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VSID or VLAN ID for Hyper-V network virtualization?

Microsoft now offers two options with Hyper-V to isolate VMs on virtual networks. Do you know which option is better for your deployment?

Should I use VSID or VLAN ID for my Hyper-V virtual machines?

Both virtual LAN IDs and virtual subnet IDs can help you configure isolated virtual networks for VMs running on a Hyper-V host, but you will need to choose one or the other because only one can be assigned per VM.

Traditionally, if you wanted to isolate a portion of your VMs, you could configure a separate VLAN domain for a group of VMs, which involves assigning the same VLAN ID to each of these VMs. However, starting with Windows Server 2012, you can also assign VSIDs to VMs, as an alternate method to isolate VMs on a network.

VSID assignment is only available on Windows Server 2012 and later Hyper-V hosts, while VLAN ID is available on Microsoft Windows Server 2012 R2 and previous versions. VSID is only available for use with Hyper-V network virtualization, but offers greater scalability options.

  • Hyper-V supports up to 4,095 VLAN IDs. In other words, you can only configure 4,095 virtual networks on Hyper-V hosts.
  • VSID can support more than 16 million IDs, so you can theoretically create 16 million virtual networks on Windows Server 2012 and later Hyper-V hosts.

VSID helps you run VMs with the same IP scheme. In other words, you can configure two VMs to use the same IP address, as long as these VMs use a different VSID. You assign a VLAN ID on the property page of the VM, which may be an approach many administrators are familiar with. However, you can also use Set-VMNetworkAdapterVlan PowerShell cmdlet to assign a VLAN ID to a VM. This is useful if you want to assign VLAN IDs to multiple VMs.

VSID can only be assigned using the Set-VMNetworkAdapterPowerShell cmdlet. To use VSID, you must also configure other Hyper-V network virtualization components, such as Provider Addresses, VM Networks and routing domain IDs. So, assigning VMs a VSID should be part of a larger Hyper-V network virtualization implementation.

VLAN is a generic approach used by most IT organizations to provide isolation for physical and virtualized workloads. However, with the introduction of VSID, cloud hosting providers now have the option to host up to 16 million virtual networks and provide isolation for different customer VMs.

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