WEEK 1-INTRO TO DATA COM and networking.ppt
- 1. INTRODUCTION In today’s world, the communication is deciding the all facts of the growth. Effective, easiest, understandable, timely communications are creating the world’s better growth. The growth of the internet, telecommunication field, communication devices make the people interactive, happily and wealthy. An event happens in place can be communicated to any place in the world. For example, a live sports event happened in France can be viewed by the people sitting in any place in the world. DATA COMMUNICATIONS AND NETWORKS
- 2. DATA COMMUNICATIONS AND NETWORKS INTRODUCTION - Continues The network allows people to communicate information to any people in the world by means of one-to-one, one-to-many or all. In this chapter, we are going to study about the introduction of networks, network hardware, network software and network architecture.
- 3. DATA COMMUNICATIONS AND NETWORKS Data Communication • Data The word ‘data’ refers that representation of information in an understandable form by the two parties who are creating and using it. The Webster dictionary defined data as “information in digital form that can be transmitted or processed”. The data may be in any form such as text, symbols, images, videos, signals and so on.
- 4. DATA COMMUNICATIONS AND NETWORKS Data Communication - Continues • Communication Communication is a referred as exchanging information from one entity to another entity in a meaningful way. The entities may be referred as human being, machines, animals, birds, etc. The communication could be done between the two entities / parties. The meaningful way refers that the meaning of the communication must be understandable between the two entities. The figure 1.1 shows the model for communication between two people.
- 5. Data Comm - Continues • Data Communication “Data communication is process of exchanging data between two devices through a communication medium in a meaningful way”. The devices must be part of the communication system. The communication system is made up of the both hardware equipment and software. To provide the effective communication system, the following four fundamental characteristics must be followed; DATA COMMUNICATIONS AND NETWORKS
- 6. Data Comm - Contiues • 1. Delivery : The data to be communicated must be delivered to the correct destination. • 2. Accuracy : The data should be delivered accurately as it is without any alteration. • 3. Timeliness : The communication system must deliver the data without any delay. • 4. Jitter : In network the data are split into smaller groups (packets) and send them separately. The variation of the arrival between two packets is referred as jitter DATA COMMUNICATIONS AND NETWORKS
- 7. DATA COMMUNICATIONS AND NETWORKS Components of Data Comm Data communication system is made up of five components:
- 8. DATA COMMUNICATIONS AND NETWORKS 1.Data/Message : It is the primary part of the communication system. The information is communicated between the source and destination is called data/message. 2. Source : The source is a device which generates and sends the data to the destination. 3. Destination : It is a device that receives the data. 4. Medium : It acts as carrier to carry the data from the source to the destination. The carrier provides the path through wire or wireless. 5.Protocol : It is set of rules that govern the data communication in a correct manner.
- 9. DATA COMMUNICATIONS AND NETWORKS Mode of Data Flow The data flow defines the flow direction of the data between source and destination. The data flow may be either simplex or half-duplex or full duplex. The figure below shows the three modes of the data flow
- 10. DATA COMMUNICATIONS AND NETWORKS Data FLOW - Continues
- 11. DATA COMMUNICATIONS AND NETWORKS Data Flow- Continues • Simplex : In simplex mode, the direction of the data flow is unidirectional. One of the device can transmit the data and another device can receive at all time. The example is the CPU sends the data to the monitor at all the time. • Half-Duplex : In half-duplex mode, the data can be transmitted on both directions but not at the same time. One device can send and another one can receive at a time. The example is walkie-talkie. The entire medium is used for the one-way transmission.
- 12. DATA COMMUNICATIONS AND NETWORKS Data Flow - Contiunues •• Full-Duplex : In full-duplex mode, the data can be transmitted on both directions at the same time. One device can send and another one can receive at a time. The example is telephone communication. In this, the entire medium is divided for the two-way transmission.
- 13. DATA COMMUNICATIONS AND NETWORKS NETWORKS A network is set of interconnected devices (sometime referred as nodes) which are used to transmit data between them with agreed protocols. The networks are used to connect the people, machines, devices to share the data anywhere in the world. The devices can be computers, printers, mobile phones, servers which are capable of sending and receiving data. The data can be generated by a device.
- 14. DATA COMMUNICATIONS AND NETWORKS Criteria of Network A network must have the following important criteria for effective communication. • Performance The performance of a network is measured by many factors such as transit time, response time. The transit time is amount of time required to travel a message from source to destination. The response time is amount of time required for inquiry and response.
- 15. DATA COMMUNICATIONS AND NETWORKS Criteria of Network - Continues • Throughput and Delay The throughput of the network is measures as amount of data transferred for specified period of time. The high transmission within the specified period of time is called as high throughput network. The delay is measured as time difference between the transit time and actual time taken to transmit. A good network maintains high through and low delay.
- 16. DATA COMMUNICATIONS AND NETWORKS Criteria of Networks - Continues • Reliability The reliability of a network is referred as data delivery should be accurate, less frequency of break in medium, fast recovery of the physical and logical (data) errors. • Security The security of a network is referred as protecting the data from damages and alteration, unauthorized access of medium, devices and data, providing mechanisms for losses and intrusions.
- 17. DATA COMMUNICATIONS AND NETWORKS Types of Connection As we have already known that a network is a two or more devices interconnected through a communication medium. The medium provides the physical pathway between two devices. The connectivity between the devices is classified into point-to-point and multipoint. • point-to-point It provides a direct and dedicated link between two devices (normally source and destination). The entire transmission capacity of the link is shared for these two devices only. For example, link between monitor and computer. • Multipoint A link is shared by many devices and the transmission capacity is shared by all devices connected. For example, a cable TV network or client-server network.
- 18. DATA COMMUNICATIONS AND NETWORKS CONT:
- 19. Protocols and Standards A Protocol is one of the components of a data communications system. Without protocol communication cannot occur. The sending device cannot just send the data and expect the receiving device to receive and further interpret it correctly. When the sender sends a message it may consist of text, number, images, etc. which are converted into bits and grouped into blocks to be transmitted and often certain additional information called control information is also added to help the receiver interpret the data. DATA COMMUNICATIONS AND NETWORKS
- 20. CONT: For successful communication to occur, the sender and receiver must agree upon certain rules called protocol. A Protocol is defined as a set of rules that governs data communications. A protocol defines what is to be communicated, how it is to be communicated and when it is to be communicated. DATA COMMUNICATIONS AND NETWORKS
- 21. Elements of Protocol There are three key elements of a protocol: A.Syntax It means the structure or format of the data. It is the arrangement of data in a particular order. B.Semantics It tells the meaning of each section of bits and indicates the interpretation of each section. It also tells what action/decision is to be taken based on the interpretation. C.Timing It tells the sender about the readiness of the receiver to receive the data It tells the sender at what rate the data should be sent to the receiver to avoid overwhelming the receiver. DATA COMMUNICATIONS AND NETWORKS
- 22. Standards are necessary in networking to ensure interconnectivity and interoperability between various networking hardware and software components. Without standards we would have proprietary products creating isolated islands of users which cannot interconnect. Concept of Standard Standards provide guidelines to product manufacturers and vendors to ensure national and international interconnectivity. Data communications standards are classified into two categories: DATA COMMUNICATIONS AND NETWORKS Standards
- 23. • 1. De facto Standard • These are the standards that have been traditionally used and mean by fact or by convention • These standards are not approved by any organized body but are adopted by widespread use. • 2. De jure standard • It means by law or by regulation. • These standards are legislated and approved by an body that is officially recognized. DATA COMMUNICATIONS AND NETWORKS
- 24. Siandard Organizations • Standards are created by standards creation committees, forums, and government regulatory agencies. • Examples of Standard Creation Committees : • 1. International Organization for Standardization(ISO) • 2. International Telecommunications Union – Telecommunications Standard (ITU-T) • 3. American National Standards Institute (ANSI) • 4. Institute of Electrical & Electronics Engineers (IEEE) • 5. Electronic Industries Associates (EIA) DATA COMMUNICATIONS AND NETWORKS
- 25. END OF LECTURE THANK YOU!!!! DATA COMMUNICATIONS AND NETWORKS