" IDEAS CAN BE LIFE CHANGING ": “SHORT NOTES ON DATA COMMUNICATION AND NETWORK”

Monday, July 21, 2014

“SHORT NOTES ON DATA COMMUNICATION AND NETWORK” –By MaddaliSwetha

[This notes definitely utilized for interview preparation time. But the interviewer expects from you only one line answers with more information in less given time.]

1. Uploading is the process of transferring of files your computer to the computer on the internet.

2. WHAT IS A NETWORK TOPOLOGY?

In communication networks, a topology is a usually schematic description of the arrangement of a network, including its nodes and connecting lines. In other words, Oxford Dictionary meaning of topology is the way in which constituent parts are interrelated or arranged. For Instance - "the topology of a computer network"

Thus, there are two ways of defining network geometry: the physical topology and the logical (or signal) topology.

The physical topology of a network is the actual geometric layout of workstations. There are several common physical topologies, as described below and as shown in the illustration.

TOPOLOGY DIAGRAM

In the bus network topology, every workstation is connected to a main cable called the bus. Therefore, in effect, each workstation is directly connected to every other workstation in the network.

In the star network topology, there is a central computer or server to which all the workstations are directly connected. Every workstation is indirectly connected to every other through the central computer.

In the ring network topology, the workstations are connected in a closed loop configuration. Adjacent pairs of workstations are directly connected. Other pairs of workstations are indirectly connected, the data passing through one or more intermediate nodes.

If a Token Ring protocol is used in a star or ring topology, the signal travels in only one direction, carried by a so-called token from node to node.

The mesh network topology employs either of two schemes, called full mesh and partial mesh. In the full mesh topology, each workstation is connected directly to each of the others. In the partial mesh topology, some workstations are connected to all the others, and some are connected only to those other nodes with which they exchange the most data.

The tree network topology uses two or more star networks connected together. The central computers of the star networks are connected to a main bus. Thus, a tree network is a bus network of star networks.

Logical (or signal) topology refers to the nature of the paths the signals follow from node to node. In many instances, the logical topology is the same as the physical topology. But this is not always the case. For example, some networks are physically laid out in a star configuration, but they operate logically as bus or ring networks.

3. The OSI, or Open System Interconnection, model defines a networking framework to implement protocols in seven layers.

The following layers are:

Physical (Layer 1)

Data Link (Layer 2)

Network (Layer 3)

Transport (Layer 4)

Session (Layer 5)

Presentation (Layer 6)

Application (Layer 7)

4. IEEE 802.5 standard is used for Token Ring

Token ring local area network technology is a protocol which resides at the data link layer of the OSI model. It used a special three-byte frame called a token that travels around the ring.

5. The full form LAN is local-Area Network. LAN is a computer network that spans a relatively small area. Most LAN's are confined to a single building or group of buildings; however, one LAN can be connected to other LAN's over any distance via telephone lines and radio waves. A system of LAN's connected in this way is called a wide-area network (WAN).

6. Wide Area Network is also called WAN. WAN is a collection of computers and network resources connected via a network over a geographic area. Wide-Area Networks are commonly connected either through the Internet or special arrangements made with phone companies or other service providers. A WAN is different from a MAN because of the distance between each of the networks. In a WAN, one network may be anywhere from several hundred miles away, to across the globe in a different country.

7. Computer is a device which accepts the data & produces the result.

8. Printer: Machine for printing text or pictures, especially one linked to a computer.

9. Networking cables are used to connect one network device to other network devices or to connect two or more computers to share printer, scanner etc.

10. A network connector is defined as a device that facilitates the connection or the interconnection of computers and other devices to a network.

11. Definition: The term WWW refers to the World Wide Web or simply the Web. The World Wide Web consists of all the public Web sites connected to the Internet worldwide, including the client devices (such as computers and cell phones) that access Web content. The WWW is just one of many applications of the Internet and computer networks.WWW is based on client server.

12. HTTP - the Hypertext Transfer Protocol - provides a standard for Web browsers and servers to communicate. The definition of HTTP is a technical specification of a network protocol that software must implement.

13. URL stands for Uniform Resource Locator. A URL is a formatted text string used by Web browsers, email clients and other software to identify a network resource on the Internet. Network resources are files that can be plain Web pages, other text documents, graphics, or programs.

URL strings consist of three parts (sub strings):

1. Network protocol

2. Host name or address

3. File or resource location

14. The term spam refers to unsolicited commercial advertisements distributed online. Most spam comes to people via email, but spam can also be found in online chat rooms and message boards.

15. The OSI model is divided into seven processes called Layers.

16. Servers are computers that provide resources to other computers connected to a network.

17. Data communications refers to the transmission of this digital data between two or more computers and a computer network or data network is a telecommunications network that allows computers to exchange data. The physical connection between networked computing devices is established using either cable media or wireless media. The best-known computer network is the Internet.

18. Mainframe computers are computers used primarily by corporate and governmental organizations for critical applications, bulk data processing such as census, industry and consumer statistics, enterprise resource planning and transaction processing. A mainframe computer is a big computer.

Mainframe may refer mainframe computer, large and powerful data processing systems.

19. A supercomputer is a computer at the frontline of contemporary processing capacity – particularly speed of calculation which can happen at speeds of nanoseconds. The fastest type of computer. Supercomputers are very expensive and are employed for specialized applications that require immense amounts of calculations.

20. A client is a piece of computer hardware or software that accesses a service made available by a server.

21. A device that forwards data packets along networks. A router is connected to at least two networks and is located at gateways.

22. In networks, a processing location. A node can be a computer or some other device, such as a printer. Every node has a unique network address.

23. An intranet is a computer network that uses Internet Protocol technology to securely share any part of an organization's information or network operating system within that organization. It is the connection of computer networks in a local area.

An extranet is a private network that uses Internet technology and the public telecommunication system to securely share part of a business's information or operations with suppliers, vendors, partners, customers, or other businesses.

24. Hacker: a person who uses computers to gain unauthorized access to data.

25. Website: a location connected to the Internet that maintains one or more web pages.

26. Domain:

(1) A group of computers and devices on a network that are administered as a unit with common rules and procedures. Within the Internet, domains are defined by the IP address. All devices sharing a common part of the IP address are said to be in the same domain.

(2) In database technology, domain refers to the description of an attribute's allowed values. The physical description is a set of values the attribute can have, and the semantic, or logical, description is the meaning of the attribute.

27. The design of the network is called the network: architecture.

28. Transmission: The action or process of transmitting something or the state of being transmitted.

29. BLOG: A Blog (web log) is usually a personal, time – stamped, online journal that appears on a website. It can be periodically updates by the owner, sometimes called blogger. Many sites offer software to create blogs on personal websites.

In Short, Blog is a website containing a writer's or group of writers' own experiences, observations, opinions, etc., and often having images and links to other websites. Such as personal logs or journal entries posted on the web are known as blogs.

Monday, July 21, 2014

“SHORT NOTES ON DATA COMMUNICATION AND NETWORK” –By MaddaliSwetha

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