Network+ Certification (Outline) - Chapter 17: Network troubleshooting procedures

Chapter summary: Computers have a variety of ports, some of which are implemented by the motherboard and others by expansion cards; computers use many different types of connectors fortheir various interfaces, and in some cases the same connector type can provide different functions; SCSI host adapters can use any one of several types of connectors, which are not interchangeable;...
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Network+ Certification (Outline) - Chapter 17: Network troubleshooting procedures Chapter 17, Network Troubleshooting Procedures|1| Chapter Overview A. Identifying Network Components B. Troubleshooting a Network Chapter 17, Lesson 1 Identifying Network Components 1. Introduction A. Network technicians often have to troubleshoot problems on unfamiliar networks. B. When you work on an unfamiliar network installation, you should first determine the network’s basic hardware configuration. 1. You often must approach a problem without having any information about the network infrastructure and the equipment used to build it. a. In a perfect world, you would have access to schematic diagrams of the cabling and an inventory of the network hardware, but this rarely happens. C. Usually, you must examine the equipment yourself to find out what you need to know. 2. Recognizing Computer Ports A. Computers have many different ports. B. Most of the ports on computers manufactured today are labeled, but you might come across units that have no markings. 1. When ports are unlabeled, you must be able to discern their functions.|2| C. The ports on a typical computer are located either on the motherboard or on expansion cards that plug into the system bus. 1. If the same type of port can have more than one function, you can sometimes tell what a port does by where it is located. 2. The locations of the motherboard ports vary, depending on the design of the computer.|3| 3. An older computer might have the motherboard ports grouped in a separate area away from the motherboard itself. a. On an older computer, the motherboard ports are separate modules that are bolted to the back of the computer case and connected to the motherboard with cables. b. The expansion slots are grouped in a different area, where the ports provided by the expansion cards installed in the system are located.|4| 4. A newer computer might have all of the motherboard ports lined up in a row. a. On a newer computer, the ports are part of the motherboard. (1) The ports run horizontally along the bottom of the computer. (2) All ports are located on the motherboard, including the video port, which is typically provided by an expansion card. D. Serial ports 1. Modems nearly always use serial ports. a. A few proprietary networking systems use standard unshielded twisted-pair (UTP) cable that plugs into an adapter connected to a serial port.|5| 2. Computers manufactured today typically have two serial ports on the motherboard, both of which use male DB-9 connectors. 3. Older computers may also use DB-25 connectors for serial ports.|6| a. The typical configuration used to be one DB-9 connector and one DB-25 connector. 4. Because nine pins more than satisfy the requirements for serial communications, a computer can use either a DB-9 or a DB-25 connector. 5. Serial connections can run at speeds from 110 to 115,200 bits per second (bps). 6. D-type connectors are not used exclusively for serial ports. a. Parallel ports also use DB-25 connectors (although they are female instead of male). b. In rare cases, Small Computer System Interface (SCSI) adapters use DB-25 connectors. c. DB-9 connectors were at one time used as video ports for connections to monitors, although they were female instead of male. d. Do not confuse the various functions of DB-9 and DB-25 connectors; they are not interchangeable. E. Parallel ports 1. Parallel ports were designed for use by printers. a. In recent years, parallel ports have been enhanced to provide more efficient bidirectional communications between the computer and the attached device.|7| 2. Parallel ports always use a female DB-25 connector. 3. The average computer today has one parallel port. 4. A select group of SCSI devices can also be plugged into a computer’s parallel port. a. These devices use the same basic principles of communication as standard SCSI devices, but they use a different interface to the computer. b. The parallel port interface is slower than that of a dedicated SCSI host adapter. c. For many users, the ability to move a SCSI device from computer to computer without installing an adapter card is worth the sacrifice in speed. 5. Although nearly all computers today have two serial ports and one parallel port, you can use an input/output (I/O) expansion card to add ports. a. ...