Network Virtualization Guide with System Center 2012 Virtual Machine Manager Service Pack 1 by Kristian Nese

imageOne of the most interesting features included with Windows Server 2012 is the Hyper-V Network Virtualization capability. This feature allows you to move your virtual machines from data center to data center, or from data center to cloud service provider hosting environment and keep the IP addressing information that has already been assigned to the virtual machine or a collection of virtual machines that might represent a service.

Virtual machine mobility is a key capability that enables you to really take advantage of the cloud. Without this kind of mobility, you remain stuck in the “stateful” world of the traditional data center. With cloud, you really want to decouple the workload from the underlying network, compute and storage infrastructure that supports it and surface those infrastructure components as abstractions so that the workload only needs to deal with the abstraction and not the actual hardware components themselves. Cloud thus becomes the “HAL” for the data center itself.

While Hyper-V network virtualization is a fantastic feature and enables all sort of scenarios never before possible, it’s not very easy to configure. If you depend on the Windows Server 2012 platform capabilities, you’ll need to be very well versed in PowerShell and PowerShell scripting. While it can be done, it will take some time for you to figure out how to do it. We do have some documentation on how to do that and you can find it in the TechNet Gallery at

But if you really want to do it right with the minimum about of pain, then you’ll want to deploy System Center 2012 Virtual Machine Manager Service Pack 1. Still, you’ll need to know how to configure it in SCVMM. This is where Kristian Nese, a System Center MVP, comes in! He has written an excellent guide to get your started. Here’s the introduction to his article:

image“…What the heck is network virtualization – and why do we need it?

Not everyone needs network virtualization, but the industry itself need a better way to meet the requirements for a secure multi-tenant infrastructure. To isolate tenants from each other without purchasing all the network infrastructure in the world.

As you may be aware of, Windows Server 2012 is truly a cloud OS. It’s more than just a server. It’s the private (and public) cloud enabler and the most important ingredient in your infrastructure to design a multi-tenant infrastructure at low cost, in conjunction with other pieces. Like storage for example, but that’s another story (SMB, Storage Pools/Spaces, resource groups ++).

I have been working a lot with hosters over the last years and a common challenge is a secure and scalable solution for multi-tenancy. First thing that you might think of in relation to network is to use VLAN`s. Fair enough, that`s a wide adopted technology to separate networks, but it is also complex and not suited to scale. When I say scale, I am thinking of big time scale, for those major hosters.

In these days when cloud computing is all over the place, we are expecting our service providers to provision infrastructure, platform and software as a Service quite rapidly, working together with anything else and without making any changes to our environment. Unfortunately this is very challenging and not practically realistic.

One additional challenge to VLAN`s is that when you need to scale your Fabric with new virtualization hosts, storage and networking, you are in some ways limited to one physical location.

VLAN can’t span multiple logical subnets and will therefore restrict the placement of virtual machines. So how can you get a solution that works for your customers – even when they have already existing solutions that they want to move to the cloud?

By using traditional networking and VLAN`s you will have to reassign IP addresses when moving to the cloud, since mostly of the configuration is relying on the IP configuration on those machines. This will include policies, applications, services and everything else that is used for layer 3 network communications. With the limitations of VLAN`s, the physical location will determine the virtual machine`s IP addresses.

This is where Network Virtualization in Windows Server 2012 – Hyper-V comes to the rescue.

It removes the challenges related to IaaS adoption for customers, and will provide the datacenter administrator an easy an effective way to scale their network fabric for virtual machines.

Network Virtualization will let you run several virtual machines – even with the same identical IP assigned, without letting them see each other, which sounds like the solution for multi-tenancy…”

For the rest of the article, which includes detailed configuration information, please see The Network Virtualization Guide with System Center 2012 and Virtual Machine Manager Service Pack 1.


Tom Shinder
Principal Knowledge Engineer, SCD iX Solutions Group
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