A Computer Network is a system that interconnects two or more computing devices and peripherals that are transmitting and sharing information and communicate with one another. Computing devices include everything from a mobile phone to a server. These devices are connected using physical wires such as fiber optics, but they can also be wireless. A Computer Network configuration consists of data processing devices, software, and transmission media that are linked for information interchange. It allows computers to collaborate, transfer data, and access shared information - such as files, emails, and printers - from one device to another.
The first working network, called ARPANET, was created in the late 1960s and was funded by the U.S. Department of defence.
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| Source Google |
Types of Computer Networks
Computer Networks are often classified by size, distance covered, or structure. The following are the types of Computer Network:
1. Personal Area Network (PAN):
A Personal Area Network (PAN) is the most basic type of network. It connects electronic devices within a user's immediate area with devices such as wireless modems, a couple of computers, mobile phones, printers, and more. The size of a PAN ranges from a few centimeters to a few meters, limited to a single individual within a specific building.
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| Source Google |
2. Local Area Network (LAN):
A local area network (LAN) connects personal computers, printers, and other computer resources together within a building or campus. It is using a limited area such as a residence, school, laboratory, university campus or office building. This type of network is usually capable of achieving high data transfer rate (up to 10 Gbps!) at low cost.
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| Source Google |
3. Metropolitan Area Network (MAN):
A metropolitan Area Network is a network that is larger than a LAN Smaller than a WAN. It is called Metropolitan since it normally covers the area of a city or metropolitan area, which could be a single large city, multiple cities and towns, or any given large area with multiple buildings.
4. Wide Area Network (WAN):
A Wide Area Network (WAN) is a physical or logical network that provides data communications to a larger number of independent users than are typically served by a local area network (LAN) and that is usually spread over a larger geographic area. A WAN includes all networks and larger than a MAN. A WAN covers a large geographical area, it not restricted to a geographical location. The technology is high speed and relatively expensive. The Internet is an example of world largest WAN.
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| Source Google |
Network Software
Network software is defined as a wide range of software that streamlines the operations, design, monitoring, and implementation of computer networks.
Networking software—along with the software-defined networks (SDNs) it creates—helps engineers respond to those challenges by enabling the creation of intent-based networks (IBNs).
IBNs reduce IT workload and deployment time, make more-efficient use of resources, and enhance agility. They deliver those benefits by automatically translating business objectives into custom network configurations.
Networking Model
The 802 project of the Institute of Electrical and Electronics Engineer (IEEE) has produced a set of standards for LAN architectures, giving vendors guidance for producing LAN products and users a choice of standardized local area networks with certain degree of interconnectivity.
The Open Systems Interconnection (OSI) model is a conceptual framework that divides network communications functions into seven layers. Each layer in the OSI reference Model has a name, numbers and specific protocols that provide specific functions and define services.
Application Layer: The Application Layer gives the user access to all the lower OSI functions. The purpose of the Application Layer is to support semantic exchanges between applications existing in open system.
Presentation Layer: The Presentation Layer is connected with the representation of user of system data.
Session Layer: The Session Layer provides mechanisms for organising and structuring Interaction between applications and devices.
Transport Layer: The Transport Layer provides transport and reliable end-to-end data transfer, relying on lower functions for handling the peculiarities of the actual transfer.
Network Layer: The Network Layer establish connections between networks. The standard also includes procedures for the operational control of inter-network communications and for the routing of information through multiple network.
Data Link Layer: The Data Link Layer provides the functions and protocols to transfer data between network entities and to detect errors that may occur in the physical layer.
Physical Layer: The Physical layer is responsible for physically transmitting the data over the communications link. The physical layer sends data bits from one device to another device. The physical Layer defines the types of encoding i.e. 0 and 1.
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| 7 Layer OSI reference Model |
Network Topology
A Network Topology is a design layout where the physical and logical arrangement of nodes are connecting in a network. There is total 8 types of Network Topology. They are:
Point to Point Topology:
Point to Point is a simple topology that directly links two nodes and reserves the entire bandwidth of the connection for them to communicate with one another.
Bus Topology:
In a Bus Topology, all the nodes are linked using a single cable with a terminator on both ends.
Ring Topology:
The Ring Topology has no endpoint or terminators. The layout is a continuous loop of cable to which the network nodes are attached. Such network topology is used in smaller networks, like those in schools.
Star Topology:
In a Star Topology, all nodes are connected to a central hub using a communication link. Each node needs a separate wire to establish a point-to-point connection with the hub, which functions as a server to control and manage the entire network. In this topology a single wire segments radiate from the hub like a Star.
In a Tree Topology, nodes are arranged in a configuration that resembles a tree’s leaves, branches, and trunk. Endpoints, or ‘leaves,’ are connected to mid-level nodes or ‘branches’ linked to the tree’s ‘trunk.’ The trunk is the backbone connection that links multiple mid-level nodes.
In a Mesh Topology, all the nodes are interconnected and can send and receive their data and relay data from other nodes. In this topology involves some wiring overhead since every network station is directly connected to all the other network station.
Hybrid Topology:
A Hybrid Topology is a type of network topology that uses two or more differing network topologies. These topologies can include a mix of bus topology, mesh topology, ring topology, star topology, and tree topology.
Cellular Topology :
A Cellular Topology combines wireless point-to point and multiple straggles to divide a geographical area in cells. Each cell represents the portion of the total network area in which a specific connection operates. Devices within the cell communicate with a central station or hub. Hubs are interconnected to rout data across the network and p[provide the complete network infrastructure.
