SCVMM 2012 R2 – Logical Switches

OK, logical switches are pretty sweet. Like a lot of things, it took me a little while to wrap my head around the concepts and terminology. The SCVMM concept of a logical switch is very similar to VMWare’s Distributed Virtual Switch. It’s all about finding novel ways to map your networking hardware to virtual abstractions, to hopefully make things easier to manage.

This post will cover one of the most basic configurations. Creating a simple logical network which will connect to both your hosts and VM’s.

Step One – Logical Network

This is where you tell SCVMM how you want to present the physical network to the virtual machine hosts.

  1. Open SCVMM Console -> Fabric -> Networking -> Logical Networks.
  2. Create a ‘Logical Network’.
  3.  You’ll see three options. Choose ‘One Connected Network’ and check both boxes, then click ‘Next’.
  4. On the ‘Network Sites’ page, click ‘Add’.
  5. Check the box next to ‘All Hosts’.
  6. Under the section ‘Associated VLANs and IP subnets’, click ‘Insert Row’.
  7. Change the new row’s VLAN to “0” and make the IP Subnet blank, then click ‘Next’.
  8. On the summary page, click ‘Finish’.

By choosing ‘One Connected Network’, we instruct SCVMM that the sites specified in the ‘Network Sites’ page are all part of the same routable network. This is this simplest way to start.

By adding the new associated VLAN “0” with no subnet, we instruct this logical switch to transmit to and from any IP subnet on the default untagged VLAN.

Step Two – Uplink Profile

When we create a logical switch, we need to define physical ports on the VM hosts that will be designated as ‘uplinks’ to this logical switch. To do this, we need to create a ‘Port Profile’ that describes the uplinks.

  1. Open SCVMM Console -> Fabric -> Networking -> Port Profiles
  2. Create a Hyper-V Port Profile.
  3. On the ‘General’ tab, choose ‘Uplink Port Profile’ and click ‘Next’.
  4. On the ‘Network Configuration’ tab, click the checkbox next to your logical network, then click ‘Next’.
  5. On the ‘Summary’ tab, click ‘Finish’.

Notice that you can change the load balancing algorithm on the ‘General’ tab. Lots of fun stuff available there.

Step Three – Logical Switch

Now, we can create the logical switch!

  1. Open SCVMM Console -> Fabric -> Networking -> Logical Switches
  2. Create a logical switch.
  3. On the ‘Uplink’ page, add your uplink profile.
  4. On the ‘Virtual Ports’ page, add the ‘Host Management’ and ‘High Bandwidth’ profiles.

It’s worth looking into the virtual port profiles. You can do some cool stuff like manage the security settings and QoS.

Step Four – Assign the Logical Switch to Hosts

This can get tricky, and you can end up disconnecting your host from the network. I recommend that you shut down all VM’s on the host, and try this on a host where you have physical access in case things don’t work out quite right.

  1. Open SCVMM Console -> VMs and Services -> All Hosts.
  2. Right-click your host and choose ‘Properties’.
  3. Click the ‘Virtual Switches’ page.
  4. Delete the current standard switch, but don’t click ‘Apply’ yet or the host will become unreachable.
  5. Add your new logical switch, but don’t click ‘Apply’ yet or the host will become unreachable.
  6. Click the new logical switch, and then click ‘New virtual network adapter’ with the following settings, then click ‘Apply’.
    name: mgmt
    port classification: Host Management
  7. Wait a few minutes, then right-click the host and choose ‘Refresh’.

Step Five – Assign the Logical Switch to your VM’s

Alright! Now we can finally use the new-fangled virtual switch.

  1. Right-click a VM on the host and choose ‘Properties’ -> ‘Hardware Configuration’ -> ‘Network Adapter’.
  2. Connect your VM’s Network Adapter to the ‘VM Network’ that matches the ‘Logical Network’ name created in Step 1.
  3. Connect your VM to the ‘Logical Switch’ and assign it a port classification (probably ‘High Bandwidth’).

And congrats! You’ve made it through configuring a SCVMM Logical Switch.




One thought on “SCVMM 2012 R2 – Logical Switches

  1. Pingback: SCVMM 2012 R2 – Using Mac Address Pools | windowsmasher

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