chapter lll.pptx
- 1. What is Computer Networking A computer Network is a system that connects numerous independent computers in order to share resources. The integration of computers and other different devices allows users to communicate more easily A computer network consists of various kinds of nodes, servers and networking devices.
- 2. Data Communications When we communicate, we are sharing information. This sharing can be local or remote. Between individuals, local communication usually occurs face to face, while remote communication takes place over distance The term telecommunication means communication at a distance. The word data refers to information presented in whatever form is agreed upon by the parties creating and using the data. Data communications are the exchange of data between two devices via some form of transmission medium such as a wire cable.
- 3. 3/15 Five components of data communication
- 4. Five components of data communication Message :- is information to (Data) be communicated E.g. text, numbers, Audio, Video. Sender :- Device that sends the Data message E.g. Computer , Work-station ,telephone handset television and so on. Receiver:- Device that receive the message E.g. Computer , Work-station ,telephone handset television and so on. Transmission Medium :- Physical Path in which the message travels from sender to Receiver. E.g Twisted Pair, Coaxial Cable, Fiber Optics 4/15
- 5. Five components of data communication Conti… Protocols:- Set of Rules that Govern the data communication. Represent the agreement between Communication. Without Protocol two Device can be connected but not communicate each other E.g. Just person speaks amharic can’t understand a person speak Somali. 5/15
- 6. Four Fundamental Characteristics Delivery :- the system must deliver data to the correct destination. Accuracy:-the system must deliver the data accurately. Timeliness:- The data must deliver data in a timely manner, data delivery late are useless. In case of video, and Audio, timely delivery means delivering date as they produced – this kind of delivering is known as Real-time transition. Jitter, refers the variation of the packets arrival time 6/15 The effectiveness of data communications system depends four fundamental characteristics:
- 7. 7/15 Data flow (simplex, half-duplex, and full-duplex)
- 8. Data Flow Communication between two devices can be simplex, half duplex or full duplex In Simplex mode, the communication is unidirectional, as on a one-way. Only one of the two devices on a link can transmit the other can only receive In half-duplex mode, each station can both transmit and receive but not at the same time. When one device is sending, the other can only receive and vice versa. In full-duplex mode, both stations can transmit and receive simultaneously.
- 9. What are the network criteria that the network must be able to meet?
- 10. Network Criteria A network must be able to meet a certain number of criteria. The most important of these are: performance Reliability Security
- 11. Performance Performance can be measured in many ways including transit time and response time. Transit time is the amount of time required for a message to travel from one device to another. Response time is the elapsed time between an inquiry and a response. The performance of a network depends on a number of factors including the number of users, the type of transmission medium, the capabilities of the connection hardware and the efficiency of the software.
- 12. Reliability In addition to accuracy of delivery, network reliability is measured by the frequency of failure, the time it takes a link to recover from a failure.
- 13. Security Network security issues include protecting data from unauthorized access, protecting data from damage and development, and implementing policies and procedures for recovery from data loss.
- 14. NETWORKS • A network is a set of devices (often referred to as nodes) connected by communication links. A node can be a computer, printer, or any other device capable of sending and/or receiving data generated by other nodes on the network. • For communication to occur, two devices must be connected in some way to the same link at the same time. • There are two possible types of connections: Point-to-Point Multipoint
- 15. What is the difference between Point- to-Point and multipoint connections?
- 16. Types of connections: point-to-point and multipoint
- 17. Point-to-Point and Multipoint A Point-to-Point connection provides a dedicated link between two devices. A multipoint connection is one in which more than two specific devices share a single link.
- 18. Any Question??
- 19. Thanks