CSCI 1101 Intro to Computers 6. Local Area Networks

ACS160 - Chapter 7 2 A computer network is a collection of computers and other devices that communicate to share data, hardware and software. Local area network (LAN) - a network located in a limited area.  found in most businesses Wide area network (WAN) - a network that covers a large geographical area Local Area Networks

ACS160 - Chapter 7 3 A local area network makes a stand-alone computer a workstation on a network. The workstation provides you with:  your computer’s local resources  hard drive, software  printer  access to network resources  software  storage space  other printers Benefits of Networking

ACS160 - Chapter 7 4 Network nodes include workstations printers, and servers. Typical Network Resources

ACS160 - Chapter 7 5 Page 309 You typically cannot use network resources until you log into the network.  provide user ID and password User account  provides access to network  accumulates information about network use  tracks when you log in and out Gaining Access to Networks

ACS160 - Chapter 7 6 Use these tips to select a secure password. Password Considerations

ACS160 - Chapter 7 7 Workstation gains access to the server when the server hard drive is “mapped” to a drive letter. Drive mapping - network term for assigning a drive letter to a network server disk drive.  many use the letter F Window’s Neighborhood Network is a utility that helps you see your workstation’s network drive mapping. What is drive mapping?

ACS160 - Chapter 7 8 When you start a program that is stored on a LAN, the program is copied to your workstation’s RAM, then runs normally. With proper licensing, many users on the same network can use the same program simultaneously, also known as sharing. Sharing is effective because:  less disk storage space required  easier to update software  less expensive Executing programs on a Network

ACS160 - Chapter 7 9 Advantages to storing data files on a server:  can access from any computer on network  other network users can access files  option of restricting access File locking - precaution that locks an open file so other users cannot open it at the same time Where to store data files

ACS160 - Chapter 7 10 Default printer - printer you most frequently use One way to select a different printer is to select a printer using the Printers dialog box. Printer Issues

ACS160 - Chapter 7 11 A network interface card (NIC) is the key hardware component for connecting a computer to a local area network.  small circuit board that sends data to and from workstation to network Different networks use different NICs. Popular network types include Ethernet and Token Ring. How to physically connect to a network

ACS160 - Chapter 7 12 Today’s networks use twisted-pair cable  UTP (unshielded twisted pair  STP (shielded twisted pair)  looks similar to telephone cable  has square plastic RJ-45 connector Twisted-pair cable Network Cabling

ACS160 - Chapter 7 13 Another option is coaxial cable  resembles cable-TV cable  round, silver BNC connector Coaxial cable More network cabling options

ACS160 - Chapter 7 14 Wireless networks use radio or infrared signals to transmit data from one network device to another.  handy in environments where wiring is difficult to install  historical buildings  provide mobility  good for temporary installations Non-wired network connections

ACS160 - Chapter 7 15 On most of today’s networks, the cable from a workstation NIC connects to a network hub, a device that joins communication lines together. A hub serves as a central connection point for workstation and server cables. Making the connection

ACS160 - Chapter 7 16 When connected to a network, the device that processes your data depends on the types of servers.  dedicated servers  non-dedicated servers  print servers  application servers  host computers Where does the actual processing occur?

ACS160 - Chapter 7 17 Application server - computer that runs a specific application software package  also referred to as client/server architecture An application server splits processing between the workstation (client) and the network (server). Client Server issues

ACS160 - Chapter 7 18 Page 321 An application server typically runs database software and performs database functions as requested by the workstations. Typical client/server work issues

ACS160 - Chapter 7 19 Some networks include a host computer, a minicomputer or a mainframe with attached terminals.  all processing takes place on the host  terminals only display results of processing  also known as a time-sharing system  Cyrix processing systems use this model Terminal emulation software connects a microcomputer to a host Centralized processing systems

ACS160 - Chapter 7 20 Today’s computers include software necessary to communicate with a network. The software handles the communication between your workstation and the network server. How networks communicate

ACS160 - Chapter 7 21 Network operating system (NOS) software  manages network resources  controls flow of data  maintains security  tracks user accounts Network operating system has two components  network server software  network client software Managing the network process

ACS160 - Chapter 7 22 Network server software (installed on file server)  controls file access from the server’s hard disk  manages print queue  tracks user data  IDs and passwords Network client software (installed on workstation)  gathers login information  handles drive mapping  directs printouts to network printer Network software components

ACS160 - Chapter 7 23 Most software designed for stand-alone computers can be installed on a network server. Some software has built-in networking features that only appear when software is installed on network.  ability to send a file to another network user What can I run on a network?

ACS160 - Chapter 7 24 Using a single-user license for multiple users typically violates software’s copyright. Software publishers offer a network license that allows use by multiple people on a network. Network software licensing

ACS160 - Chapter 7 25 Groupware is application software that supports collaborative work by managing:  schedules  shared documents  intra-group communications  based on “information-centered model Workflow software - automates the process of electronically routing documents from one person to another in a specified sequence  based on a “process-centered model” Group-based processing environments

ACS160 - Chapter messages are stored on a server and forwarded to you when you want to read it. (store-and-forward technology) How is communicated

ACS160 - Chapter 7 27 A gateway is an electronic link to other systems that allows you to send to people on other networks.  transferred through the gateway How gets to other systems

ACS160 - Chapter 7 28 Tips for using  read mail regularly  delete messages after you read them  you don’t have to reply to every  reply to one person instead of entire group  think before you send  don’t write anything confidential  don’t get sloppy  use proper netiquette Managing effectively