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Set up VM networks in SDN using VMM

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This article provides information about how to create VM networks in an SDN using System Center Virtual Machine Manager (VMM).

VM networks are abstract objects that act as an interface to logical networks. In a virtualized network environment, by using the VM networks, you can abstract virtual machines from the underlying logical network.

VMM 2025 and 2022 provide dual stack support for VM networks.

A logical network can have one or more VM networks associated with it based on its isolation settings.

The following two types of isolation settings are supported in SDN fabric:

  • Network virtualization: If a logical network is isolated using network virtualization, you can create multiple VM networks for this logical network. Within a VM network, tenants can use any IP addresses regardless of the IP addresses used on other VM networks. As a service provider, you can host workloads from multiple tenants on a single logical network. Tenants can also configure network connections on these VM networks.

  • No Isolation: If a logical network has no isolation, then only a single VM network can be associated with it. As a service provider, you can host infrastructure workloads using this type of isolation settings.

Note

VLAN isolation is not supported in SDN fabric.

Before you start

Ensure the following:

  • Network controller is deployed in the SDN fabric. Learn more.

  • A logical network with appropriate isolation settings is created and is set to be managed by the Microsoft network controller. Also, create the IP pools for this logical network.

Note

If you want to deploy the VMs with dynamic IP on no isolation network, then IP pools are not required.

  • By default, VMs connected to a VM network with network virtualization isolation setting can't connect to other networks. If you want your VM network to connect to other networks, you need to first deploy SDN SLB and SDN gateway.

Create a VM network (network virtualization)

  1. In the VMM fabric, select VMs and Services > VM Networks > Create VM Network.

  2. In Create VM Network Wizard > Name, enter a name and optional description, and select a logical network that was created with network virtualization isolation settings.

  3. In Isolation, select Isolate using Hyper-V network virtualization, and then select IPv4 for IP address protocols for the VM network. Select Next.

    Screenshot of VM network in sdn.

  4. In VM Subnets, select Add, specify the name and subnets for VM network, and then select Next.

    Note

    You can add multiple subnets.

  5. In Connectivity panel, select the type of connectivity you want to use for this VM network.

    Note

    By default, all virtual machines in a VM network communicate with each other. If you want virtual machines on this VM network to communicate with other networks, configure the following settings in the Connectivity page:

    • Connect to another network through a VPN tunnel: Select this option if you want the virtual machines on this VM network to communicate with other networks over a VPN. To automatically learn routes between the sites connected through the VPN tunnel, select the Enable the border gateway protocol option. Select the VPN gateway device that you want to use and confirm the settings.

      Based on your selection, the VPN Connections and Border Gateway Protocol pages appear. Complete the settings based on the information provided by the VPN admin.

    • Connect directly to an additional logical network: Select this option if you want the virtual machines on this VM network to connect directly to an additional logical network. To enable access to internet resources, select Network Address Translation (NAT) or select Direct Routing to bridge a virtualized IP address space with a physical IP address space.

  6. In Summary, verify the settings and select Finish.

Once the job is successfully completed, you can view the newly created VM network under VMs and Services > VM Networks.

Note

After you create a VM network with network virtualization, ensure that you create an IP Pool for this VM network.

Create a VM network (network virtualization)

  1. In the VMM fabric, select VMs and Services > VM Networks > Create VM Network.

  2. In Create VM Network Wizard > Name, enter a name and optional description, and select a logical network that was created with network virtualization isolation settings.

  3. In Isolation, select Isolate using Hyper-V network virtualization, and then select IPv4 for IP address protocols for the VM network. Select Next.

  4. To enable dual stack support in Isolation, select Isolate using Hyper-V network virtualization, and then select IPv4 and IPv6 for IP address protocols for the VM network. Select Next.

    VM network in sdn

  5. In VM Subnets, select Add, specify the name and subnets for VM network, and then select Next.

    Note

    • You can add multiple subnets.
    • To enable dual stack support, provide both IPv4 subnet and IPv6 subnet separated by a semicolon (;).
    • For VM network with dual stack support, create two static IP pools with both IPv4 and IPv6 address space.

  6. In Connectivity panel, select the type of connectivity you want to use for this VM network.

    Note

    By default, all virtual machines in a VM network communicate with each other. If you want virtual machines on this VM network to communicate with other networks, configure the following settings in the Connectivity page:

    • Connect to another network through a VPN tunnel: Select this option if you want the virtual machines on this VM network to communicate with other networks over a VPN. To automatically learn routes between the sites connected through the VPN tunnel, select the Enable the border gateway protocol option. Select the VPN gateway device that you want to use and confirm the settings.

      Based on your selection, the VPN Connections and Border Gateway Protocol pages appear. Complete the settings based on the information provided by the VPN admin.

    • Connect directly to an additional logical network: Select this option if you want the virtual machines on this VM network to connect directly to an additional logical network. To enable access to internet resources, select Network Address Translation (NAT) or select Direct Routing to bridge a virtualized IP address space with a physical IP address space.

  7. In Summary, verify the settings and select Finish.

Once the job is completed successfully, you can view the newly created VM network under VMs and Services > VM Networks.

Note

After you create a VM network with network virtualization, ensure that you create an IP Pool for this VM network.

Create a VM network (no isolation)

Note

While creating the logical network, if you have chosen the option Create VM network with same name to allow virtual machines to access this logical network directly, then you can skip the following steps.

  1. Select VMs and Services > VM Networks . Create VM Network.
  2. In Create VM Network Wizard > Name, enter a name and optional description. Select a One connected logical network for this VM network. Select Next.
  3. In Summary, verify the settings and select Finish.

Once the job is successfully completed, you can view the newly created VM network under VMs and Services > VM Networks.

Note

If you had created an IP pool on the logical network, the same will be directly available for the VM network.

Next steps

Create an IP pool for a VM network