- So now we're going to talk in general about virtual network concepts. What is a virtual network and how do I create one and what do I need it for? What good does it do me? Well, what a virtual network is, an overlay. It sits on top of what we already have. And what is it that we already have? Well, for one thing, it's the vSphere Distributed Switch. A vSphere Distributed Switch is what ties everything together. If you know a little bit about vSphere, you know that when you add hosts to a vSphere Distributed Switch and then you add a distributed port group to the vSphere Distributed Switch, the distributed port group is automatically connected to all of the hosts.
We're going to leverage that concept, and that's going to be the glue that is going to allow us to tie everything together. So we're going to create this overlay, this software network that will sit on top of the physical network. And that way, we can control where traffic is allowed to go when it's inside of the software network. And we can control where it's allowed to come back out, where in the physical environment it's allowed to come back out, which gives us a lot of control in the software that we don't currently have.
So what we're building are new layers. If you think about, you know a little bit about the OSI model, just general networking. The OSI model is seven layers. Application, presentation, session, transport, network, data link, and physical. Well, when we get done, we're going to add two more layers. Really we're just going to replicate layers two and three again. So when we get done, it'll be application, presentation, session, transport, network, data link, network, data link, physical.
We're going to put a new logical layer two on top of our current layer three, which means we can connect routed environments to each other in ways that we haven't thought of before. And then we're going to have a new logical layer three that'll do things that our current logical layer three won't and we'll discuss what those are. And we're going to be able to use any hypervisor, but we're going to focus on vSphere. But we can use other hypervisors for this technology as well. In addition, once we have this virtual network in place, we'll have our own logical firewalls, we'll have our own logical load balancers, and our own logical VPNs that we can use.
You can choose to use those or you can choose to use what you already have. Let the traffic flow back out of the network and go to those devices that you already have. And we're going to be able to manage it with any cloud management platform, and we're going to be able to use any application on our new network. Now why can we use any application on our new network? Well, because the workload that is the application is just going on to what it expects.
It doesn't know that it's going on to a virtual network. Just like with a virtual machine, the guest operating system that's on a virtual machine when we're doing full virtualization with vSphere, the guest operating system on a virtual machine does not know that it's on a virtual machine. It thinks it's on a physical machine. And therefore, we don't have to change any applications. By the same token, the workload that we're going to put onto the network does not know it's going onto a virtual network. And when it comes off, it never knows it was on a virtual network.
Therefore, we don't have to change the application at all. But the kind of cool things that we can do are because of the fact that we have all of our routing, our firewalls, potentially load balancing, network address translation, we have it up higher, we have it in the software. We have the intelligence up higher. And by up higher, what I mean is that we control it first in the software, and then we decide where we allow it to go back out into the physical network.
We determine where it comes in, and then we determine where it goes out and what it's allowed to do while it's in the software-defined network. So we can do cool things that we haven't been able to do in the past. But in order to do it, we have to understand all of the components that make up NSX. So now that we've discussed what a virtual network is, let's talk about how we build one.
VMware Certified Instructor Bill Ferguson covers the basics of NSX (including NSX components) and techniques for creating a software-defined data center. He shows how to configure a controller cluster, prepare hosts for VXLAN networking, and configure logical switches and distributed routers. Later in the course, Bill configures static and OSPF routing, load balancing, and a simple VPN, as well as high availability with NSX Edge. By the end of the training, viewers should be able to use NSX on top of their existing network resources to improve performance, deploy services, and increase security—without any additional hardware.
- Overview of virtual networks and NSX components
- Configuring controller clusters, logical switches, and distributed routers
- Following packet flow with a DLR
- Understanding Layer 2 bridging
- Configuring static and OSPF routing
- Understanding SNAT and DNAT
- Configuring load balancing
- Configuring high availability on NSX Edge