In this article we will be implementing Layer 2 NAT with Layer 3 routing as shown in the the network topology depicted below. For this example we will be leveraging two Allen-Bradley Stratix 5700 Managed Industrial Ethernet switches (Full Software Version) and three Logix based controllers (machines).
With Stratix 5700 NAT capability configured, we can setup a NAT instance per VLAN. When we create multiple VLANs on one Stratix 5700 switch we can connect multiple identical machines and leverage Layer 3 routing to route between the various VLANs.
If you’ve not seen our article showing you how to initiate the Express Setup mode on a Stratix 5700 switch, you can view it here before proceeding. Also, we have created an in-depth article and video tutorial on how to effectively configure and implement Inter-VLAN Routing on a Stratix 5700 switch here. Both of these articles and video tutorials are highly recommended before proceeding with this article as we build upon and rely heavily on those foundations.
The first thing we’ll need to do is perform an Express Setup on the first Stratix 5700 switch. Once in the Express Setup mode of the Device Manager, assign an IP address to your router and enable the routing functionality on the switch. This has all been covered in explicit detail in our Stratix 5700 Inter-VLAN Routing article.
Configure your router with the following IP address assignment, we can continue on to configuring the necessary VLANs needed to implement our network design.
To implement our network we will need 2 VLANs for the 2 identical machines (Machine 20 and 21). One VLAN for the Line Controller and the default VLAN for the management of the switches.
Enable the routing capabilities of the Stratix 5700 by going to Admin and then select SDM-Template. Select Lanbase Routing and press Submit. The switch will reload with the SDM -Template for routing.
Go to the Routing page to Enable Routing between VLANs and press Submit.
In our network example above the line controller and the PC are connected to the router. That means that we have to set the
Smartports and the correct VLANs on these two ports.
With this information select the proper Smartports on the router.
The PC is connected to VLAN1, no changes needed here. The Line controller is connected to VLAN20 so we need to change the VLAN number for port Fa1/1 from the default to VLAN10.
Go to page Configure and then Port Settings. Change the VLAN number for port Fa1/1 to VLAN10. Everything else remains on VLAN1 as configured.
The configuration of the router is finished.
At this time we can check if the routing is working by pinging the line Controller. Connect the Line controller to Port Fa1/1 on VLAN10 and your PC to Port Fa1/16.
Ping from your PC to the IP address of Line Controller 172.16.10.10. If it doesn’t work check your settings again.
Perform the Express Setup now on the second Stratix 5700 NAT switch.
Notice we have the gateway for the default VLAN configured in this Stratix 5700 NAT switch to allow it to communicate with other VLANs.
Now similar to what we did in the router we need to configure all the VLANs needed on the Stratix 5700 NAT Switch.
Now configure all the Smartport on your Stratix 5700 NAT Switch.
Go to page Configure and then Port Settings. Change the VLAN number for the ports as shown.
The last step is to create the NAT instances for the different machines. Go to Configure and select NAT. Create a new instance and do the same as in the screenshots below. Do the same VLAN configurations for both Gi1/1 and Gi1/2. This means that you can use both ports to connect your switch to the upper network.
Press Submit to save the configuration.
At this point you should be able to ping the Line Controller and both Machine 20 and Machine 21 from your PC as shown.
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