Create logical switches

How to create logical switches

This article describes how to create logical switches in the System Center - Virtual Machine Manager (VMM) fabric, convert a host virtual switch to a logical switch, and set up virtual switch extensions if you need them.

A logical switch brings virtual switch extensions, port profiles, and port classifications together so that you can configure each network adapter with the settings you need and have consistent settings on network adapters across multiple hosts. You can team multiple network adapters by applying the same logical switch and uplink port profile to them.

Set up virtual switch extensions

You install switch extensions on the VMM server and then include them in a logical switch. There are a few types of switch extensions:

• Monitoring extensions can be used to monitor and report on network traffic, but they can't modify packets.
• Capturing extensions can be used to inspect and sample traffic, but they can't modify packets.
• Filtering extensions can be used to block, modify, or defragment packets. They can also block ports.
• Forwarding extensions can be used to direct traffic by defining destinations, and they can also capture and filter traffic. To avoid conflicts, only one forwarding extension can be active on a logical switch.

You can set up a virtual switch extension manager (network manager) if you want to manage extensions using a vendor management console and the VMM console together.

Set up a virtual switch extension manager

1. Obtain the provider software from your vendor and install the provider on the VMM management server. If you have a cluster, install it on all the nodes.
2. Select Fabric > Home > Show > Fabric Resources > Networking > Switch Extension Managers.
3. In Add Virtual Switch Extension Manager Wizard > General, specify the manufacturer and enter the connection string. For example, myextmanager1.contoso.com:443. The exact syntax is defined by the vendor. Specify the account you want to use to connect to the resource.
4. In Host Groups, specify the host groups for which you want to use the extension manager.
5. In Summary, review settings and select Finish. Check that the extension appears in the Virtual Switch Extension Managers pane.

Set up a logical switch

1. Select Fabric > Networking
2. Right-click Logical Switches, and then select Create Logical Switch.
3. In Create Logical Switch Wizard > Getting Started, review the information.
4. In General,
   • Specify a name
   • Provide a description (optional).
5. In Uplink Mode, select:
   • Embedded Team - if you're using Windows Server 2016 or later
   • Team - if you're using Windows Server 2012 and want to use NIC teaming
   • No Uplink Team - if you're not using any teaming
6. In Settings, select the minimum bandwidth mode. If you've deployed Microsoft network controller, you can specify that it should manage the switch. If you enable this setting, you won't be able to add extensions to the switch.
7. Enable SR-IOV if you need to. SR-IOV enables virtual machines to bypass the switch and directly address the physical network adapter. If you want to enable:
   • Ensure that you've SR-IOV support in the host hardware and firmware, the physical network adapter, and drivers in the management operating system and in the guest operating system.
   • Create a native port profile for virtual network adapters that is SR-IOV enabled.
   • When you configure networking settings on the host (in the host property called Virtual switches), attach the native port profile for virtual network adapters to the virtual switch by using a port classification. You can use the SR-IOV port classification that is provided in VMM, or create your own port classification.
8. In Extensions, if you're using virtual switch extensions, select them and arrange the order. Extensions process network traffic through the switch in the order you specify.

9. In Virtual Port, add one or more port classifications and virtual network adapter port profiles. Every Port Classification must be mapped to a Port Profile.

10. In Uplink, add an uplink port profile, or create a new one. When you add an uplink port profile, it's placed in a list of profiles that are available through that logical switch. However, when you apply the logical switch to a network adapter in a host, the uplink port profile is applied to that network adapter only if you select it from the list of available profiles.

    If Uplink is chosen as Embedded Team (Switch Embedded Team or SET), then the only supported load balancing algorithms are Hyper-V Port and Dynamic. Hyper-V Port is the default load balancing algorithm. If Uplink mode is chosen as Embedded Team, then Hyper-V Port is the recommended load balancing algorithm; Dynamic isn't recommended.

11. In Summary, review the settings and select Finish. Verify; the switch created appears in Logical Switches.

Convert virtual switch to logical switch

If a host in the VMM fabric has a standard virtual switch with or without SET, you can convert it to use as a logical switch.

Compare switch settings

1. Record if NIC Teaming (LBFO) or SET is being used on the host.

2. If you're using NIC teaming on the host, record teaming and load balancing settings by running the PowerShell commandlet Get-NetLbfoTeam.

3. In Hyper-V Manager, right-click the host > Virtual Switch Manager. Select the virtual switch and verify whether Enable single-root I/O virtualization (SR-IOV) is selected. Close Hyper-V Manager.

4. In the VMM console > Fabric > Servers > All Hosts, right-click the host > Properties.

5. In Virtual Switches, note the properties, including logical network and minimum bandwidth mode.

6. In Fabric > Networking > Logical Switches, right-click the logical switch that you want to convert the host configuration to and select Properties.

7. In Logical Switches, record the information:

   • In General, record the uplink mode, whether SR-IOV is enabled, and minimum bandwidth mode.
   • In Extensions, note whether any forwarding extensions have been added to the logical switch.
   • In Virtual port, record the names of the port profiles that are listed. Ensure that you note if one of them has SR-IOV in the name.
   • In Uplinks, record the network sites, whether uplink mode is teamed, the load balancing algorithm, and teaming mode.

8. In Fabric > Networking, select Port Profiles. For any relevant port profiles, select Properties. In Offload Settings, see if Enable Single-root I/O virtualization is checked.

9. Now compare the recorded information that you recorded for the logical switch and port profiles, with the virtual switch information.

10. Review the following table to see whether you can convert the host to use the logical switch.

    Item	Conversion
    SR-IOV	The SR-IOV setting (enabled or disabled) must be the same in the logical switch as it's in the virtual switch. If SR-IOV is enabled, it must be enabled in the logical switch itself, and in at least one virtual network adapter port profile within the logical switch.
    Uplink mode Load balancing algorithm Teaming mode	The Uplink mode setting must match. If the uplink mode is Team, then the Load balancing algorithm and Teaming mode must also match.
    Minimum bandwidth mode	Must match.
    Network sites	The logical switch must be configured for the correct network sites (in the correct logical network) for this host.

11. If the settings in the logical switch don't match as described in the table, you need to find or create a logical switch that does match.

Convert a host to use a logical switch

1. In VMM, select Fabric > Servers > All Hosts. Right-click the host > Properties.
2. On the Virtual Switches tab, select Convert to Logical Switch.
3. Select the logical switch that you want to convert the host to. Then select the uplink port profile to use and select Convert.
4. The Jobs dialog box might appear, depending on your settings. Ensure that the job has a status of Completed and then close the dialog.
5. To verify that the switch was converted, right-click the host, select Properties, and then select the Virtual Switches tab.