Lesson 2-4: Ethernet Standards

Transcription

1 Unit 2: LAN Configurations Lesson 2-4: Ethernet Standards At a Glance The lesson discusses several Ethernet and IEEE standards. Ethernet s frame format and media access protocols were covered in the previous lesson. This lesson covers Ethernet s signaling components and cabling. A comparison among 10BASE5, 10BASE2, 10BASE-T, 10BASE-F, and 100BASE-T (Fast Ethernet) standards as well as media characteristics will be covered. What You Will Learn After completing this lesson, you will be able to: Identify the characteristics of the various IEEE Ethernet LANs. Compare and contrast the characteristics of the various IEEE Ethernet LANs. Describe the characteristics and functions of the components used in Ethernet networks. Build and troubleshoot an Ethernet network. Design an Ethernet network. ST A 203

2 Lesson 2-4 Ethernet Standards Tech Talk Attachment Unit Interface (AUI) An electrical and mechanical interface defined by the IEEE (10 Mb/s) standard. A transceiver cable sometimes called a drop cable, and the 15-pin connector used to connect a NIC to an external transceiver. External transceivers are used in 10BASE5 Ethernet networks. BNC T Connector The interface used to connect Ethernet 10BASE2 cable directly to the NIC and the coaxial cable. Daisy chain Devices connected in series, one after the other. Transmitted signals go to the first device, then to the second device and on until finding the destination. Fan-out unit A fan-out unit is a single transceiver that connects multiple receivers. Fiber Optic Medium Access Unit (FOMAU) A type of transceiver used for fiber to copper connections. The two types of connections that can be used are AUI to fiber or 10BASE-T and RJ-45 to fiber. Intrusive Tap A connection in 10BASE5 networks that necessitates cutting the cable and requires that the network be shut down. Media Access Unit (MAU) Point at which the data signals access (transmit and receive) the physical media. A MAU is another name for the external transceiver used in 10BASE5 networks. Another name for a MAU is a vampire tap. Media Dependent Interface (MDI) The IEEE standard for the interface to unshielded twisted pair (UTP) cable. The connection is established through a crossover function, which can be a crossover cable or a port that implements the crossover function internally. Ports that implement the crossover function internally are known as MDI-X ports. N-Connector A type of media dependent interface used with thick coaxial cable that allows a connection at the core of the cable and is used to join two ends of thick coaxial cable. Non-Intrusive Tap A connection used in 10BASE5 networks that does not require a cut into the cable. Square-Connector (SC)--Ports used for fiber optic connections that are square tabbed connectors on the end of the fiber cable. Straight-Tip Port (ST) Ports used for fiber optic connections that connect bayonet style connectors on the ends of the fiber cable. 204 ST A Internetworking Fundamentals

3 Unit 2: LAN Configurations Transceiver A device that transmits and receives the data signals for a given media. Transceivers are usually part of a NIC. Ethernet Standards Ethernet standards define several elements that enable transmission of data over LANs. Ethernet refers to both the original DIX Ethernet and IEEE s specifications. Data link layer protocols were discussed in the Ethernet Basics lesson. This lesson focuses on the physical layer protocols, comparing various Ethernet signaling devices and physical media. The IEEE Ethernet CSMA/CD architecture is based on the original DIX format established in the early 1980s by Digital, Intel, and Xerox. Ethernet employs physical/logical bus and physical star/logical bus topology. Current Ethernet networks use a combination of copper and fiber optic cabling. The IEEE cabling standards recommend the specifications for cable types, lengths, signaling devices, and so on. Ethernet standards change as the demands and needs of networking change. With each change, new protocols are established. The naming schemes for each of the Ethernet standards assist with the identification of transmission type and cable used. For example, 10BASE5 is a 10 Mbs baseband transmission with a 500 meter distance limitation and 100BASE-T is a 100 Mbs baseband transmission using category 5 UTP cabling. Ethernet 10BASE5 The 10BASE5 standard describes the original Ethernet DIX LAN. It is a linear bus topology design where all of the computer devices are connected together to a common shared cable. 10BASE5 transmissions are 10 Mbs baseband as the name suggests. Recall that baseband signals use the entire bandwidth for signaling. The 5 in the name also gives us information about the network topology. It represents the maximum length for each cable segment, in this case, 500 meters. The cable type used for 10BASE5 is thick coaxial RG-8 or RG-11 with a 50 ohm resistance. Thick coaxial, also known as thicknet, is an inexpensive cable that provides superior protection against EMI, which makes it preferable choice for noisy environments. On the negative side, thick coax, which is about the thickness of a rubber garden hose, is cumbersome and difficult to work with and takes up a lot of space. Since thick coaxial cannot operate at speeds higher than 10Mbs, its usefulness is limited in higher speed networks. Because of these factors, thicknet has been phased out of networks and is being replaced with fiber. ST A 205

4 Lesson 2-4 Ethernet Standards IEEE 10BASE5 specifications allow for a total of five cable segments per LAN. Therefore, 10BASE5 LANs may have a total cable length of up to 2,500 meters. Because of the extended length allowances and superior EMI protection, thick coax was once considered the best choice for backbone cabling. Up to four repeaters may be used to connect these cable segments to the LAN, however, only three of the segments can have devices. Extending the length of the LAN is the only function of the two additional cable segments. The five cable segment and four repeater limitations and the fact that only three of the cable segments may be used for transceivers is referred to as the Ethernet Rule. Each of the three cable segments that are allowed to have devices may have up to 100 transceivers (taps) attached. Transceivers will be explained later in this lesson. A minimum of 2.5 meters between transceivers is recommended. Each cable segment must be terminated at both ends with one of the ends grounded. Termination of the cable prevents signal bounce-back. Ethernet DIX standards allow a maximum of 1,024 computer devices per LAN. Minimum 2.5 Meters Between Transceivers Minimum of 2.5 meters between transceivers Transceiver Transceiver 10Base5 Cable Attachment Unit Interface Transceiver cable If only three of the five cable segments can be used for transceivers and the limit is 100 transceivers per segment, why do the standards allow up to a 206 ST A Internetworking Fundamentals

5 Unit 2: LAN Configurations maximum of 1,024 devices? It would appear that the maximum should be 300. It is the number of transceivers that are limited to 100 per segment, not the number of computer devices. A fan-out unit, a single transceiver that can accommodate multiple connections, may have up to 8 devices attached. Since this requires only one transceiver connection, the 100- transceiver limitation actually allows more than 100 devices to be connected to a cable segment. Care must be used when daisy chaining fanout units. The single transceiver is a shared device, so signal delays may occur causing higher rates of collisions, which may slow down or completely disable the network. 10BASE5 Components Media Access Unit (MAU) A media access unit (MAU), as the name implies, is the point at which the data signals access the physical media. A MAU is another name for the external transceiver used in 10BASE5 networks. It provides the electrical connection and transmits signals between the Ethernet interface and network. A MAU is a combination of a transceiver and a tap. Taps may be either intrusive or non-intrusive. When using non-intrusive taps, it is not necessary to cut into the cable. A non-intrusive connection is achieved with the use of a device that clamps around the cable and inserts a sharp metal probe through the core of the cable. An intrusive tap uses the core of the cable as the connection point and requires cutting the cable, which necessitates shutting down the entire network. N-Connector An N-connector is a type of Media Dependent Interface (MDI) connector used with thick coaxial cable. It allows a connection at the core of the cable and is used to join two ends of thick coaxial cable. An MDI is simply the piece of hardware that makes the direct physical and electrical connection to the cable. Installation of N-connectors requires an intrusive tap, cutting directly into the cable. Special stripping and crimping tools are needed for installation purposes and care must be taken not to damage the cable or signal problems will result. An N-connector can also serve as a connection point for transceivers or fan-out units (transceivers with multiple ports). ST A 207

6 Lesson 2-4 Ethernet Standards Attachment Unit Interface (AUI) and Connector An AUI is a transceiver cable, also called drop cable, and is used to connect a NIC to an external transceiver. Drop cables may run a maximum of 50 meters from the transceiver (MAU) to the computer device. The AUI cable length is not included as part of the 500 meter per segment IEEE specification. Transceiver, Transceiver Cable (AUI), and DIX (AUI) Connector Transceiver cable DIX connector Transceiver AUI An AUI connector, sometimes called a DIX connector, is a 15-pin connector used to connect a drop cable to a NIC. 208 ST A Internetworking Fundamentals

7 Unit 2: LAN Configurations Check Your Understanding Complete the following chart. 10BASE5 Cable type Maximum cable segment length Maximum number of cable segments Maximum total cable length per LAN Maximum number of repeaters per LAN Maximum number of transceivers (taps) per segment Minimum distance between transceivers Maximum number of segments that may have devices Maximum number of devices per LAN Name each of the 10BASE5 components and explain their function. What are some of the advantages and disadvantages of 10BASE5 LANs? ST A 209

8 Lesson 2-4 Ethernet Standards Ethernet 10BASE2 10BASE2 is the IEEE Ethernet standard proposed in Signaling is baseband at a speed of 10 Mbs over physical/logical bus architecture using 50-ohm thin coaxial cable. The 2 in 10BASE2 represents the approximate cable segment length, which is 185 meters. Thin coaxial is less expensive and more flexible than thick coaxial, which makes it easier to install. However, thin coax is more susceptible to EMI resulting in the significantly shorter length specification. The shorter distance limitation, however, makes it easier to troubleshoot. If distance and EMI are not main concerns, 10BASE2 is generally the more economical. Both thin and thick coaxial are compatible with one another and are often used on the same network, with thin cable located in the offices and thick cable in the ceilings and walls. When upgrades are made to networks, it is common for 10BASE2 cabling to be replaced with the newer 10BASET, which is explained later in this lesson. The rule also applies to 10BASE2 networks allowing up to five cable segments, four repeaters, and three segments with devices. Use of all five segments extends the network length to approximately 925 meters. Only 30 taps per segment are permitted under 10BASE2 specifications, with a minimum distance between taps of 0.5 meters. Once again, the maximum number of network devices is BASE2 has two versions, one uses external transceivers and can support either single or multiple devices. The other version uses built-in transceivers, which means that fan-out units can not be used and each transceiver supports only one device. Fan-out units are necessary to build a medium to large network. 10BASE2 Components MAUs and AUIs When an external transceiver (MAU) is used, an attachment unit interface (AUI) and/or connector is needed to ensure that the signals can be transmitted across the 10BASE2 cable. 210 ST A Internetworking Fundamentals

9 Unit 2: LAN Configurations BNC Connector Connects NIC Directly to the 10BASE2 Cable BNC T Connector BNC T Connector 10Base2 Cable British Naval Connectors (BNC) Ethernet interfaces with built in transceivers can attach directly to the cable. This is done using a BNC T Connector. One end of the T connector connects directly to the NIC interface; the ThinNet cable is attached to the other two T connector openings. Check Your Understanding Complete the following chart. 10BASE2 Cable type Maximum cable segment length Maximum number of cable segments Maximum total cable length per LAN Maximum number of repeaters per LAN Maximum number of taps per segment Minimum distance between taps Maximum number of devices per LAN ST A 211

10 Lesson 2-4 Ethernet Standards What are some of the advantages and disadvantages of 10BASE2 networks? Name the 10BASE2 components and explain their function. Ethernet 10BASE-T As networks expanded, cost became an issue and the demand for less expensive LANs increased. The 10BASE-T standard, published in 1990, used twisted (T) pair cable and specifications that enabled networks to use existing telephone cabling, often already installed in buildings. Use of twisted pair cabling reduced costs and made installation much easier. 10BASE-T uses either 100-ohm unshielded twisted pair or 150 ohm shielded twisted pair cabling. It supports different signal speeds depending upon the cable type. The maximum cable segment distance is 100 meters, 90 meters from the wiring closet and another 10 meters shared between the wiring closet and office space. These smaller cable segments are called patch cables. The maximum number of cable segments is 1,024 with up to two devices connected to each cable segment. If an Ethernet LAN did have 1024 devices, it would not be functional because of excessive collisions from everyone trying to access the network at the same time. In reality the maximum number should be no more than 200 or so devices with often as few as 5 or 10 devices. 10BASE-T is a Physical Star/Logical Bus Topology 10BaseT cable BayStack BaseT Hub 212 ST A Internetworking Fundamentals

11 Unit 2: LAN Configurations The topology of 10BASET, while logically a bus, is physically a star. Recall that bus topology is a cable with devices directly attached to the same cable. The star configuration is created when devices are connected by way of a single cable to a single point, a hub. The hub repeats the transmission to all of the devices on the network and the devices contend for access as if they were a bus topology. The maximum number of daisy-chained hubs is four. 10BASE-T offers low cost, flexibility in design, ease of installation and troubleshooting, and a choice of cable types. In addition, it can be mixed with 10BASE5 or 10BASE2. Unshielded Twisted Pair (UTP) 10BASE-T UTP cable is a 100 ohm cable with 4 twisted pairs, and a maximum cable distance of 100 meters. The three UTP cable categories are: Category 3: Supports up to 16 Mbs Category 4: Supports up to 20 Mbs Category 5: Supports up to 1000 Mbs Networks built today use category 5 cabling to ensure that a network may be upgraded to faster speeds. Shielded Twisted Pair (STP) 10BASE-T STP cable is a 150 ohm cable with 4 pairs and a maximum cable distance of 100 meters. STP may be used to connect devices to hubs. When mixing STP and UTP cabling, it may be necessary to use a resistance matching device because of the resistance difference. 10BASE-T Connectors and Ports The ports on hubs are configured as Media Dependent Interface with Crossover (MDI-X) ports. The RJ-45 port on the back of a NIC is a Media Dependent Interface MDI port. The transmit and receive connections of the two ports are opposite of each other. The pairs used by MDI to transmit are used to receive on an MDI-X connection and vice versa. This twisted pair arrangement allows transmitting and receiving of signals to take place. ST A 213

12 Lesson 2-4 Ethernet Standards NIC With 8-Pin RJ-45 and BNC Coaxial Connectors RJ-45 Connector BNC Coaxial Connector There are two types of RJ-45 connectors, MDI-X RJ-45 connectors and MDI RJ-45 connectors. You cannot connect a MDI RJ-45 connector to another MDI RJ-45 connector; it must be connected to an MDI-X RJ-45 connector. If the connectors are the same a special type of cable, a crossover cable is required. Patch cables with RJ-45 connectors at each end are used to connect the devices to the NICs in the back of the devices and the hubs in the wiring closet. 214 ST A Internetworking Fundamentals

13 Unit 2: LAN Configurations Check Your Understanding Complete the following chart. When you know the chart is correct, copy it into your portfolio for future reference. 10BASE-T Cable type Maximum cable segment distance Maximum number of cable segments Maximum number of repeaters/hubs per LAN How do UTP Ethernet resistance standards differ from STP Ethernet standards? What speeds do the various categories of UTP cabling support? Name the 10BASE-T connectors and ports and explain their function. ST A 215

14 Lesson 2-4 Ethernet Standards Ethernet 10BASE-F 10BASE-F, where F means fiber, defines a 10 Mbs network connected with a 62.5/125 µs multi-mode fiber optic cable. Multi-mode fiber uses an LED signal and has a maximum distance of 2,000 meters. It has a defined maximum attenuation of 3.75 db/km for 850nm wavelength transmissions, and 1.5 db/km for 1300 wavelength transmissions. 10BASE-F Maximum Distance 2,000 Meters Building 1 Terminator Repeater Building meters The maximum number of devices per segment is 2, with a 1024 maximum number of segments, each of which may have a device attached, up to a maximum of 1024 devices. 10BASES-F topology requires a hub to receive the signal from the network device and is therefore a physical star topology. In addition to allowing increased cable lengths, fiber optic cable has several other advantages over copper cable. It is not subject to EMI, cannot be tapped into, and no unknown devices can be added to the network. Its extremely high bandwidths allow transmission speeds from 100 Mbs to over 2 gigabits per second. Although it is more expensive and difficult to install than twisted pair or coax cable, it is now the preferred cable to use as a network backbone. As the price of fiber continues to drop, it will become more common in networks. 10BASE-F Components Fiber Optic Medium Access Unit (FOMAU) A transceiver must be used to connect a network interface card with a fiber cable. There are two types of connections which may be used, AUI to fiber or 10BASE-T RJ-45 to fiber. The transceiver is called a FOMAU for fiber to copper connection. FOMAU provides access by converting electrical signals to optical signals. 216 ST A Internetworking Fundamentals

15 Unit 2: LAN Configurations Straight-tip (ST) Ports The ports used for fiber optic connections are called straight tip or ST ports. They connect to bayonet style connectors on the ends of the fiber cable. Square-Tip (SC) Ports SC fiber optic connections are quickly replacing ST connectors as they are more durable and the crossover at each end for transmit and receive is standardized. Each port has two connectors, one to transmit and one to receive. When a fiber connection is made, each end must be connected in the opposite manner. The cable ends are usually color coded red and black. If the red connector on one end of the cable is plugged into the transmit connector, then the red connector on the other end of the cable must be plugged into the receive connector. Ethernet 100BASE-T (Fast) Ethernet 100BASE-T is basically the same as 10BASE-T with two important differences: it runs at a faster rate and it has a full duplex capacity, which means that it can send and receive packets simultaneously. Although very similar to 10BASE-T, several changes have increased the transmission speed. Some of the adjustments include reducing the maximum cabling distance to 250 meters, limiting the network to no more than two repeaters, increasing the clock signal, and decreasing the time for transmission of bits. To make these changes and still remain Ethernet compatible, a sub-layer was added to the OSI MAC sub-layer. There are three media types specified by the 100BASE-T standards. The 100BASE-T4 uses category 3, 4, or 5 STP or UTP cable, 100BASE-TX uses category 5 STP or UTP cable, and 100BASE-FX uses duplex fiber optic cable. Since 10BASE-T Ethernet environments utilize category 5 cable, some minor modifications to an existing LAN can convert it to a 100Mbs environment. Simply replace the NICs with 10/100 base Ethernet NICs, make sure you are using category 5 cabling, and replace the 10BASE-T hub with a hub designed for Fast Ethernet environments. ST A 217

16 Lesson 2-4 Ethernet Standards Check Your Understanding Complete the following chart. 10BASE-F Cable type Maximum number of devices per segment Maximum cable segment length Maximum number of devices per segment Transmission speeds Describe a 100BASE-T Ethernet network. What is a FOMAU? What type of connectors are attached to the ends of fiber cable? Explain how to convert from a 10BASE-T Ethernet LAN to a 100BASE-T LAN. 218 ST A Internetworking Fundamentals

17 Unit 2: LAN Configurations Try It Out Determining Cabling Distances using Microscanner In this lesson, you learned that cabling must not exceed a maximum distance. Although your network may still function with cabling that exceeds the maximum distance limitations, manufacturers will not honor their warranties if you do not adhere to IEEE specifications. Materials Needed Microscanner Several Patch Cables of various lengths In this activity, you will use a microscanner to determine the length of various cables. Your teacher will provide you with various patch cables and/or instruct you on which areas of your network to investigate. Directions: Obtain the microscanner and test the lengths of at least 10 different cables. 1. Insert the RJ-45 connector of the cable to be tested into the main port. 2. Turn the microscanner on and press the mode button until the LED reaches the length screen. 3. The length of the cable will be displayed on the LED. Record the information is the space provided below. WIRETRAP Length FAULT ft ON OFF MODE ST A 219

18 Lesson 2-4 Ethernet Standards Cable #1: Length Cable Type: Cable Location Cable #2: Length Cable Type: Cable Location Cable #3: Length Cable Type: Cable Location Cable #4: Length Cable Type: Cable Location Cable #5: Length Cable Type: Cable Location Cable #6: Length Cable Type: Cable Location Cable #7: Length Cable Type: Cable Location Cable #8: Length Cable Type: Cable Location Cable #9: Length Cable Type: Cable Location Cable #10: Length Cable Type: Cable Location Are the cables all within the IEEE recommended distance allowances? If not, report your findings to your teacher. 220 ST A Internetworking Fundamentals

19 Unit 2: LAN Configurations Cascading Hubs into a Hub Stack Ethernet LANs may be configured in several ways. In this lab, you will cascade two or more Ethernet hubs using the MDI MDI-X port. Work in groups of three or four. All the members of your team will connect their computers to the hubs creating a Multiple Hub Ethernet LAN. Record your actions and any problems, successes, or comments you may have in your portfolio. In this activity you will configure a LAN using two hubs. The following is a review of straight through and crossover ports. Ports on hubs that connect to network devices are called host ports. Host ports are configured as Media Dependent Interface with Crossover (MDI-X) ports. An RJ-45 port on the back of a NIC is an MDI (Media Dependent Interface) port, meaning the wires are straight through. When two ports transmit data, they must transmit signals over transmit pairs and receive signals over the receive pair of wires. Transmit and receive connections are known to be opposite to each other. Think about talking on the telephone as transmitting and listening as receiving. The two functions are opposites; you transmit at one end of the phone and receive on the other. On twisted pair cable, a different pair of wires handles each of these functions. Twisted pair wire has 4 pairs (8 wires); with 1 pair used to transmit signals and 1 pair used to receive signals. Refer to the cable crimping activity diagrams in the cabling lesson for review. Read pages 2-1 through 2-4 before beginning this activity 1. Disconnect all connectors (except power) from the hubs. Which ports on each hub are configurable to MDI or MDI-X? What is the configuration of all other ports? MDI or MDI-X Explain how you know which ports are MDI and which are MDI-X? 2. Choose a UTP cable to use to connect the two hubs together using a connection of MDI to MDI-X. What cable did you choose? Straight through or cross-over? 3. Configure the port to be an MDI port on the first hub. ST A 221

20 Lesson 2-4 Ethernet Standards How should you configure the second hub s port 1? Explain your answer. 4. Using a patch cable, connect the MDI port of a hub to any MDI-X port of another hub. If you have more than two hubs, connect them all using the same method. When you connect the cables does the LED light go on? Yes or No. If Yes, what color is the LED? Green or amber. What does the color indicate? Refer to your portfolio for an explanation of the hub s port status LEDs. 5. Connect the team computers to the network of hubs. Verify that all LEDs are green. 6. Ping all computers attached to the network. If any fail, determine the problem and verify correction with a successful ping. How many collision domains have you created? 7. Diagram the cascading hubs. Rubric: Suggested Evaluation Criteria and Weightings Criteria % Your Score Participation 20 Problems, successes, and/or comments entered in Portfolio 20 Accurately follows directions 20 Accurate diagram of multiple hub configuration, including labels Completeness and accuracy of answers to lab questions TOTAL ST A Internetworking Fundamentals

21 Unit 2: LAN Configurations Stretch Yourself Troubleshooting Ethernet Multiple Hub LANs In the previous activity, you created a multiple hub LAN configuration. In this activity, you will refer to the hub documentation supplied by your teacher and answer the following questions. Materials Needed BayStack 152 or 153 Hub documentation Describe what the following Hub Status and Port LEDs indicate. Place your answers in your portfolio for future reference. When the In is green, what does that indicate? When the Out is green, what does that indicate? When the Col is amber, what does that indicate? When the Collision/1, 5, 20 is amber, what does that indicate? When the Utilization % is green, what does that indicate? When the Link/Rx is green, what does that indicate? When the Link/Rx is blinking, what does that indicate? When the Disable is yellow, what does that indicate? When the autopartition is yellow, what does that indicate? Answer the following questions about the rear panel ports of the BayStack hubs. Your instructor will supply you with the documentation that came with the hubs. Describe the Cascade In and Out ports. How many hubs can you connect in a stack? What is the maximum number of ports you can utilize? What is the Comm Port used for? What type of connector does the Comm Port accept? What is the AUI port used for? ST A 223

22 Lesson 2-4 Ethernet Standards Rubric: Suggested Evaluation Criteria and Weightings Criteria % Your Score On time delivery of assignment 15 Questions and answers added to portfolio for future reference. Completeness and accuracy of answers questions 60 TOTAL ST A Internetworking Fundamentals

23 Unit 2: LAN Configurations Network Wizards Proposing an Ethernet Network Design Check with school administrators before you complete this activity. You can propose an Ethernet LAN design according to the sample specifications given below. However, if your school is planning on extending their network, obtain the specifications from the school administration and use that information to create your network design proposal. Materials Needed None Request for Proposal Your school wants to network a computer lab, the administration building, and the teachers lounge. The number of computer lab devices to be networked is 55: 45 workstations, and 10 printer connections. Both the teachers lounge and the administration office have 5 workstations and 1 printer each. The particular specifications are listed below. It has been decided that Ethernet will be installed. You have been hired to submit a design proposal. The network is to be a single collision domain. Money is a primary concern since the budget is tight. Create a single domain network selecting the best components, cables, and configuration. Place the correct number of devices in their proper locations on your design. Be sure the design is fully documented, easy to read and follow. Justify your design according to the IEEE standards. For example the rule, numbers of devices per fan-out unit, segment, etc. Indicate why you chose the cable types. Work in groups of five. In addition to the design itself, a company must be concerned with the quality and creativity of the design and presentation. Appoint one member of the group the marketing/graphic design expert, one or two Ethernet specialists, and one a sales/financial specialist. The group should brainstorm the basic design and each of the team specialists should prepare a written document covering the particulars of his/her area of expertise. For example, the sales/financial expert should prepare a spreadsheet of the cost of the various components. ST A 225

24 Lesson 2-4 Ethernet Standards Meet with the group to share your findings and prepare the final presentation to the potential clients. You will need to present your design to the network committee in a professional manner, professionally attired, with all the necessary documentation. Complete this assignment using all possible resources, including your portfolio. Be prepared to answer any/all questions the network committee participants propose. Remember, you are selling both your company and your design. Design Specifications In the middle of the computer lab there are two rows of tables with five tables in each row. Each table is 15 feet long and has 4 computers. Each table is 2½ feet wide. The distance between each row of tables from front to back is 4 feet, with 4 feet between the two rows of desks. Along the walls of the lab are tables that run the entire length of the room and are 21/2 feet wide. Each table contains 5 printers. The aisles between the computer tables and the printer tables are 8 feet wide. The teacher s table at the front of the room has a computer and a printer and is located six feet from the wall and four feet from the student desks. Computer Lab There are two electrical power receptacles beneath each of the computer tables, four on the walls beneath the built-in side tables, and two on the wall behind the teacher s table. 226 ST A Internetworking Fundamentals

25 Unit 2: LAN Configurations Administration Office The administration building is 1,200 feet from the computer lab. The administration building is 30 feet by 30 feet square. There are 5 offices each 10 feet by 10 feet. The offices are placed around the perimeter of the building. The lobby is 20 feet by 20 feet. Each office will have a computer. The computer will be installed against the right outside corner of each office where there are two electrical power outlets. The printer will be placed in the lobby, 5 feet in from office number 1 where power supply receptacle is located on the wall. Teacher s Lounge/Offices The teacher s lounge/offices are 900 feet from the computer lab and 1000 feet from the administration office. It is set up exactly like the administration building offices. As part of your design proposal presentation, you must include: A list of equipment needed and the cost of this equipment, including all connectors. A graphical representation of your network design, which shows cabling location and type, transceivers, repeaters, computers, printers, and/or any other details you deem pertinent. Be sure to include distance requirements for all cable to be installed, including AUI and patch cables. You must adhere to IEEE specifications. A summary justifying your overall design choice. For example, if you used repeaters, why? Why not more? Your presentation will take place in front of the rest of the class who represent the network committee. Be prepared to answer any questions they pose. ST A 227

26 Lesson 2-4 Ethernet Standards Rubric: Suggested Evaluation Criteria and Weightings Criteria % Your Score Presentation skills, including ability to accurately field questions from network committee Complete, accurate list of all necessary equipment and the costs associated with that equipment Graphical representation showing all of the devices, cabling specifications and accurate cable lengths according to IEEE specifications Thoughtful analysis and design choice as indicated in the summary TOTAL Summary In this lesson, you learned to do the following: Identify the characteristics of the various IEEE Ethernet LANs. Compare and contrast the characteristics of the various IEEE Ethernet LANs. Describe the characteristics and functions of the components used in Ethernet networks. Build and troubleshoot an Ethernet network. Design an Ethernet network in response to a Request for Proposal (RFP). 228 ST A Internetworking Fundamentals

27 Unit 2: LAN Configurations Review Questions Name Lesson 2-4: Ethernet Standards Part A 1. In 10BASE5 Ethernet networks, what type of cable is specified? a. 500-ohm thick coaxial cable b. 50-ohm thick coaxial cable c. 500-ohm thin coaxial cable d. 50-ohm thin coaxial cable 2. In the rule, the 5 indicates what? a. Maximum number of taps b. Maximum number of cable segments c. Maximum number of repeaters d. Maximum number of cable segments that can have transceivers 3. In 10BASE2 Ethernet networks, what type of cable is specified? a. 500-ohm thick coaxial cable b. 50-ohm thick coaxial cable c. 500-ohm thin coaxial cable d. 50-ohm thin coaxial cable 4. A straight tip connector is used with which Ethernet LAN? a. 10BASE5 b. 10BASE2 c. 10BASE-T d. 100BASE-T e. 10BASE-F ST A 229

28 Lesson 2-4 Ethernet Standards 5. A BNC-T connector is used with which Ethernet type? a. 10BASE5 b. 10BASE2 c. 10BASE_T d. 100BASE-T e. 10BASE-F 6. The maximum number of devices on a 10BASE-T network is what? a. 30 b. 100 c. 500 d. 1, The maximum number of devices on a 10BASE5 network is what? a. 30 b. 100 c. 500 d. 1, What is an AUI connector? a. A 15-pin connector used with an external transceiver b. Device used only with a fan-out unit c. The standard connector used for 100BASE-T connections d. Device used for all Ethernet connections 9. A non-intrusive network tap can cause which of the following? a. The cable to be cut b. Does not cause the cable to be cut c. Causes the cable to be cut, but linked back together d. None of the above 230 ST A Internetworking Fundamentals

29 Unit 2: LAN Configurations 10. The maximum number of devices per cable segment in 10BASE-F networks is what? a. 1,024 b. 500 c. 2 d The maximum cable length for each segment in 10BASE-T networks is what? a. 100 meters b. 185 meters c. 285 meters d. 500 meters 12. A 10Base-T network may use which cable types? a. Category 3 b. Category 4 c. Category 5 d. All of the above 13. The maximum number of devices per segment on a 10BASE-F network is what? a. 30 devices b. 1,024 devices c. 2 devices d. 500 devices ST A 231

30 Lesson 2-4 Ethernet Standards 14. A fan-out unit is: a. A single transceiver which allows multiple connections to the network b. The same as a repeater c. Multiple transceivers in a box d. Provides cooling for the network 15. What is the difference between a physical bus and a logical bus/physical star topology? a. The physical bus uses a hub b. The logical bus, physical star is always used for Ethernet networks c. The logical bus, physical star uses a hub d. There is no difference 16. What is the topology of 10BASE-T networks? a. Physical bus/logical star b. Physical/logical star c. Physical/logical bus d. Physical star/logical bus 17. Which type of cabling is used to connect devices in a 10BASE-F network? a. Category 5 b. UTP c. STP d. Fiber optic 232 ST A Internetworking Fundamentals

31 Unit 2: LAN Configurations 18. The maximum number of repeaters/hubs per LAN allowed on a 10BASE-T segment is: a. 4 b. 100 c. 30 d Maximum fiber cable distances are: a. 550 meters b. 250 meters c. 2,000 feet d. 2,000 meters 20. What is a MAU? a. A transceiver b. A combination transceiver and tap c. A cable d. A NIC 21. What is an AUI? a. An external transceiver b. An internal transceiver c. A transceiver cable d. An N-type connector 22. The Ethernet rule means what? a. No more than 5 cable segments, 4 repeaters, and 3 segments with devices b. No more than 5 repeaters, 4 cable segments, and 3 segments with devices c. No more than 5 segments with devices, 4 repeaters, and 3 cable segments. d. No more than 5 devices, 4 hubs, and 3 cable segments ST A 233

32 Lesson 2-4 Ethernet Standards 23. Which cable type is used in LANs over 1,000 meters in length? a. UTS b. STP c. Category 5 d. Fiber Optic 24. Which type of Ethernet LAN uses a FOMAU transceiver? a. 10BASE5 b. 10BASE2 c. 10BASE-T d. 10BASE-F 25. Which type of copper cable is most useful when EMI and distances of more than 1,000 meters are a concern? a. UTP b. STP c. Thick coaxial d. Thin coaxial Part B Complete the chart below that compares and contrasts four different Ethernet LANs. Answer: Characteristics 10BASE5 10BASE2 10BASE-T 10BASE-F Cable type Maximum cable segment length Maximum number of cable segments 234 ST A Internetworking Fundamentals

33 Unit 2: LAN Configurations Part C Name each of the 10BASE5 components and explain their function. Name the 10BASE2 components and explain their function. Name the 10BASE-T connectors and ports and explain their function. Name the transceiver used in 10BASE-F networks and explain its function. Describe the 10BASE-F ports. How is 100BASE-T (Fast) Ethernet different from other Ethernet LANs? ST A 235

34 Lesson 2-4 Ethernet Standards Scoring Rubric: Suggested Evaluation Criteria and Weightings Criteria % Your Score Part A: Identify the characteristics of the various IEEE Ethernet LANs Part B: Compare and contrast the characteristics of the various IEEE Ethernet LANs Part C: Describe the characteristics and functions of the components used in Ethernet networks TOTAL 100 Try It Out: Configure a LAN using two hubs. 100 Stretch Yourself: Connect Ethernet hubs and ping. Network Wizards: Propose a Network Design to specifications Resources Advanced Computer Networks (1998). Networking Solutions Guide. (1998) [Online]. Available: [1999, March 1]. Aschermann, Robert (1998). MCSE Networking Essentials for Dummies. IDG Books Worldwide, Inc. Foster City, California. Bert, Glen (1998). MCSE Networking Essentials: Next Generation Training Second Edition. New Riders Publishing Indianapolis, Indiana. Casad, Joe. et al. (1997). MSCE TestPrep Networking Essentials. New Riders Publishing, Indianapolis, Indiana. Chellis, James; Perkins, Charles; & Strebe, Matthew (1997). MCSE Networking Essentials Study Guide. Sybex Inc. Alameda, California. Derfler, Jr., Frank J., & Freed, L. (1998). How Networks Work, Fourth Edition. Macmillan Computer Publishing/Que Corporation, Indianapolis, Indiana. Hayden, Matt. (1998). Sam's Teach Yourself Networking in 24 Hours. Sam's Publishing, Indianapolis, Indiana. 236 ST A Internetworking Fundamentals

35 Unit 2: LAN Configurations HDS Network Systems, Inc. (1996). IEEE Ethernet type. In System Administrator s Guide [Online]. Available: [1999, May 13]. Incorporation ( ). Topics in Networking [Online]. Available: [1999, March 21]. Lantronix. (1999). Ethernet Tutorial. In Technology Tutorials [Online]. Available: [1999, April 20]. Lowe, Doug. (1998). Networking for Dummies. Third Edition. IDG Books Worldwide, Inc., Foster City, California. Microsoft Corporation (1998). Dictionary of Computer Terms, Microsoft Press, Redmond, Washington. Nortel Networks (1998). Internetworking Fundamentals: Student Guide Bay Networks Inc. Billerica, Massachusetts. Nortel Networks (1999). NetKnowledge: Internetworking Fundamentals. Nortel Networks, Billerica, Massachusetts. Palmer, Michael J. (1998) Hands-On Networking Essentials with Projects, Course Technology, Inc. Cambridge, Massachusetts. Spurgeon, Charles E. (1997). Practical Networking With Ethernet, International Thomson Computer Press, Boston, Massachusetts. Spurgeon, Charles. ( ). Quick Reference Guide to Ethernet [Online]. University of Texas Office of Telecommunications. Available: [1999, April 20]. The Siemon Company (1997). Siemon Guidelines to Industry Standards [Online]. Available: [1999, March 3]. University of Minnesota College of Education & Human Development, Office of Information Technology. (No date). Web 66 Network Construction Set [Online]. Available: web66.umn.edu/construction/lan/lan.html [1999, February 2]. University of New Hamphsire InterOperability Labs (1997). Tutorials and Resources [Online]. Available: wwww.iol.unh.edu/ menu/ consortium.html [1999, May 13]. University of Texas Pan American, Department of Computer Science (1996). Ethernet Related Pages. In Xiannong Meng s Home Page [Online]. Available: ~meng/ ethernet.html ST A 237

36 Lesson 2-4 Ethernet Standards 238 ST A Internetworking Fundamentals