Set up VM networks in the VMM fabric

This article describes how to create VM networks based on System Center Virtual Machine Manager (VMM) logical networks.

In a virtualized network environment, we want to abstract virtual machines from the underlying logical network. VM networks help you do this. VM networks are abstract objects that act as an interface to logical networks.

• A logical network can have one or more associated VM networks.

• If a logical network isn't isolated, then a single VM network will be associated with it.

• If a logical network is isolated, then multiple VM networks can be associated with it. These multiple VM networks allow us to use networks for different purposes. For example, as a provider you might want to host workload for multiple tenants on a single logical network, using a separate VM network for each tenant. The type of VM network you set up depends on the isolation settings for the logical network:

  • Network virtualization: If the logical network is isolated using network virtualization, you can create multiple VM networks for a logical network. Within a VM network, tenants can use any IP addresses they want for their VMs regardless of the IP addresses used on other VM networks. Tenants can also configure some network settings.
  • VLAN: If the logical network is isolated using VLAN or PVLAN, you'll create on VM network for each network site and VLAN in the logical network.
  • No isolation: If the logical network is configured without isolation, you'll create a single VM network linked to a logical network.

• In some circumstances, you'll need to create a static IP address pool on the VM network after you've created it. Learn more.
• By default, machines within a specific VM network can connect to each other. If your VM network will connect to other networks, you can configure it with a gateway (network service). If you want to add a gateway to the VM network, you'll need to create it. Learn more.

1. Select VMs and Services > VM Networks > Home > Create > Create VM Network.

2. In Create VM Network Wizard > Name, enter a name and description and select a logical network on which to base the VM network.

3. In Isolation, select Isolate using Hyper-V network virtualization and verify the IP address protocols.

4. In VM Subnets, select Add and specify subnets for the VM network using CIDR notation. You can add multiple subnets.

5. In Connectivity, if you see the message No network service, it specifies a gateway has been added to VMM and you can select Next. If you don't see the message, specify the gateway (network service) options:

   • No connectivity: Leave all checkboxes cleared if the virtual machines on this VM network will communicate only with other virtual machines on this VM network. You can also leave clear if you plan to configure the gateway later.
   • Connect to another network through a VPN tunnel: Select this option if the virtual machines on this VM network will communicate with other networks over VPN. If the device will use the Border Gateway Protocol, enable this protocol. Select the VPN gateway device that you want to use. Confirm the settings. If the VPN Connections or Border Gateway Protocol pages appear, complete the settings based on information from the VPN admin. If you selected the checkbox for Border Gateway Protocol, the Border Gateway Protocol page also appears.
   • Connect directly to an additional logical network: Select this option if the virtual machines on this VM network will communicate with other networks in this data center. Select either direct routing or NAT. Select the gateway device you want to use and confirm the settings.

6. In Summary, verify settings and select Finish. Verify the network in VM Networks and IP Pools.

1. Select VMs and Services > VM Networks > Home > Create > Create VM Network.

2. In Create VM Network Wizard > Name, enter a name and description and select a logical network on which to base the VM network.

3. In Isolation Options:

   • Select Automatic if you want VMM to automatically configure the isolation settings for the VM network. VMM will select a network site and subnet VLAN based on those available in the logical network.
   • Select Specify a VLAN to configure isolation manually.

   Note

   • Tenant administrators can only select the Automatic option.

4. In Summary, verify settings and select Finish. Verify the network in VM Networks and IP Pools.

1. Select VMs and Services > VM Networks > Home > Create > Create VM Network.
2. In Create VM Network Wizard > Name, enter a name and description and select a logical network on which to base the VM network.
3. In VM Networks and IP Pools, check for a VM network with the same name as the logical network you want to give direct access to. If one exists, it probably indicates that the VM network was created automatically when you created the logical network. You can check whether the VM network provides direct access by selecting its properties. If Name and Access are the only tabs, it provides direct access.
4. If there's no existing VM network, select Home > Create > Create VM Network.
5. In Summary, verify settings and select Finish. Verify the network in VM Networks and IP Pools.