Data Communication and Networking Tutorials and Study Notes

Introduction HILI subcommittee (IEEE802.1) of the IEEE identified the following possible internetworking scenarios. A single LAN Two LANs connected together (LAN-LAN) A LAN connected to Read More »

 Introduction In the early 1970’s there were many data communication networks (also known as Public Networks), which were owned by private companies, organizations and governments Read More »

DATA COMMUNICATION AND NETWORK CONCEPTS Network The collection of interconnected computers is called acomputer network. Two computers are said to be interconnected if they are Read More »

Network Security Concepts: Viruses: Viruses are programs which replicate and attach to other programs in order to corrupt the executable codes. Virus enters the computer Read More »

  The International Standards Organization created a model called the Open Systems Interconnection, which allows diverse systems to communicate.   The seven-layer OSI model provides Read More »

Data must be transformed to electromagnetic signals to be transmitted.   Data can be analog or digital. Analog data are continuous and take continuous values. Read More »

Digital-to-digital conversion involves three techniques: line coding, block coding, and scrambling.   Line coding is the process of converting digital data to a digital signal. Read More »

Digital-to-analog conversion is the process of changing one of the characteristics of an analog signal based on the information in the digital data.   Digital-to-analog Read More »

OPEN SYSTEMS INTER CONNECTION REFERENCE MODEL (OSIRM )   Introduction to OSI Model & its layers The Open Systems Interconnection (OSI) Model was developed by International Read More »

Bandwidth utilization is the use of available bandwidth to achieve specific goals. Efficiency can be achieved by using multiplexing; privacy and antijamming can be achieved Read More »

  A switched network consists of a series of interlinked nodes, called switches. Traditionally’ three methods of switching have been important: circuit switching, packet switching, Read More »

  The telephone, which is referred to as the plain old telephone system (POTS), was originally an analog system. During the last decade, the telephone Read More »

Data can be corrupted during transmission. Some applications require that errors be detected and corrected.   In a single-bit error, only one bit in the Read More »

Data link control deals with the design and procedures for communication between two adjacent nodes: node-to-node communication.   Framing in the data link layer separates Read More »

  Data communications are the transfer of data from one device to another via some form of transmission medium. A data communications system must transmit Read More »

Multiple Access Protocol We can consider the data link layer as two sublayers. The upper sublayer is responsible for data link control, and the lower Read More »

Ethernet is the most widely used local area network protocoL   The IEEE 802.3 Standard defines I-persistent CSMA/CD as the access method for first-generation 10-Mbps Read More »

  The IEEE 802.11 standard for wireless LANs defines two services: basic service set (BSS) and extended service set (ESS).   The access method used Read More »

A repeater is a connecting device that operates in the physical layer of the Internet model. A repeater regenerates a signal, connects segments of a Read More »

Cellular telephony provides communication between two devices. One or both may be mobile.   A cellular service area is divided into cells.   Advanced Mobile Read More »

Synchronous Optical Network (SONET) is a standard developed by ANSI for fiber-optic networks: Synchronous Digital Hierarchy (SDH) is a similar standard developed by ITU-T. SONET Read More »

Virtual-circuit switching is a data link layer technology in which links are shared. A virtual-circuit identifier (VCI) identifies a frame between two switches. Frame Relay Read More »

At the network layer, a global identification system that uniquely identifies every host and router is necessary for delivery of a packet from host to Read More »

IPv4 is an unreliable connectionless protocol responsible for source-to-destination delivery. Packets in the IPv4 layer are called datagrams. A datagram consists of a header (20 Read More »

Delivery of a packet to a host or router requires two levels of addresses: logical and physical. A physical address identifies a host or router Read More »

The delivery of a packet is called direct if the deliverer (host or router) and the destination are on the same network; the delivery of Read More »

In the client/server paradigm, an application program on the local host, called the client, needs services from an application program on the remote host,’ called Read More »

The average data rate, peak data rate, maximum burst size, and effective band width are qualitative values that describe a data flow. A data flow Read More »

IP Security (IPSec) is a collection of protocols designed by the IETF (Internet Engineering Task Force) to provide security for a packet at the network Read More »

The Domain Name System (DNS) is a client/server application that identifies each host on the Internet with a unique user-friendly name. DNS organizes the name Read More »

TELNET is a client/server application that allows a user to log on to a remote machine, giving the user access to the remote system.   Read More »

Lets See some Basic WWW HTTP study notes   The World Wide Web (WWW) is a repository of information linked together from points all over Read More »

The five areas comprising network management are configuration management, fault management, performance management, accounting management, and security management. Configuration management is concerned with the physical Read More »

Audio/video files can be downloaded for future use (streaming stored audio/video) or broadcast to clients over the Internet (streaming live audio/video). The Internet can also Read More »

Cryptography is the science and art of transforming messages to make them secure and immune to attacks. The plaintext is the original message before transformation; Read More »

Cryptography can provide five services. Four of these are related to the message exchange between Alice and Bob. The fifth is related to the entity Read More »

Topology is the pattern of interconnection of nodes in a local area network(LAN). The topology used helps to select the communication medium and the other Read More »

A protocol is the special set of rules that two or more machines on a network follow to communicate with each other. They are the standards that Read More »