In the context of System Center Virtual Machine Manager (SCVMM), a logical network refers to a virtual representation of a physical network infrastructure within a virtualization environment. It enables communication between virtual machines (VMs) and the external network, as well as between VMs residing on the same host or different hosts within the virtualized environment.
In this article, we will show you how to create a logical network in Virtual Machine Manager.
Table of Contents
The logical networks in System Center Virtual Machine Manager represent an abstraction of the underlying physical network infrastructure, so your objects must match the physical topology such as the correct IP and VLAN configuration. A network site in a logical network doesn’t have to reflect an actual physical location but rather a specific set of network configurations, thus will help to model the network based on business needs and connectivity properties.
Now after you defined the Logical Network, we have another network component in VMM known as VM Networks.
The Logical Network and VM Network act as a father and child relationship, because the goal of virtualization is to separate and abstract the logical networks from the VMs. This abstraction is achieved through the use of VM networks. When you use VM networks, the Virtual Machines have no idea of the underlying technology (e.g. VLANs, network virtualization) used by the logical network.
Let’s simplify this concept before we move forward.
We have a father and child relationship, the father is effectively the Logical Network, in a normal configuration the father has essentially children, those children are VLANs in the normal way of wording it you have VLAN part of different types of networks.
Now, to deliver those children back to Virtual Machines, we introduced a concept known as a VM Network (Virtual Machine Network), and each VM Network is essentially a new name for that child, so you define the child as a part of a Logical Network as a “Site”, you now take that and you presented to a Virtual Machines as a VM Network, so effectively giving him a life of his own by calling it a VM Network.
Create a Logical Network
Let’s see now how can we create a step-by-step Logical Network…
1) Open the Virtual Machine Manager Console, and click Connect. 2. Select the Fabric workspace. 3. On the navigation pane, expand Networking, and click Logical Networks.
2) In the upper left-hand corner of the ribbon navigation, click Create | Create Logical Network.
3) In the Create Logical Network Wizard window, on the Name page, type Contoso LAN in the Name field.
4) Ensure that the One connected network radio button is selected, check the boxes for Allow new VM networks created on this logical network to use network virtualization, and Create a VM network with the same name to allow virtual machines to access this logical network directly, and then click Next.
5) On the Network Site page, under Network Sites click Add.
6) Contoso LAN_0 populates automatically in the pane. Under Host groups that can use this network site select All Hosts.
7) Under Associated VLANs and IP subnets click Insert row, type the network subnet settings, and then click Next:
- VLAN: 0
- IP subnet: 192.168.1.0/24
8) The Summary page, review the settings and then click Finish.
9) Review the completed jobs in the Jobs window, and then close the window. 12. In the Logical Networks and IP Pools pane, right-click Contoso LAN, and click Create IP Pool.
10) In the Create Static IP Address Pool Wizard, on the Name page, type Contoso LAN IP Pool in the Name field, ensure that the Logical Network selected is Contoso LAN, and then click Next.
11) On the Network Site page, ensure that the Use an existing network site radio button is selected, and then click Next.
12) On the IP address range page, change the Starting IP address to 192.168.1.10 and the Ending IP address to 192.168.1.100, and then click Next. This will give us 91 usable IP addresses.
13) On the Gateway page, click Insert, enter the gateway IP Address 192.168.1.254, and then click Next.
14) On the DNS page, next to DNS server addresses in the order of use, click Insert, and type 192.168.1.1 as the DNS Server address. Next to DNS search suffixes to append (in order), click Insert and type contoso.com, and then click Next.
15) In case you still have a WINS server in your environment :) enter it here or leave the entry blank, and click Next.
16) On the Summary page, review the settings, PowerShell Script, and then click Finish.
17) Last step, review the completed jobs on the Jobs screen as completed successfully, and then close the window. Here you go, we have created a Logical Network in VMM.
That’s it there you have it!
In this article, we showed you how to create a logical network in System Center Virtual Machine Manager (SCVMM).
The logical network acts as a bridge between the physical and virtual layers of the network infrastructure. It provides a way to define network settings, such as IP addressing, subnet masks, gateways, and DNS configurations, for the virtual machines. By abstracting the physical network details, logical networks offer flexibility and scalability in managing network resources within a virtualized environment.
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