This design implements software-defined networking by using VMware NSX™ for vSphere®. By using NSX for vSphere, virtualization delivers for networking what it has already delivered for compute and storage.
In much the same way that server virtualization programmatically creates, snapshots, deletes, and restores software-based virtual machines (VMs), NSX network virtualization programmatically creates, snapshots, deletes, and restores software-based virtual networks. The result is a transformative approach to networking that not only enables data center managers to achieve orders of magnitude better agility and economics, but also supports a vastly simplified operational model for the underlying physical network. NSX for vSphere is a nondisruptive solution because it can be deployed on any IP network, including existing traditional networking models and next-generation fabric architectures, from any vendor.
When administrators provision workloads, network management is one of the most time-consuming tasks. Most of the time spent provisioning networks is consumed configuring individual components in the physical infrastructure and verifying that network changes do not affect other devices that are using the same networking infrastructure.
The need to pre-provision and configure networks is a major constraint to cloud deployments where speed, agility, and flexibility are critical requirements. Pre-provisioned physical networks can allow for the rapid creation of virtual networks and faster deployment times of workloads utilizing the virtual network. As long as the physical network that you need is already available on the ESXi host where the workload is to be deployed, this works well. However, if the network is not available on a given ESXi host, you must find an ESXi host with the available network and spare capacity to run your workload in your environment.
To get around this bottleneck, you decouple virtual networks from their physical counterparts. Decoupling, in turn, requires that you can programmatically recreate all physical networking attributes that are required by workloads in the virtualized environment. Because network virtualization supports the creation of virtual networks without modification of the physical network infrastructure, it allows more rapid network provisioning.