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Introduction to Networks Lesson 1 Objectives Exam Objective Matrix Technology Skill Covered Exam Objective Exam Objective Number Basic Definitions Describe different network topologies. •Peer-to-peer •Client-server 3.5 Basic Network Topologies Describe different network topologies. •Point-to-point •Point-to-multipoint •Ring •Star •Mesh •Bus •Hybrid 3.5 Basic Network Configuration in Windows A Brief History of Networking • First networks called “sneaker nets” – Transferred files between computers on floppy disks • Mainframe computers and dumb terminals • Defense Advanced Research Projects Agency (DARPA) created ARPAnet – Became Internet • Mid 1980s – PCs common in workplace A Brief History of Networking (Continued) • Late 1980s – Businesses commonly networked PCs • July/August 1989 – BryanNet at William Jennings Bryan College – First general use high speed network – Through put speeds of 2.5 mbps (megabits per second) – Token ring – Client/server A Brief History of Networking (Continued) • Mid 1990s – World Wide Web established as a viable entity on the Internet Internet World Wide Web • Hardware and software infrastructure • Service, or software, that runs on top of the infrastructure of the Internet Local Area Network (LAN) • A network limited to a local area • Usually limited to one building, or several buildings near one another • Sometimes limited to certain rooms in a building Local Area Network (LAN) (Continued) • Peer-to-peer network – Each computer acts independently but can share data and resources, such as printers – Best used with 10 or fewer computers • Client/server – One main computer is server or domain controller – User accounts and resources available on one or more servers Wide Area Network (WAN) • A very large network that can stretch across large geographical areas – Internet is biggest WAN in existence • Enterprise network – WANs in a company’s offices or buildings in widely dispersed areas that connect facilities and employees Metropolitan Area Network (MAN) • A single network larger than a LAN but slightly too small to be considered a WAN • Is generally 50 kilometers maximum • Links college campuses or stretches across cities • Privately owned by an organization or publicly owned by a municipality • Term “MAN” falling out of usage, usually referred to as WAN or enterprise network Basic Network Topologies • Shape of network = topology – Bus – Star – Ring – Mesh – Point-to-Point – Point-to-Multipoint – Hybrid Bus Topology • All computers in network are connected by one main cable, called a backbone • Advantages – Easy to build and requires minimal amount of cable • Disadvantages – If cable breaks, networked computers cannot communicate – Signal collisions Bus Network Topology Star Topology • Most commonly used networking topology • Several workstations connected via one central device such as a hub or a switch • Advantage – If cable to one computer goes bad, only that computer is affected • Disadvantage – If central connecting device goes bad, entire network does not work Star Network Topology Ring Topology • Backbone cable is formed into a ring to connect all computers • Advantage – Use of token avoids data collisions • Disadvantages – If backbone breaks, entire network goes down – Network becomes very slow when large amounts of data are being sent Ring Topology Network Mesh Topology • Every computer or building is connected directly to every other computer or building • Most commonly used in a WAN environment • Number of connections: n (n–1) /2 • Advantages – Reliability, redundancy, high availability • Disadvantage – Number of connections grows quickly Mesh Topology Network Point-to-Point Topology • Only one computer is directly connected to one other computer or device • Primarily a WAN type topology • Most commonly used when a computer outside the network needs to remotely connect to a computer or server inside a network Point-to-Multipoint Topology • A variation on the point-to-point topology but commonly used in both LANs and WANs • One device connects to several other devices • Most often used to connect one switch or router to multiple switches, routers, computers, or other network devices Point-to-Multipoint Topology Network Hybrid Topology • A hybrid or combination of several network topologies • Most networks are hybrid Hybrid Topology Network Physical vs. Logical Topologies • Physical topology – The shape of the wires • Logical topology – The shape of the path the data follows as it moves through the network. Physical Star Topology Using a Logical Bus Topology Physical Star Topology Using a Logical Ring Topology Basic Network Configuration in Windows • User Account Control – A feature of Windows Vista and Windows 7 – Requires confirmation, and sometimes administrative passwords, to allow certain actions to be taken on a Windows Vista or Windows 7 computer, even when the person attempting the actions has administrative rights – Can become bothersome Basic Network Configuration in Windows (Continued) To turn off UAC in Windows Vista: 1. Open Control Panel. 2. Double-click the Security icon. 3. In the Security dialog box, turn off UAC in the Other security settings section. TIP: It’s best to leave UAC enabled for general users. Professionals may turn off UAC temporarily when maintaining PCs. Windows Vista Security Dialog Box Basic Network Configuration in Windows (Continued) • Network and Sharing applet in Windows 7 and Windows Vista • All issues related to networking and sharing of files, folders, media, and so on are located here Windows Vista Network and Sharing Center Dialog Box Summary • In organizations, PCs were common by the mid 1980s and networked PCs by the late 1980s. • The Internet is the hardware and software infrastructure on which the World Wide Web (a service or program) runs. • A LAN is a local network. A MAN is a campus or citywide network. A WAN covered a wide geographic area. • All computers are “equal” on a peer-to-peer network. Summary (Continued) • A client/server network has a server or domain controller to which users connect and access shared resources. • Network topologies include bus, star, ring, mesh, point-to-point, point-to-multipoint, and hybrid. • Physical topology refers to the shape of a network’s wires; logical topology is the shape of the path the data follows as it moves through a network. • In Windows 7 and Windows Vista, most networking configurations are performed in the Network and Sharing Center.