What is Error Correction and Detection - peak concepts

Error detection and correction has great practical importance in maintaining data (information) integrity across noisy Communication Networks channels and lessthan- reliable storage media.

Error Correction : Send additional information so incorrect data can be corrected and accepted. Error correction is the additional ability to reconstruct the original, error-free data.

 

There are two basic ways to design the channel code and protocol for an error correcting system :

• Automatic Repeat-Request (ARQ) : The transmitter sends the data and also an error detection code, which the receiver uses to check for errors, and request retransmission of erroneous data. In many cases, the request is implicit; the receiver sends an acknowledgement (ACK) of correctly received data, and the transmitter re-sends anything not acknowledged within a reasonable period of time.

 

• Forward Error Correction (FEC) : The transmitter encodes the data with an error-correcting code (ECC) and sends the coded message. The receiver never sends any messages back to the transmitter. The receiver decodes what it receives into the "most likely" data. The codes are designed so that it would take an "unreasonable" amount of noise to trick the receiver into misinterpreting the data.

 

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What is packet - peak concepts

A packet is the unit of data that is routed between an origin of  computer  network and a destination of computer network on the Internet or any other packet-switched computer network. When any file (e-mail message, HTML file, Graphics Interchange Format file, Uniform Resource Locator request, and so forth) is sent from one place of computer network to another place of computer network on the Internet, the Transmission Control Protocol (TCP) layer of TCP/IP of computer network. 

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Advantages of Peer to Peer Networks - peak concepts

1. Such networks are easy to set up and maintain as each computer manages itself.

2. It eliminates extra cost required in setting up the server.

3. Since each device is master of its own, they an: not dependent on other computers for their operations.

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What is Internet - peak concepts

Internet : A specific Internetworking, consisting of a worldwide interconnection of governmental, academic, public, and private networks based upon the Advanced Research Projects Agency Network (ARPANET) developed by ARPA of the U.S. Department of Defense also home to the World Wide Web (WWW) and referred to as the 'Internet' with a capital 'I' to distinguish it from other generic internetworks. Participants in the Internet, or their service providers, use IP Addresses obtained from address registries that control assignments.

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What is Intranet - peak concepts

Intranet : An intranet is a set of interconnected networks or Internetworking, using the Internet Protocol and uses IP-based tools such as web browsers and ftp tools, that is under the control of a single administrative entity. That administrative entity closes the intranet to the rest of the world, and allows only specific users. Most commonly, an intranet is the internal network of a company or other enterprise. A large intranet will typically have its own web server to provide users with browseable information.

 

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What is Extranet - peak concepts

Extranet : An extranet is a network of internetwork or Internetworking that is limited in scope to a single organisation or entity but which also has limited connections to the networks of one or more other usually, but not necessarily, trusted organizations or entities .Technically, an extranet may also be categorized as a MAN, WAN, or other type of network, although, by definition, an extranet cannot consist of a single LAN; it must have at least one connection with an external network.

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What is Internetworking - peak concepts

Internetworking started as a way to connect disparate types of computer networking technology. Computer network term is used to describe two or more computers that are linked to each other. When two or more computer networks or computer network segments are connected using devices such as a router then it is called as computer internetworking. 

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What is Transaction server - peak concepts

Transaction servers- Clients invoke remote procedures that reside on servers which also contains an SQL database engine. There are procedural statements on the server to execute a group of SQL statements (transactions) which either all succeed or fail as a unit. The applications based on transaction servers are called On-line Transaction Processing (OLTP) and tend to be mission-critical applications which require 1-3 second response time, 100% of the time and require tight controls over the security and integrity of the database. 

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What is Database server - peak concepts

Database servers-In database servers, clients passes SQL (Structured Query Language) requests as messages to the server and the results of the query are returned over the network. The code that processes the SQL request and the data resides on the server allowing it to use its own processing power to find the requested data, rather than pass all the records back to a client and let it find its owndata as was the case for the file server. 
 

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What is file server - peak concepts

File servers. -With a file server, the Computer Network client passes requests for 
computer network files or file records over a computer network to the file server. 

This form of computer network data service requires large bandwidth and can slow a computer network with many users down considerably. Traditional LAN (Local area Network) computing allows users to share resources, such as data files and peripheral devices, by moving them from standalone PCUs onto a Networked File Server (NFS). 

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What is modem - peak concepts

Modem is abbreviation for Modulator – Demodulator. Modems are used for data transfer from one computer network to another computer network through telephone lines. The computer network works in digital mode, while analog technology is used for carrying massages across phone lines.

Modulator converts information from digital mode to analog mode at the transmitting end and demodulator converts the same from analog to digital at receiving end. The process of converting analog signals of one computer network into digital signals of another computer network so they can be processed by a receiving computer is referred to as digitizing.

 

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What is Switching - peak concepts

Switching: Every time in computer network you access the internet or another  computer network outside your immediate location, your messages are sent through a maze of transmission media and connection devices. The mechanism for moving information between different computer network and network segment is called switching in computer network. 

For example: - whenever a telephone called is placed, there are numerous junctions in the communication path that perform this movement of data from one network onto another network.

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What are Network Services - peak concepts

1. Network services are the thing that a network can do. The major networking services are

2. File Services: This includes file transfer, storage, data migration, file update, synchronization and achieving.

3. Printing Services: This service produces shared access to valuable printing devices.

4. Message Services: This service facilitates email, voice mails and coordinate object oriented applications.

5. Application Services: This services allows to centralize high profile applications to increase performance and scalability

6. Database Services: This involves coordination of distributed data and replication. 

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Advantages of Network - peak concepts

The following are the distinct notes in favor of computer network.

 

1. The computers, staff and information can be well managed

2. A network provides the means to exchange data among the computers and to make programs and data available to people

3. It permits the sharing of the resources of the machine

4. Networking also provides the function of back-up.

5. Networking provides a flexible networking environment. Employees can work at home by using through networks ties through networks into the computer at office. 

 

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What is a computer network - peak concepts

A computer network consists of two or more computers that are linked in order to share resources such as printers and CD-ROMs, exchange files, or allow electronic communications. The computers on a computer network may be linked through cables, telephone lines, radio waves, satellites, or infrared light beams.

Computer network can be classified on the basis of following features :

By Scale:Computer networks may be classified according to the scale :

    Local Area Network (LAN)
    Metropolitan Area Network (MAN)
    Wide Area Network (WAN)

By Connection Method: Computer networks can also be classified according to the hardware technology that is used to connect the individual devices in the network such as Optical fibre, Ethernet, Wireless LAN.

 

By Functional Relationship (Network Architectures) : Computer networks may be classified according to the functional relationships which exist between the elements of the network. This classification also called computer architecture. There are two type of network architecture :

• Client-Server
• Peer-to-Peer Architecture

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