the electrical} and mechanical facet of their machines, not the software program that runs the machine and due to this fact they don’t have refined software program groups. If you’re writing communication software program and software program just isn’t your core competency, what’s the best and least problematic method to determine the elements inside your machine? Reply: Static IP Addresses. The choice to static IP Addresses is a extra sophisticated course of involving dynamic IP Tackle project, together with a fancy job of figuring out which IP Tackle the person elements acquired.

The IP Addresses had been duplicated on function. The software program within the machine makes use of static IP Addresses to determine particular person machine elements as a result of it’s simpler for the machine builders. Every machine they construct has the identical software program (SW). Due to this fact, they use the identical static IP Addresses. When you’ve got bought two or extra of their machines, then you’ve duplicate IP Addresses. To be truthful, it might be a lot more durable and price prohibitive to provide every element of every machine a singular IP Tackle.

Determine 1: Robots symbolize a number of machines with an identical elements and software program

The robots within the image above are an instance of a classy machine. Every robotic has the identical elements and the identical software program. Every element has its personal statically assigned IP Tackle. This follow just isn’t restricted to robots. Bottling machines and diaper making machines are manufactured in the identical method.

Why is that this an issue?

So long as you possibly can include the broadcasts of IPv4 Addresses of the elements to remain throughout the machine, try to be OK. There’s all the time one publicly distinctive IPv4 tackle on the machine which represents the whole machine to the skin world. Once more, so long as you solely use this one IPv4 tackle to speak with the machine, it shouldn’t current any issues. More often than not that is the way it’s completed and everyone seems to be glad.

Alongside comes the necessity to enhance productiveness. To extend productiveness, you want extra knowledge. And the place is that this knowledge? One place is contained in the machine. Now you want to talk with the elements contained in the machine. Upon getting a couple of machine, how do you have to talk with the interior elements which have the identical IPv4 tackle? That is the issue.


Earlier than describing options, I’d wish to uplevel the dialogue to speak about Community Tackle Translation (NAT) normally.

Everyone ought to learn about NAT. We use NAT daily whether or not we all know it or not. The IPv4 router in our properties makes use of NAT. The IP Tackle assigned to your private home units (together with your laptop computer and smartphone) is a personal IP Tackle. This non-public IP Tackle just isn’t routable on the Web. Our neighbors all have in dwelling units with the identical IPv4 addresses. It’s not an issue as a result of our dwelling routers use Community Tackle Translation (NAT) to transform non-public IP Addresses to a publicly routable IP Tackle so we are able to talk with units on the Web. The Web service suppliers use non-public IP Addresses for in dwelling use as a result of it’s simpler for them. There usually are not sufficient IPv4 addresses on this planet for each IP succesful gadget to have a singular IPv4 tackle. And let’s face it, we have now not transformed to IPv6.

Your house just isn’t the one place NAT is used. Industrial networks additionally want to make use of NAT as a result of refined machines have the identical IPv4 addresses.

There are actually solely two methods to unravel duplicate addressing issues for industrial networks. The obvious method is to insert an extra Layer 3 gadget akin to a firewall or router between the machine and the remainder of the community—simply to translate Non-public IP Addresses. That is much like what you’ve at dwelling. This answer requires a particular community gadget for the aim to transform non-public IPv4 addresses to publicly distinctive IPv4 addresses. The disadvantage is, that it’s an extra gadget to buy and handle and, configuration and administration of this Layer 3 community gadget will be advanced, requiring somebody with IT expertise to setup and keep them.

The much less apparent method is to make use of a Cisco Industrial Ethernet (IE) change to do the IPv4 translation. When the IE change solves the duplicate IP addressing drawback, it’s utilizing Layer 2 NAT. Plus, in my biased opinion, configuring Layer 2 NAT on a Cisco IE change is simpler than configuring NAT on router or firewall. There’s in all probability an Industrial Ethernet change in your community already connecting all of the machines collectively. Why introduce an extra community gadget? Hold the identical easy community structure you’ve with a Cisco IE change and resolve your duplicate IPv4 addressing points, too.

Determine 2: IE-4010 connecting a number of advanced machines

In determine 2 above, every robotic has the identical IP Addresses for its inside elements. The Cisco IE change will translate the duplicated non-public IP addresses of the elements of every robotic (ie: advanced machine) into publicly distinctive IP Addresses because it receives the Ethernet frames from the robots.

Pattern IOS CLI configuration for the Cisco Industrial Ethernet

That is how you’d configure a Cisco Industrial Ethernet change to offer L2NAT for the primary two robots on the left in Determine 2. The remaining three robots can be similar to the primary two.

You begin by defining which IPv4 Addresses to translate. The Cisco IE doesn’t know which publicly or non-public IP addresses you need to use. It’s a must to inform it. You outline the whole translation.

Outline a translation occasion for every robotic. The ‘leftmost’ robotic would have this translation occasion for 3 of its inside elements. The ‘nextleftmost’ robotic would have the identical non-public IP Addresses however distinctive public IP addresses.

Observe: The IP Addresses for the within hosts are the identical in every of the 2 translation cases, and the translated public IP Addresses are distinctive. They need to be distinctive if they’re for use within the upstream community to uniquely determine the robotic elements.

The subsequent step within the configuration course of is to use the interpretation cases to the proper interface. The ‘leftmost’ robotic is linked to port Gi1/2, and the robotic subsequent to it’s linked to Gi1/4.

Disclaimer: This configuration, whereas legitimate, is simply an instance.

In the case of configuring something within the IOS CLI, the instance above exhibits how easy it may be. For these of you who don’t like utilizing the IOS CLI, the identical configuration will be completed utilizing the IE’sweb primarily based GUI.


For these of you searching for an answer to the duplicate IP Addressing drawback, utilizing the IE change you have already got in place simply is sensible. For these you with out an IE Change, now you’ve an excuse to deploy one within the entry layer. Particularly if in case you have unmanaged switches within the entry layer at this time. Utilizing an IE change is a one field answer. The IE switches do the IPv4 tackle translation at line charge. In addition they translate the IPv4 addresses within the payload for ICMP and ARP.

L2 NAT is simply one of many many options on Cisco’s IE switching options that resolve buyer points with high quality and reliability.

Get extra data on Layer 2 NAT

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