DEFINITION
Network virtualization (NV) refers to abstracting network resources traditionally delivered in hardware to software. NV can combine multiple physical networks to one virtual, software-based network, or it can divide one physical network into separate, independent virtual networks.
Network virtualization is also a method of combining the available resources in a network to consolidate multiple physical networks, divide a network into segments or create software networks between virtual machines (VMs).
Network virtualization makes it possible to programmatically create, provision, and manage networks all in software, using the underlying physical network as a simple packet‐ forwarding backplane. Network and security services in software are dis-tributed to hypervisors and “attached” to individual virtual machines (VMs) in accordance with networking and security policies defined for each connected application. When a VM is moved to another host, its networking and security services move with it. And when new VMs are created to scale an appli-cation, the necessary policies are dynamically applied to those VMs as well.
Types of network virtualization
Virtual networks exist in two forms; internal and external. Both of these terms refer to inside or outside the server. Eternal virtualization will use tools such as switches, adapters or a network to combine one or more networks into virtual units. Internal virtualization refers to using network-like functionality in software containers on a single network server. Internal software allows VMs to exchange data on a host without using an external network.
HOW NETWORK VIRTUALIZATION WORKS
Network virtualization works by combining the available resources in a network and splitting up the available bandwidth into channels, each of which is independent from the others and each of which can be assigned (or reassigned) to a particular server or device in real time. Each channel is independently secured. Every subscriber has shared access to all the resources on the network from a single computer.
Network virtualization is intended to improve productivity, efficiency and job satisfaction of the administrator by performing many of these tasks automatically, thereby disguising the true complexity of the network. Files, images, programs and folders can be centrally managed from a single physical site. Storage media such as hard drives and tape drives can be easily added or reassigned. Storage space can be shared or reallocated among the servers.
Advantages and disadvantages
The use of network virtualization does have its upsides and downsides, including:
Advantages:
- More productive IT environments (i.e., efficient scaling).
- Improved security and recovery times.
- Faster in application delivery.
- More efficient networks.
- Reduced overall costs.
Disadvantages:
- Increased upfront costs (investing in virtualization software).
- Need to license software.
- There may be a learning curve if IT managers are not experienced.
- Not every application and server will work in a virtualized environment.
- Availability can be an issue if an organization can’t connect to their virtualized data.
