Data Communications and Computer Networks
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This document provides an overview of data communications and computer networks. It discusses the basic elements of a communication system including senders, receivers, and transmission media. It then describes different types of transmission media such as twisted pair wire, coaxial cable, microwave systems, and optical fibers. The document also covers digital and analog data transmission, network topologies including star, ring, bus and hybrid networks. It defines local and wide area networks and describes some common networking devices like network interface cards.
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Data Communications and Computer Networks
- 1. Data Communications and Computer Networks
- 2. Learning Objectives In • • this chapter you will learn about: Basic elements of a communication system Techniques, channels, and devices used to transmit data between distant locations Types of computer networks Communication protocols and their use in computer networks Internetworking tools and their use in building large computer networks • • • •
- 3. Basic Elements Of a communication system Medium Carries the message Receives the massage Creates and sends a massage ReceiverSender (source)
- 4. Data Transmission Media The most commonly used ones Twisted-pair wire (UTP cable) Coaxial cable Microwave system are: • • • • • Communications satellite Optical fibers
- 6. Coaxial Cable Central copper wire PVC insulation Copper mesh Outer PVC shield
- 7. Digital and Analog Data Transmission • Analog signal: Transmitted power varies over a continuous range. Example: sound, light, and radio waves • Digital signal: Sequence of voltage pulses represented in binary form • Computer telephone generated data signal is digital, whereas lines carry analog signals
- 8. Digital and Analog Data Transmission (Continued from previous slide) • When digital data is to be sent over an analog facility, digital signals • Conversion of modulation • Conversion of demodulation must be converted to analog form digital signal to analog form is known as analog signal to digital form is known as • Digital transmission of data is preferred over analog transmission transmission of data due to lower cost, higher speeds, and lower error rate
- 9. Analog and Digital Signals Voltage +v t0 1/f 2/f -v (a) Analog signal v 1 1 1 1 0 t (b) Digital signal 0 0 0
- 10. Network Topologies • Term network topology refers to the way in which the nodes of a network are linked together • Although number network topologies four major ones are: • Star network • Ring network • Completely connected network are possible, • Multi-access bus network
- 12. Ring Network
- 14. Multi-Access Bus Network Computers (nodes) Single communication line shared by all nodes
- 16. Network Types • Networks are broadly classified into two types: Local Area Network (LAN) and Wide Area Network (WAN) • Local Area Network (LAN) as compared to WAN: • Limited to a small geographic coverage • Has much higher data transmission rate • Experiences fewer data transmission errors • Has lower data communication cost • Typically owned by a single organization • Networks that share some of the characteristics of both LANs and WANs are referred to as Metropolitan Area Network (MAN)
- 19. Network linking devices Computer networking devices, are physical devices which are required for communication and interaction between devices on a computer network.
- 20. Network Interface Card (NIC) • Hardware device that allows a computer to be connected to a network, both functionally and physically • Printed circuit board installed on to one of the expansion • Provides a attached slots of computer port on the back to which network cable is