Network Functions Virtualization(NFV) - Part 1

Network Virtualization is getting popular these days and is very trending technology in network space. Before getting into the concept of NFV, let me say something about hypervisors which play an important role in NFV.

What are these hypervisors ?

Hypervisor is a computer software or firmware on which several virtual machines are run.

Hypervisors create an environment for guest operating systems and make them believe that the hardware resources is dedicated to them.  But in reality there will be only one set of hardware resources and all the guest operating systems (so called virtual machines) will be sharing that hardware with the help of hypervisors.

History :

The term hypervisor was first coined by IBM way long back in 1956.IBM wanted to run an additional operating system on Mainframe computers and there were some limitations with the supervisor code to run multiple instances of the operating system. IBM tackled the problem by adding another layer in the architecture on top of supervisor and that became Hypervisor.

The hypervisor installed on the server hardware(host) controls the guest operating system running on the host machine. Its main job is to cater to the needs of the guest operating system with respect to hardware resources, and effectively manage them so that the instances of multiple operating systems do not interrupt one another.

There are 2 types of Hypervisors:-

Type 1 Hypervisor which directly run on the system hardware. This type of hypervisor is also called as bar metal hypervisor.

Type 2 Hypervisor: This runs on operating system of the host. Above Hypervisor the guest operating system will run.