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Figure 2-68:
NVGRE 
Network Controller 
In Windows Server 2016, it is very important to note that this is a new implementation of the network 
virtualization approach. Let’s call it V2. Why is this important? Well, a lot of things have fundamentally 
changed and in V2, being consistent to how network is structured and implemented in Azure was a 
principal goal. Although the common concept remains the same say for network virtualization as we 
generally described earlier, it means some overhauled technology in Windows Server 2016. One of the 
first things worth mentioning before diving into Network Controller and the Software Load Balancer is 
that the Hyper-V extensible switch has also changed; this means that extensibility options which were 
implemented in V1 of network virtualization will not work on V2. V2 implements the Azure Virtual 
Filtering Platform technology to ensure the consistency model across the private and public cloud. 
In this section, we are going to describe Network Controller, which essentially is now the brain of the 
virtualized network solution that we will implement. In large, complex networks with traditional 
networking technology, we would have implemented a central tool to manage these networks. Using 
these traditional tools, we would provide a central point of management so that we can automate 
configuration, maintenance, backup, and troubleshooting of the physical switch environment. In a 
virtualized network environment, this is exactly what Network Controller will do. 
Network Controller can interact with the network and be interacted with through two different APIs 
specifically for each function. The Northbound API (implemented as a REST API) is used to interact 
with Network Controller and monitor the network as well as implement configuration changes. The 
Southbound API is used to interact with network devices and detect service configurations and 
basically understand the network. Using tools such as System Center Operations Manager and System 
Center Virtual Machine Manager, you can manage and monitor your network directly from these 
consoles. 
Because Network Controller is considered the brain, it can manage all of the networking virtualization 
technologies included with Windows Server 2016. The following table gives a breakdown of the areas 
Network Controller can manage and a description of the types of management it can do. 

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CHAPTER 2 | Software-defined datacenter