Virtual networking enables communication between multiple computers, virtual machines (VMs), virtual servers, or other devices across different office and data center locations. While physical networking connects computers through cabling and other hardware, virtual networking extends these capabilities by using software management to connect computers and servers over the Internet. It uses virtualized versions of traditional network tools, like switches and network adapters, allowing for more efficient routing and easier network configuration changes.
Virtual networking enables devices across many locations to function with the same capabilities as a traditional physical network. This allows for data centers to stretch across different physical locations, and gives network administrators new and more efficient options, like the ability to easily modify the network as needs change, without having to switch out or buy more hardware; greater flexibility in provisioning the network to specific needs and applications; and the capacity to move workloads across the network infrastructure without compromising service, security, and availability.
A virtual network connects virtual machines and devices, no matter their location, using software. In a physical network, layer 2 and 3 functions of the OSI model happen within physical switches and routers. Plus, physical network interface cards (NIC) and network adapters are used to connect computers and servers to the network. Virtual networking shifts these and other activities to software. A software application, called a virtual switch or vSwitch, controls and directs communication between the existing physical network and virtual parts of the network, like virtual machines. And a virtual network adapter allows computers and VMs to connect to a network, including making it possible for all the machines on a local area network (LAN) to connect to a larger network.
In a physical network, LANs are created to connect multiple devices to shared resources, like network storage, usually through Ethernet cables or Wi-Fi. But virtual networking creates the possibility for virtual LANs (VLANs), where the grouping is configured through software. This means that computers connected to different network switches can behave as if they’re all connected to the same one, and, conversely, computers that share cabling can be kept on separate networks, rather than physically connecting machines using cabling equipment and hardware.
Virtual networking delivers more centralized management and simplified network management. Disparate parts of the network can be accessed remotely for needed updates and changes, or even testing, making network management cheaper and easier.
Virtual networking is the foundation for cloud architectures and applications, since it enables the ability to access, connect, secure, and modify cloud resources.
Virtual networking delivers a variety of business benefits, from lowering capital expenditures and maintenance costs to easily segmenting networks. Specifically, a virtual network:
One example of virtual networking is a virtual private network (VPN), which creates a secure connection between one network and another over the Internet. VPNs allow employees to connect to business networks when working remotely or at home, and also are commonly used to get around Internet censorship and prevent browser history to be visible on public Wi-Fi networks.
Another example of virtual networking is a virtual local area network (VLAN). A VLAN is a subgroup of a network, which combines multiple network devices into one grouping, or domain, and partitions it off from the rest. VLANs improve network speed and performance by more efficiently routing traffic across these subgroups or domains. VLANs also allow significantly more control over network devices and traffic. Isolating certain data within a separate VLAN provides additional security benefits, especially to large networks, by making it more difficult for unauthorized monitoring or interference with the network. VLANs also eliminate the need to add new cabling or make big changes to network infrastructure.
A virtual extensible LAN (VXLAN) is another example of virtual networking. Beyond simply dividing a network into subgroups, VXLANs can virtualize an entire network, providing large-scale overly network and segmentation capabilities. VXLANs greatly increase the capacity and scalability of virtual networks—this is especially important without today’s complex cloud architectures.
Network Functions Virtualization