This is often achieved via networks of sending and receiving equipment, wires and satellite links. The technologies involved in communication tend to be complex. You certainly don't need to understand them for your ICT course.
However, there are aspects of digital communications that you needs to be aware of. These relate primarily to the types of network and the ways of connecting to the Internet. Let's look at these two briefly further revision notes provide much more detail to support your study. Internal networks Usually referred to as a local area network LAN , this involves linking a number of hardware items input and output devices plus computer processing together within an office or building.
The aim of a LAN is to be able to share hardware facilities such as printers or scanners, software applications and data. This type of network is invaluable in the office environment where colleagues need to have access to common data or programmes.
External networks Often you need to communicate with someone outside your internal network, in this case you will need to be part of a Wide Area Network WAN. The Internet is the ultimate WAN - it is a vast network of networks. Moreover, as information technology protocols, applications, utilities and services are constantly changing, nothing in these guidelines restricts the authority of the relevant offices from initiating new rules or guidelines as circumstances dictate or as technology evolves.
Whether or not an amount of personal use would be considered reasonable would depend on the particular circumstances and the applicable laws and policies. Users of University ICT are required to abide by all applicable laws and policies in addition to these guidelines.
Reasonable personal use does not include in any circumstances the visiting of pornographic websites, the storage or distribution of pornographic material, or the accessing, storage or distribution of unlawful or otherwise inappropriate within the meaning of the guidelines information. Digital Divide: The technological gap between countries that have fully exploited ICT and those that have not. E-Commerce Electronic Commerce: Business activities involving consumers, manufacturers, suppliers, service providers and intermediaries using computer networks such as the Internet.
Global Information Infrastructure GII : The components making up a wide area network arising from multiple heterogeneous networks, which facilitate multidimensional communication among different nations, business and organisations. Information and Communication Technologies ICT : Is a generic term used to express the convergence of information technology, broadcasting and communications.
One prominent example is the Internet. Information Society IS : A country or region where information technology has been fully exploited and is part of everyday life as an enabler of information sharing, communication and diffusion. Information Technology IT : Embraces the use of computers, telecommunications and office systems technologies for the collection, processing, storing, packaging and dissemination of information.
Knowledge Based Economy KBE : A country or region where ICT is extensively used to enhance knowledge so that higher human capital brings further improvement to the economy. Most LANs are confined to a single building or group of buildings. Teledensity: The number of telephones per people in a region.
Click here to sign up. Download Free PDF. IJAR Indexing. A short summary of this paper. Download Download PDF. Translate PDF. Rajesh Kumar1, Vivek Kumar Vaidya2. Polytechnic College, Ujjain M. Polytechnic College, Burhanpur M. This suite is a combination of Received: 12 April Final Accepted: 19 May protocols which encompasses a number of different protocols for different Published Online: June purpose and need.
In contrast with the OSI model, this model of protocols contains less layers. There are several protocols which work for users in Application Layer. Application layer protocols can be broadly divided into two categories. All rights reserved. Introduction:- An application layer is an abstraction layer that specifies the shared protocols and interface methods used by hosts in a communications network. Although both models use the same term for their respective highest level layer, the detailed definitions and purposes are different.
The application layer only standardizes communication and depends upon the underlying transport layer protocols to establish host-to-host data transfer channels and manage the data exchange in a client-server or peer-to-peer networking model. The OSI model defines the application layer as the user interface responsible for displaying received information to the user.
In contrast, the Internet Protocol model does not concern itself with such detail. OSI specifies a strict modular separation of functionality at these layers and provides protocol implementations for each layer. This suite is a combination of protocols which encompasses a number of different protocols for different purpose and need. This protocol suite has its own reference model which it follows over the internet.
This model is indifferent to the actual hardware implementation, i. This is why this model can be implemented on almost all underlying technologies.
Transport and Internet layers correspond to the same peer layers. Hypertext is structured text that uses logical links hyperlinks between nodes containing text. HTTP is the protocol to exchange or transfer hypertext. HTTP functions as a request—response protocol in the client—server computing model. A web browser, for example, may be the client and an application running on a computer hosting a web site may be the server. The client submits an HTTP request message to the server.
The server, which provides resources such as HTML files and other content, or performs other functions on behalf of the client, returns a response message to the client. The response contains completion status information about the request and may also contain requested content in its message body. A web browser is an example of a user agent UA. Other types of user agent include the indexing software used by search providers web crawlers ,voice browsers, mobile apps, and other software that accesses, consumes, or displays web content.
HTTP is designed to permit intermediate network elements to improve or enable communications between clients and servers. High-traffic websites often benefit from web cache servers that deliver content on behalf of upstream servers to improve response time. HTTP proxy servers at private network boundaries can facilitate communication for clients without a globally routable address, by relaying messages with external servers. Its definition presumes an underlying and reliable transport layer protocol,[2] and Transmission Control Protocol TCP is commonly used.
Hypertext is well organized documentation system which uses hyperlinks to link the pages in the text documents.
HTTP works on client server model. When a user wants to access any HTTP page on the internet, the client machine at user end initiates a TCP connection to server on port When the server accepts the client request, the client is authorized to access web pages. To access the web pages, a client normally uses web browsers, who are responsible for initiating, maintaining, and closing TCP connections. HTTP is a stateless protocol, which means the Server maintains no information about earlier requests by clients.
HTTP versions:- 1. HTTP 1. At most one object can be sent over a single TCP connection. In this version, multiple objects can be sent over a single TCP connection. It uses UDP protocol for transport layer communication. DNS uses hierarchical domain based naming scheme. The Domain Name System DNS is a hierarchical decentralized naming system for computers, services, or any resource connected to the Internet or a private network.
It associates various information with domain names assigned to each of the participating entities. Most prominently, it translates more readily memorized domain names to the numerical IP addresses needed for the purpose of locating and identifying computer services and devices with the underlying network protocols.
By providing a worldwide, distributed directory service, the Domain Name System is an essential component of the functionality of the Internet. The Domain Name System delegates the responsibility of assigning domain names and mapping those names to Internet resources by designating authoritative name servers for each domain. Network administrators may delegate authority over sub-domains of their allocated name space to other name servers. This mechanism provides distributed and fault tolerant service and was designed to avoid a single large central database.
The Domain Name System also specifies the technical functionality of the database service which is at its core. Historically, other directory services preceding DNS were not scalable to large or global directories as they were originally based on text files, prominently the HOSTS. TXT resolver. The Domain Name System has been in use since the s. Internet name servers and a communication protocol implement the Domain Name System. Although not intended to be a general purpose database, DNS can store records for other types of data for either automatic lookups, such as DNSSEC records, or for human queries such as responsible person RP records.
As a general purpose database, the DNS has also been used in combatingunsolicited email spam by storing a real-time blackhole list. The DNS database is traditionally stored in a structured zone file. Structure:- Domain Name Space:- The domain name space consists of a tree data structure. Each node or leaf in the tree has a label and zero or more resource records RR , which hold information associated with the domain name.
The domain name itself consists of the label, possibly concatenated with the name of its parent node on the right, separated by a dot. A DNS zone may consist of only one domain, or may consist of many domains and sub-domains, depending on the administrative choices of the zone manager.
DNS can also be partitioned according to class; the separate classes can be thought of as an array of parallel namespace trees. Authority over the new zone is said to be delegated to a designated name server. The parent zone ceases to be authoritative for the new zone.
A1: A computer network is a group of computers linked to each other that enables the computer to communicate with another computer and share their resources, data, and applications. It is used to connect two or more personal computers through a communication medium such as coaxial cable, twisted pair, etc.
LAN is not very costly as it is built with inexpensive hardware such as network adapters, hubs and ethernet cables. The data in Local Area Network will be transferred at an extremely faster rate. LAN provides higher security. It is a network arranged within a range of 10 meters, typically within an individual person.
PAN is used for connecting the computer devices of personal use. Personal Area Network idea was bought by Thomas Zimmerman who was a research scientist. It covers an area of 30 feet.
Personal computer devices that are used to develop the personal area network are the mobile phones, laptop, play stations and media players.
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