The Internet has resulted in the virtualization of all aspects of our life. Today, our workplaces are virtual, we shop virtually, get virtual education, entertainment is all virtual, and in fact, much of our computing is virtual. The critical enabler for all virtualizations is that the Internet and various computer networking technologies. It seems that computer networking itself has got to be virtualized. Several new standards and technologies are developed for network virtualization.
There are many reasons why we'd like to virtualize resources. The five most typical causes are:
1. Sharing: When help is just too big for a single user, it's best to divide it into multiple virtual pieces, as is the case with today's multi-core processors. Each processor can run multiple virtual machines (VMs), and a particular user often employs each device. An equivalent applies to high-speed links and large-capacity disks. 2. Isolation: Multiple users sharing a resource may not trust one another, so it's essential to provide isolation among users. Users using one virtual component shouldn't be able to monitor the activities or interfere with other activities users.
3. Aggregation: If the resource is too small, it is possible to construct an outsized virtual resource that behaves like an enormous resource. This is the case with storage. An excessive number of cheap unreliable disks can be wont to structure large reliable storage.
4. Dynamics: Often, resource requirements change fast thanks to user mobility. A way to reallocate the resource quickly is required. This is often easier with virtual resources than with physical resources.
5. Simple management: Last but probably the most crucial reason for virtualization is management ease. Virtual devices are easier to manage because they're software-based and expose a consistent interface through standard abstractions.
VIRTUALIZATION IN COMPUTING
Virtualization isn't a replacement concept to computer scientists. Memory was the primary among the pc components to be virtualized. Memory was an expensive a part of the first computers, so virtual memory concepts were developed in the1970s. Study and comparison of various page replacement algorithms was a well-liked research topic then. Today's computers have very sophisticated and multiple levels of caching for memory. Storage virtualization was a natural next step with virtual disks, virtual compact disc (CD)drives, resulting in cloud storage today. Virtualization of desktops resulted in thin clients, eventually resulting in virtualization of servers and cloud computing. Computer networking is the plumbing of computing, and like plumbing altogether beautiful buildings, networking is the key to several of the features offered by new computing architectures. Virtualization in networking is additionally not a replacement concept. Virtual channels in X.25-based telecommunication networks and subsequent networks allow multiple users to share an outsized physical channel. Virtual local area networks(VLANs) enable various corporation departments to share a physical LAN with isolation.
Similarly, virtual private networks (VPNs) allow companies and employees to use public networks with an equivalent security level they enjoy in their networks. However, Several new standards are developed and are being developed. Software-defined networking (SDN) also helps in network virtualization.
A network starts with a network interface card (NIC) within the host, which is connected to a layer 2 (L2) network (Ethernet, WiFi, etc.)segments. Several L2 network segments could also be interconnected via switches (a.k.a. bridges) to make an L2 network, which is one subnet during a layer 3 (L3) network (IPv4 or IPv6). Multiple L3 networks are connected via routers (a.k.a. gateways) to make the web . one data centre may have several L2/L3 networks. Several data centres could also be interconnected via L2/L3 switches. Each of those network components NIC, L2 network, L2 switch, L3 networks, L3 routers, data centres, and therefore the Internet must be virtualized. There are multiple, often competing, standards for virtualization of several of those components. Several new ones are being developed. When a VM moves from one subnet to another, its IP address must change, which complicates routing. Despite all the mobile IP developments, it's significantly more straightforward to manoeuvre systems within one subnet (within one L2 domain) than between subnets. This is often because the IEEE 802 addresses utilized in L2 networks (both Ethernet and WiFi) are system identifiers (not locators) and don't change when a system moves. Therefore, when a network connection spans multiple L2 networks via L3 routers, it's often desirable to make a virtual L2 network that spans the whole network. In a loose sense, several IP networks appear together.