Chapter 1: Introduction to Computer Networks and Data Communications Data Communications and Computer Networks: A Business User’s Approach Third Edition

Data Communications & Computer Networks: A Business User's Approach, Third Edition2 Objectives After reading this chapter, you should be able to: Define the basic terminology of computer networks Recognize the individual components of the big picture of computer networks Outline the basic network configurations Cite the reasons for using a network model and explain how they apply to current network systems

Data Communications & Computer Networks: A Business User's Approach, Third Edition3 Objectives (continued) List the layers of the OSI model and describe the duties of each layer List the layers of the TCP/IP protocol suite and describe the duties of each layer Compare the OSI model and TCP/IP protocol suite and list their differences and similarities

Data Communications & Computer Networks: A Business User's Approach, Third Edition4 Who today has not used a computer network? Mass transit, interstate highways, 24-hour bankers, grocery stores, cable television, cellular telephones, most businesses and schools, and other retail outlets can support some form of computer networks Introduction

Data Communications & Computer Networks: A Business User's Approach, Third Edition5 The Language of Computer Networks Computer network - an interconnection of computers and computing equipment using either wires or radio waves over small or large geographic distances Local area network - networks that are small in geographic size spanning a room, building, or campus Metropolitan area network - networks that serve an area of 3 to 30 miles - approximately the area of a typical city

Data Communications & Computer Networks: A Business User's Approach, Third Edition6 The Language of Computer Networks Wide area network - a large network that encompasses parts of states, multiple states, countries, and the world Data communications - the transfer of digital or analog data using digital or analog signals Voice network - a network that transmits telephone signals Data network - a network that transmits computer data

Data Communications & Computer Networks: A Business User's Approach, Third Edition7 The Language of Computer Networks (continued) Telecommunications - the study of telephones and the systems that transmit telephone signals Network management - the design, installation, and support of a network and its hardware and software Personal area network – a network of a few meters, between wireless devices such as PDAs, laptops, and similar devices

Data Communications & Computer Networks: A Business User's Approach, Third Edition8 The Big Picture of Networks Networks are composed of many devices, including: Workstations (computers and telephones) Servers Network hubs and switches (bridges) Routers (LAN-WAN and WAN-WAN) Telephone switching gear

Data Communications & Computer Networks: A Business User's Approach, Third Edition9 The Big Picture of Networks (continued)

Data Communications & Computer Networks: A Business User's Approach, Third Edition10 Computer Networks - Basic Configurations Computer terminal/microcomputer to mainframe computer Microcomputer to local area network Microcomputer to Internet Local area network to local area network Personal area network to workstation

Data Communications & Computer Networks: A Business User's Approach, Third Edition11 Computer Networks – Basic Configurations (continued) Local area network to metropolitan area network Local area network to wide area network Sensor to local area network Satellite and microwave Wireless telephone and wired telephone to network

Data Communications & Computer Networks: A Business User's Approach, Third Edition12 Terminal/microcomputer-to-mainframe Computer Configurations Predominant form in 60s and 70s Still used in many types of businesses for data entry and data retrieval Usually involves a low-speed connection

Data Communications & Computer Networks: A Business User's Approach, Third Edition13 Terminal/microcomputer-to- mainframe Computer Configurations (continued)

Data Communications & Computer Networks: A Business User's Approach, Third Edition14 Microcomputer-to-Local Area Network Highly common throughout business and academic environments, and now even homes Typically a medium- to high-speed connection Microcomputer requires a NIC (network interface card) NIC connects to a hub-like device

Data Communications & Computer Networks: A Business User's Approach, Third Edition15 Microcomputer-to-local Network Configurations (continued)

Data Communications & Computer Networks: A Business User's Approach, Third Edition16 Microcomputer-to-Internet Configurations Very popular with home users and some small businesses Typically, a dial-up modem is used to connect user’s microcomputer to an Internet service provider Newer technologies such as DSL and cable modems are replacing modems

Data Communications & Computer Networks: A Business User's Approach, Third Edition17 Microcomputer-to-Internet Configurations (continued)

Data Communications & Computer Networks: A Business User's Approach, Third Edition18 Local Area Network-to-Local Area Network Configurations (continued) Found in businesses and schools that have two or more LANs and a need for them to intercommunicate A bridge-like device (such as a switch) is typically used to interconnect LANs Bridge-like device can filter frames

Data Communications & Computer Networks: A Business User's Approach, Third Edition19 Local Area Network-to-Local Area Network Configurations (continued)

Data Communications & Computer Networks: A Business User's Approach, Third Edition20 Personal Area Network-to-Workstation Configurations Interconnects wireless devices such as PDAs, laptops, and music playback devices Used over a short distance such as a few meters

Data Communications & Computer Networks: A Business User's Approach, Third Edition21 Personal Area Network-to-Workstation Configurations (continued)

Data Communications & Computer Networks: A Business User's Approach, Third Edition22 Local Area Network-to-Metropolitan Area Network Configurations Used to interconnect companies (usually their local area networks) to networks that encompass a metropolitan city High speed networks with redundant circuits

Data Communications & Computer Networks: A Business User's Approach, Third Edition23 Local Area Network-to-Metropolitan Area Network Configurations (continued)

Data Communications & Computer Networks: A Business User's Approach, Third Edition24 Local Area Network-to-Wide Area Network Configurations One of the most common ways to interconnect a user on a LAN workstation to the Internet (a wide area network) Router Typical device that performs LAN to WAN connections More complex devices than bridges/switches

Data Communications & Computer Networks: A Business User's Approach, Third Edition25 Local Area Network-to-Wide Area Network Configurations (continued)

Data Communications & Computer Networks: A Business User's Approach, Third Edition26 Wide Area Network-to-Wide Area Network Network Configurations High-speed routers and switches are used to connect one wide area network to another Thousands of wide area networks across North America Many interconnected via these routers and switches

Data Communications & Computer Networks: A Business User's Approach, Third Edition27 Sensor-to-Local Area Network Configurations Not all local area networks deal with microcomputer workstations Often found in industrial and laboratory environments Assembly lines and robotic controls depend heavily on sensor-based local area networks

Data Communications & Computer Networks: A Business User's Approach, Third Edition28 Sensor-to-Local Area Network Configurations (continued)

Data Communications & Computer Networks: A Business User's Approach, Third Edition29 Satellite and Microwave Configurations Long distance wireless connections Many types of applications including long distance telephone, television, radio, long-haul data transfers, and wireless data services Typically expensive services but many companies offer competitive services and rates

Data Communications & Computer Networks: A Business User's Approach, Third Edition30 Satellite and Microwave Configurations (continued)

Data Communications & Computer Networks: A Business User's Approach, Third Edition31 Wireless Telephone Configurations Constantly expanding market across the U.S. and world Second generation PCS services available in most areas and under many types of plans Next generation services beginning to replace PCS phones

Data Communications & Computer Networks: A Business User's Approach, Third Edition32 Wireless Telephone Configurations (continued)

Data Communications & Computer Networks: A Business User's Approach, Third Edition33 Wireless Telephone Configurations (continued) An additional basic configuration is telephone to network Telephone systems are ubiquitous and can now carry more data than voice Common configuration – telephone connected to POTS Newer configuration – telephone to LAN via gateway (VoIP)

Data Communications & Computer Networks: A Business User's Approach, Third Edition34 Network Architectures Reference model that describes the layers of hardware and software necessary to transmit data between two points or for multiple devices / applications to interoperate Reference models are necessary to increase the likelihood that different components from different manufacturers will converse Two architectures are required learning: The OSI Model, and the TCP/IP protocol suite

Data Communications & Computer Networks: A Business User's Approach, Third Edition35 The Open Systems Interconnection (OSI) model

Data Communications & Computer Networks: A Business User's Approach, Third Edition36 The Open Systems Interconnection (OSI) model (continued) Application layer - where the application using the network resides Common network applications include remote login, file transfer, , and web page browsing Presentation layer - performs series of miscellaneous functions necessary for presenting the data package properly to the sender or receiver

Data Communications & Computer Networks: A Business User's Approach, Third Edition37 The Open Systems Interconnection (OSI) model (continued) Session layer - responsible for establishing sessions between users Transport layer - provides end-to-end error-free network connection Makes sure data arrives at destination exactly as it left the source Network layer - responsible for creating, maintaining and ending network connections Transfers a data packet from node to node within the network

Data Communications & Computer Networks: A Business User's Approach, Third Edition38 The Open Systems Interconnection (OSI) model (continued) Data link layer - responsible for taking data and transforming it into a frame with header, control and address information, as well as error detection code Physical layer - handles the transmission of bits over a communications channel Includes voltage levels, connectors, media choice, modulation techniques

Data Communications & Computer Networks: A Business User's Approach, Third Edition39 The Open Systems Interconnection (OSI) model (continued)

Data Communications & Computer Networks: A Business User's Approach, Third Edition40 The TCP/IP Protocol Suite

Data Communications & Computer Networks: A Business User's Approach, Third Edition41 The TCP/IP Protocol Suite (continued) Application layer - equivalent to the OSI’s presentation and application layers Transport layer - performs same function as OSI transport layer Network (Internet or internetwork) layer - roughly equivalent to the OSI’s network layer Network access (data link/physical) layer - equivalent to the OSI’s physical and data link layers

Data Communications & Computer Networks: A Business User's Approach, Third Edition42 Logical and Physical Connections Logical connection – exists only in the software Physical connection – exists in the hardware In a network architecture Only lowest layer contains physical connection All higher layers contain logical connections

Data Communications & Computer Networks: A Business User's Approach, Third Edition43 Logical and Physical Connections (continued)

Data Communications & Computer Networks: A Business User's Approach, Third Edition44 Logical and Physical Connections (continued)

Data Communications & Computer Networks: A Business User's Approach, Third Edition45 Network Configurations in Action

Data Communications & Computer Networks: A Business User's Approach, Third Edition46 The TCP/IP Protocol Suite in Action Note the flow of data from user to web browser and back At each layer, information is either added or removed Depends on whether data is leaving or arriving at a workstation Encapsulation - adding information over pre-existing information

Data Communications & Computer Networks: A Business User's Approach, Third Edition47 The TCP/IP Protocol Suite in Action (continued)

Data Communications & Computer Networks: A Business User's Approach, Third Edition48 Summary Basic terminology of computer networks Individual components of computer networks Basic network configurations Network models and how they apply to current network systems Layers of the OSI model and the TCP/IP protocol suite