Virtual network for Hyper-V - Part 1

In this series, I will show you how to connect a virtual network in a Hyper-V environment and how to configure a virtual network to help you achieve your connection goals.

Understanding Hyper-V's internal network connection is the key to achieving high server performance and high resiliency. In this series, I will show you how to connect to a virtual network in a Hyper-V environment and how to configure a virtual network to help you achieve your connectivity goals.

One of the main reasons why many organizations implement virtualization of their data centers is first to reduce hardware costs, in this way they can take advantage of existing server hardware in organize yourself. However, how to make use of the problem is that you understand how to configure it to get the best performance.

With that in mind, we want to show you some in-depth knowledge about virtual networking. How to configure virtual network connectivity will have a big impact on server performance and the overall resilience of the servers it holds.

Before we start, we need to understand that each virtualization product will enable virtual network connectivity in a different way. In this series, we will discuss virtual networking in Hyper-V.

Virtual Network Adapter

The first aspect of the virtual network connection that I want to introduce is the virtual network adapter. To demonstrate, we have installed Hyper-V on the Windows Server 2008 R2 server name. In Hyper-V, the server's primary operating system is known as the parent partition. The parent partition is referred to as the host operating system in Virtual Server and sometimes you still see it as the host operating system, even for Hyper-V.

With that configuration, let's take a look at Figure A. This figure shows the existing network adapters within the main partition of the server.

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Figure A: Hyper-V creates a Virtual Network Adapter

The network adapter on the left side of the window is a physical network adapter, which is connected to a physical Ethernet switch. Before installing Hyper-V, we configured this adapter using an IPv4 address. Then use this network connection to join the server to the domain and download updates from Microsoft.

At first, it seems nothing special about this network adapter. However, everything changed when installing Hyper-V. To see what has changed, look at Figure B. Figure B shows the properties page of this network connection.

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Figure B: Hyper-V has made some significant changes compared to how the physical network adapter is configured within the parent partition.

As mentioned earlier, we used this network adapter when joining the server to the domain and when downloading updates for Windows Server. If you look closely at the image above, you will see that both IPv4 entries (Internet Protocol Version 4 (TCP / IPv4)) and IPv6 (Internet Protocol Version 6 (TCP / IPv6)) are disabled. The Client for Microsoft Networks section is also disabled, along with many other items in the list.

Only one item that is activated is Microsoft Virtual Network Switch Protocol. This protocol is not installed by default. It is only added when you install Hyper-V.

If you look back at Figure A, you will see that the second network adapter is listed as a physical Ethernet adapter and it has been disabled. In fact, we don't do anything with Hyper-V or with a virtual network, but only configure the server to use two physical network adapters, the reasons we will explain later in this series. A week earlier, this adapter stopped working. Since it was not possible to replace the failed adapter, we temporarily disabled it. Therefore, in this article you do not need to care about this adapter.

The network adapter on the right side of Figure A looks at a glance like the other two adapters, but you will see the description of the adapter saying 'Local Area Connection - Virtual Network'. As the name implies, this is a virtual network adapter that was added to the parent partition when installing Hyper-V.

Look at Figure C. Figure C shows the property page for the virtual network adapter of the parent partition. As you can see in the figure, the virtual network adapter is configured as the server's physical network adapter configured before installing Hyper-V. IPv4 and IPv6 protocols are enabled, followed by Client for Microsoft Networks, the QoS Packet Scheduler and File and Printer Sharing for Microsoft Networks.

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Figure C: The parent partition of the virtual network adapter is configured to resemble the physical network adapter configuration before installing Hyper-V

Although the external configuration looks quite similar, the virtual network adapter does not accept the configuration of the physical network adapter. The problem is that before installing Hyper-V, the physical network adapter was configured to use the default configuration. Therefore, when installing Hyper-V, the virtual network adapter also uses this default configuration. However, not all previously selected configurations are in the configuration of the virtual network adapter.

Before installing Hyper-V, we configured the server's physical network adapter using static IPv4 addresses. However, the virtual network adapter did not accept this address. So to be able to use static IPv4 addresses we had to assign an IPv4 address to the virtual network adapter. Also note that if the DHCP server is available, you can also assign a dynamic IP address to the virtual network adapter.

So far we have shown you the configuration of the virtual network adapter and its difference from the physical network adapter in terms of configuration, but we still have not explained much about the virtual network adapter and it does what things

In Hyper-V, the parent partition does not have control over the entire server hardware. Most hardware functions are managed by a low-level component called Hyervisor. Hyervisor will secure hardware resources for each virtual machine and for the server's main operating system.

As I said earlier, Microsoft calls the server's primary operating system the parent partition. Virtual machines exist within child partitions (or sometimes as guest partitions). The problem here is that each operating system resides in its own partition, on a Hypervisor. That said, the parent partition does not directly use a physical network adapter, but instead all network requests are routed through a virtual network adapter, then through a virtual switch, and finally to the physical network adapter. The diagram is clearly shown in Figure D, demonstrating how to work:

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Figure D: The parent partition converts all network requests through the virtual network adapter

Conclude

In this section we hope you have begun to see how the virtual network adapters are used in Hyper-V. In the second part of this series, we will introduce you to the main role of virtual network switching.