Introduction to Networks Lesson 1

Objectives Exam Objective Matrix Technology Skill Covered Exam Objective Number Basic Definitions Describe different network topologies. Peer-to-peer Client-server 3.5 Basic Network Topologies Point-to-point Point-to-multipoint Ring Star Mesh Bus Hybrid 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 Hardware and software infrastructure Internet Service, or software, that runs on top of the infrastructure of the Internet World Wide Web

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

Most commonly used networking 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

Backbone cable is formed into a ring to connect all computers 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

Most commonly used in a WAN environment 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 A partial mesh network topology requires each device on the network to be able to connect to at least two other devices. A partial mesh network topology has all the same advantages as a full mesh topology where redundancy is concerned; however, it also has the added benefit that it does not require as many connections.

Mesh Topology Network A partial mesh network topology requires each device on the network to be able to connect to at least two other devices. A partial mesh network topology has all the same advantages as a full mesh topology where redundancy is concerned; however, it also has the added benefit that it does not require as many connections.

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 The network connection between the top ring, the middle router, and the bottom switch is an example of a bus topology. The connection between the router and the Internet cloud is an example of a point-to-point topology connection between the router and the Internet Service Provider (ISP) that provides access to the Internet for the entire 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 Similar to preceding figure but with one main difference. Instead of the central hub having a bus topology on the inside, it has a ring topology on the inside. A device like this is sometimes called a Token Ring Hub or a Ring Hub. One of the official names of a device like this is a MAU, which stands for Media Access Unit.

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: Open Control Panel. Double-click the Security icon. 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 city-wide 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.