Network virtualization

In computing, Network Virtualization is the process of combining hardware and software network resources and network functionality into a single, software-based administrative entity, a virtual network. Network virtualization involves platform virtualization, often combined with resource virtualization.

Network virtualization is categorized as either
1. External, combining many networks, or parts of networks, into a virtual unit,
2. Internal, providing network-like functionality to the software containers on a single system.
Whether virtualization is internal or external depends on the implementation provided by vendors that support the technology.

Components of a virtual network
Various equipment and software vendors offer network virtualization by combining any of the following:

• Network hardware, such as switches and network adapters, also known as network interface cards (NICs)
• Networks, such as virtual LANs (VLANs) and containers such as virtual machines (VMs) and Solaris Containers
• Network storage devices
• Network media, such as Ethernet and Fibre Channel

Benefits
Virtualization is thought as a means to overcome the weaknesses of the current Internet. Major
router vendors have already started to support virtual routers and programmability to run user defined protocols. Currently, up to 255 virtual routers can be configured on the physical interface of a single router by using Cisco’s Virtual Router Redundancy Protocol.
In a virtualization-enabled networking infrastructure, a number of diverse VNs(Virtual networks) will be sharing resources offered by an IP-network, such as the Internet, commonly referred to as Substrate Network (SN). These VNs can be constructed through the deployment of virtual routers and virtual links. Moreover, an important requirement for such infrastructures may also be a support to pluralism. It will seek to introduce virtualization as an architectural attribute of the Internet, which will enable continuous embedding of innovative technologies in the Internet. Such approaches will act as protection against ossification of the Internet.
One of the most important issues in network virtualization is an efficient utilization of SN resources. It will help to improve the resource utilization as well as avoiding congestion in the SN.

Risks
1. It may lead to high cost, if the load on the server less.
2. It involves higher complexity.
3. There is increased overhead.