In this section, we will going to discuss the concept of virtualisation in computer networking. The topic will cover – what is virtualizaton in computer networking, what is the need of virtualization, different types of virtualization, its advantages and disadvantages etc.
Before diving into the virtualization fundamental concept, let us try to understand; what is the term virtual means. The dictionary meaning of the word virtual means “something that does not exist physically”. Whereas, in the context of computing technology, virtual is termed as the emulator or the software to make you feel like as if you are working in a real life environment.
Let us understand it with an example. Nowadays, due to pandemic situation, schools, offices are closed down. The students are attending the class sitting at home. The employees of a company are working and attending the meeting sitting at home. But how is this possible ? Virtual classrooms are organised by the schools for the students using communication softwares like Zoom, Google Meet, and many more. Similarly, employees of the companies are interacting with each other through virtual meeting.
Virtualization refers to the technology that makes use of software and application to give access to the physical networking environment in a virtual manner. Let us discuss the topic in detail.
What is Virtualization in Networking?
Virtualization refers to the process of using special softwares on a physical machine to create virtual machines. The physical machine is termed as the host machine and the virtual system is known as the guest machine.
The special software that is installed on top of the physical machine to create virtual machine is called Hypervisor.
By using the virtualization technique, the network resources of the physical machine are made available to the software amd hardware alternatives to the virtual machines. The network resources can be operating systems, servers, application softwares, processors, main memory, storage space and many more.
What is the need of virtualization in networking?
Traditionally, a single physical server may have one operating system, limited main memory, certain storage space, and one or more specific applications running on top of that. The single server can manage a small network with a limited numbers of clients connected to the server. when there is a limited number of clients and then the server alone can handle the client request single handedly upto certain extent. What if the number of clients increase.
Obviously, more numbers of physical server have to be deployed to handle the client request efficiently without overloading. But there are many demerits of deploying separate physical servers.
- The cost of installing separate serve will increase.
- Each server is dedicated for different applications and services like mail server, web server, DNA, DHCP, FTP database server etc. Each separate server may not utilize the resource of server according to their capacity.
- Even the management and administration of all the severs seems to be complex and time consuming.
Thus, the concept of virtualization came into existence to minimize the above issues of deploying dedicated server for a dedicated application. The virtualization technique manages to utilize the capacity of server upto maximum by installing multiple virtual machines on a single physical machine. Thereby, reducing the installation cost of separate servers. Virtualization also simplifies the administration amd management of network with the help of the network management software from a single window.
How does a virtualization work?
Virtualization describes a technology in which an application, guest operating system, data storage is separated from underlying software and hardware.
A thin software layer known as the hypervisor separates the physical machine from the virtual environment. The hypervisor allows to manage the physical resources and shares amongst the virtual machines according to their needs.
Hypervisor plays the major role in administering the virtualization. The hyper visor ia categorized into two types.
Type 1 and Type 2
Type 1 hypervisor directly runs on top of the host machine. Hence they are also called bare-metal hypervisor. They control the hardware and manage the virtual machine. They just work like an independent operating system. The example of Type 1 hypervisor are VMware ESxi, HyperV etc.
Type 2 hypervisor is also called hosted hypervisor or the virtual machine monitor (VMM). They act like an application software installed on top of the conventional operating system like windows, linux, Mac OS. The virtual machines are created and managed by both Virtual machine monitors through the host operating system. The examples of type 2 Hypervisor are VMware Workstaion Player, Oracle Virtual Box, Parallel Desktop for Mac.
Types of Virtualization
The use of virtualization concept in IT industries brings postive transformation such as reduced cost of network resources, higher performance, quick availability, enhanced disaster recovery solution. For efficient implementation of virtualization, we must have a good knowledge of different types of virtualization techniques and their roles in virtualization.
There are five different types of virtualization techniques in networking.
- Desktop Virtualization
- Server Virtualization
- Network Vrtualization
- Application Virtualization
- Storage Virtualization
Letus understand the separately in details.
The desktop virtualization provides multiple desktop environment for the different users through remote server end. The users are allowed to access their files and application using thin clients. The thin client is a machine that has a minimum hardware configuration like cpu and memory. However, files and applications are stored in remote servers. Each user is provided with user id and password for accessing the different desktop environment. The cloud computing makes use of this features abundantly.
This is another type of virtualization technique where multiple virtual servers are allowed to run on a single physical server. This will reduce the cost of installing different physical servers for specific purpose. It helps in virtual migration, reduced cost of installing new virtual server rather than deploying new physical server. It will also help in energy saving.
Each virtual server runs its own operating system and works independently of each other.
The server virtualization is also called as the hardware based virtualization.
The network virtualization is the provision for integration of software and hardware resources as well as the network functionalites over a software driven single administraitve platform for efficient management amd administration of the entire network. The network virtualization emulates the use of virtual switching, virtual routing and forwarding, VLANs and VPNs.
The network virtualization allows creation of virtual tunnels through existing network amd splitting link bandwidth over muliple channels making them independant of each other.
The application virtualization is the process of virtualization that isolates the application or the programs that is to be virtualized, from the underlying operating system on which it is executed. The virtual application itself encapsulates from the distributed package. This application behaves at a runtimes as it is directly interfacing with the original operating system and all the resources are managed by it. However, they can be isolated or sandboxed in varying degrees.
There are three types of application virtualization: Redirection, Layering and virtual environment.
In redirection, the path of application file is changed so that other application cannot recognize it.
In layering, path of the file is not changed. However it is stored in virtual disk and its features are hidden from other application.
In virtual environment, each application is stored as virtual file system and registry subsystem in hyper visor.
In storage virtualization, the data and files of the different virtual machines are stored in a centralised storage system. This centralised storage system manages storage space allocation according to the need of each virtual machine.
The storage system alone creates a dedicated, isolated and a highly secured network called SAN (Storage Area Network). The storage area network consists of enormous volumes of storage space and arranged in array of large numbers of storage media.. like hard diak or tape drives.
The cloud storage is the best example of storage virtualization.
Advantages and Disadvantages of Virtualization in Networking
- Cost saving
- simplifies management
- Guest isolation
- Enhanced backup anad disaster recovery.
- Compromised performance, because hist and the guest share the same amd limited resources.
- increased complexity.
- Risk of failure of host machine leads to disastrous situation.
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