The four speeds of Ethernet networks described in Chapter 5 are 100 megabit, 1 gigabit, 10 gigabit, and 100 gigabit.

True / False Questions
 

31. (p. 91) All versions of Ethernet use either a hub or a switch.
TRUE

32. (p. 91) The four speeds of Ethernet networks described in Chapter 5 are 100 megabit, 1 gigabit, 10 gigabit, and 100 gigabit.
FALSE

33. (p. 100) Ethernet backbone networks must use a high-speed switch.
TRUE

34. (p. 94) A full-duplex Ethernet device can simultaneously send and receive data.
TRUE

35. (p. 94) 1000BaseT connections and ports look exactly like the ones on a 10BaseT or 100BaseT network.
TRUE

36. (p. 95) 1000BaseSX devices do not physically resemble 100BaseFX products.
FALSE

37. (p. 95) 1000BaseLX connectors look like 1000BaseSX connectors.
TRUE

38. (p. 94) You should always use the operating system to force the full-duplex setting on a NIC.
FALSE

39. (p. 95) The Ethernet folks are trying to position 1000BaseSX as the Ethernet backbone of the future.
FALSE

40. (p. 96) Small Form Factor (SFF) connectors solve the manufacturers' problem of needing more space for ports on network devices for fiber-optic cabling.
TRUE

Fill in the Blank Questions
 

41. (p. 93) While 10- and 100-megabit Ethernet may use a hub, Gigabit and 10 Gigabit Ethernet networks must use a(n) __________________.
switch

42. (p. 91) Every UTP version of Ethernet has the same maximum distance from the switch or hub to the nodes of __________________.
100 meters

43. (p. 91) When developing the various new standards beyond 10BaseT, the 802.3 committee made sure they made no changes to the Ethernet __________________, so that, as long as there is a way to handle the speed and hardware differences, the various Ethernet technologies could interconnect and transmit usable data.
frames

44. (p. 93) The 100-Mbps Ethernet standard that uses fiber-optic cable is called _____________.
100BaseFX

45. (p. 94) When a network has switches and NICs operating at different speeds, a feature in the switches and NICs called _________________ determines the speed of the communications, as well as whether the NIC and switch will communicate in half duplex or full duplex.
auto-negotiation

46. (p. 94) All modern NICs are __________________ and __________________.
multispeed; auto-sending

47. (p. 94) The need for network speed in the late 1990s resulted in the IEEE developing a group of standards known as __________________, now the most common type of Ethernet found on new NICs.
Gigabit Ethernet

48. (p. 94) IEEE approved two different versions of Gigabit Ethernet, __________________ and __________________.
1000BaseT; 1000BaseX

49. (p. 96) 1000BaseT achieves gigabit performance using __________________ cabling.
four-pair UTP

50. (p. 94) The Gigabit Ethernet standard 1000BaseX divides further into other standards, three of which are __________________, __________________, and __________________.
1000BaseCX; 1000BaseSC; 1000BaseLX

51. (p. 94) The predominant Gigabit Ethernet standard is __________________.
1000BaseT

52. (p. 95) Of the three 1000BaseX standards discussed in the chapter, only __________________ uses a type of copper cabling; the other two use fiber-optic cabling.
1000BaseCX

53. (p. 95) Of the fiber-based 1000BaseX standards discussed in the chapter, __________________ is designed for use in LANs, and __________________ is designed for WANS.
1000BaseSX, 1000BaseLX

54. (p. 96) The most popular fiber-optic connector is the _____________.
SC

55. (p. 91) A 100BaseT network uses a(n) __________________ signal type.
baseband

56. (p. 93) A 100BaseFX network uses a(n) __________________ signal type.
baseband

57. (p. 93) A 100BaseFX network has a maximum distance of __________________.
2 kilometers

58. (p. 96) Of the several Gigabit Ethernet standards discussed in the chapter, only __________________ uses RJ-45 connectors.
1000BaseT

59. (p. 96) 1000Base SX networks use __________________ fiber-optic cable.
multimode

60. (p. 96) 1000BaseSX has a maximum length of __________________.
220 to 500 meters

61. (p. 91) Both 100BaseT and 100BaseFX are referred to as __________________, although this term is not used for newer, faster Ethernet standards.
Falseast Ethernet

62. (p. 96) 1000BaseLX has a maximum length of __________________.
5 kilometers

63. (p. 91) Theoretically, an Ethernet hub or switch cannot have more than __________________ nodes.
1024

64. (p. 96) 1000BaseLX networks use a variety of connectors, but __________________ and __________________ are common.
LC, SC

65. (p. 96) 1000BaseSX cabling has a(n) __________________ wavelength.
850 nm

66. (p. 95) 1000BaseSX cabling uses a(n) __________________ to transmit light.
LED

67. (p. 100) In order to get the fastest network response while keeping costs down, network techs will create a(n) ___________________ network.
multispeed

68. (p. 100) A multispeed network installed in a large building is likely to have a separate __________________ on each floor of the building.
Ethernet switch

69. (p. 91) The IEEE supports two kinds of 100BaseT networks, the ____________ and the ______________ standards.
100BaseTX; 100BaseT4

70. (p. 100) Ethernet switches can also connect segments to a _________________ that usually runs at a higher speed than the segments it connects.
backbone

Essay Questions
 

71. (p. 92) What is the major advantage of using multispeed devices such as 10/100BaseT NICs and switches/hubs on the same network? Include a short description of how they behave when connected to similar devices and when connected to slower devices. 

A 10/100BaseT device automatically functions as a 100BaseT device when plugged into another 10/100BaseT or 100BaseT device, but will function as a 10BaseT device when plugged into another 10BaseT device. This makes it easy for an organization to introduce 100BaseT devices as needed, rather than having to upgrade the entire network at once.

72. (p. 91) Provide an overall statement about the types of cabling found in all versions of Ethernet. 

With rare exceptions, every version of Ethernet uses either unshielded twisted pair (UTP) or fiber-optic cable.

73. (p. 91) Explain why it is significant that the IEEE 802.3 committee decided to make no changes to the actual Ethernet frames when developing faster cabling standards. 

By not changing the actual Ethernet frames when they developed new Ethernet cabling standards, the IEEE 802.3 committee ensured that different speeds of Ethernet could interconnect, as long as there was a way to handle the differences in speed and cabling.

74. (p. 91) Why did two 100-megabit UTP Ethernet standards emerge at the end of the 1990s? 

The answer to why two 100-megabit UTP Ethernet standards emerged is the quest for competitive advantage. Different manufacturers came out supporting different standards, hoping that if theirs became the predominant one, they would gain an edge over the competition by having an inside line on making the hardware that supports the standard.

75. (p. 92) Explain how to distinguish a 10BaseT NIC from a 100BaseT NIC. 

It is difficult to tell the difference between a 10BaseT NIC and a 100BaseT NIC. The connector will not be any help, since both use RJ-45 connectors. You must inspect the NIC (and its documentation) closely, looking for such clues as a model name on the card, explanation in the documentation, or extra indicator lights to show the speed. If physical inspection fails to give you the answer, install the card and see what the OS knows about it. For instance, if a card has a device driver installed, Windows Device Manager should give a name, which is often descriptive of the speed of the NIC.

76. (p. 92) You are in the process of upgrading a network from 100-megabit Ethernet to Gigabit Ethernet. Explain what you will need to do when you connect a computer with a 100-megabit/Gigabit Ethernet NIC to a 100-megabit/Gigabit switch. 

The answer is that you should not normally need to do anything special. The switch and NIC will auto-negotiate and communicate in Gigabit mode.

77. (p. 93) Explain the major improvement that 100BaseFX provides over the 10BaseFL standard. 

The major improvement is speed. The 100BaseFX standard supports a maximum speed of 100 Mbps, while the 10BaseFL standard operates at 10 Mbps.

78. (p. 95) Explain briefly how to extend the 1000BaseLX maximum distance of 5 kilometers. 

You can extend the maximum distance of 5 kilometers for 1000BaseLX networks up to 70 kilometers by using special repeaters.

79. (p. 94) Compare and contrast 1000BaseT to earlier UTP versions of Ethernet. 

1000BaseT offers 1-gigabit speed, while the earlier versions, 10BaseT and 100BaseT, offered 10-megabit and 100-megabit speeds respectively. The 1000BaseT connections and ports look exactly like those of the slower UTP standards.

80. (p. 95) Describe what makes 1000BaseCX unique among the Gigabit Ethernet standards. 

The 1000BaseCX standard is unique in the cabling it uses, which is shielded 150-Ohm twinaxial copper cable with a length limit of 25 meters. 1000BaseCX has made little progress in the Gigabit Ethernet market.

81. (p. 95) Describe the cabling used for 1000BaseSX standard. Include the length limits, signaling, and wavelength. 

The 1000BaseSX standard uses multimode fiber-optic cabling using a 850-nm wavelength LED and having a maximum cable length of 220 to 500 meters, depending on the manufacturer of the equipment.

82. (p. 92) Explain which three components must be replaced when upgrading a 10BaseT network to the 100BaseT standard. 

The three network components that must be replaced when upgrading a 10BaseT network to the 100BaseT standard are the NICs, the cabling, and the hub/switch. The NICs and hub or switch must support 100BaseT, and may be replaced with multispeed devices, while the cabling must be CAT 5 or better. The cabling may not be an issue, since CAT 5 has been the preferred minimum cable for many years.

83. (p. 93) What does half duplex mean? 

In half-duplex mode, communication can take place in either direction, but only in one direction at a time. In other words, the device can either send or receive, but it cannot do both simultaneously.

84. (p. 96) Briefly discuss the two Small Form Factor (SFF) connectors described in the chapter. 

The two SFF connectors described in the chapter are the Mechanical Transfer Registered Jack (MT-RJ) and the Local Connector (LC). The MT-RJ gained popularity early on with important companies like Cisco, while the LC connector is very popular, particularly in the United States. Fiber experts consider the LC connector to be the predominant fiber connector.

85. (p. 96) Explain why fiber equipment may have different connectors—even nonstandard ones. 

The reason fiber equipment may have different types of connectors is because the fiber industry has no standard for connectors beyond ST and SC. Therefore, different makers of fiber equipment create their own connectors.

86. (p. 97) Define a GBIC. 

A GBIC is a gigabit interface converter, a module that is plugged into a Gigabit Ethernet switch or other hardware to accommodate the connector type required for the connection.

87. (p. 99) How is 10 Gigabit Ethernet (10 GbE) presently used, and what can be expected in the future? 

Presently 10 Gigabit Ethernet is more of a WAN or high-level LAN network. In the future, if this group of standards follows the evolution of the previous Ethernet standards, it will trickle down to the desktops.

88. (p. 97) Explain why over time, there is a trend toward fewer standards to support a specific technology 

In the beginning many standards may come into existence for a new technology because manufacturers desire to have the standard for a new technology. However, over time, only one or a few standards for a specific technology will be widely supported, and the others will fall by the wayside.

89. (p. 97) The IEEE created many 10 GbE standards. Discuss the general differences in these standards without giving specific names to the standards. 

The IEE created several 10 GbE standards that could use traditional LAN Physical layer mechanisms, plus standards that could take advantage of the SONET infrastructure and run over WAN fiber. They also recognized the need for different networking situations, such as long-distance transmissions over single-mode fiber versus transmissions across short distances via multimode fiber.

90. (p. 97) Discuss the factors defined in the 10 GbE standards without giving specific names of the standards and their parameters. 

Among the factors defined in the 10 GbE standards are fiber cabling versus copper cabling (the latter is newer) and among the fiber standards, the type of fiber used, the wavelength of the laser or lasers, and the Physical layer signaling type. These factors in turn define the maximum signal distance.

91. (p. 98) Briefly explain the difference between the designations "S," "L," and "E" in the standards 10GBaseSR, 10GBaseLR, and 10GBaseER. 

The "S" in 10GBaseSR stands for short-wavelength (850 nm) signal. The "L" in 10GBaseLR stands for long-wavelength (1310 nm) signal. The "E" in 10GBaseER stands for extra-long-wavelength (1550 nm) signal.

92. (p. 98) Both the 10GBaseSR and 10GBaseSW standards have a wide range of signal length—26 to 300 meters. Briefly explain what affects signal length for these two standards. 

The signal length of the 10GBaseSR and 10GBaseSW standards is affected by the type of multimode fiber used.

93. (p. 98) Describe the characteristics of the 10GBaseEW standard, including fiber type, wavelength, physical layer signaling, and maximum signal length. 

The 10GBaseEW standard uses single-mode fiber, has a wavelength of 1550 nm, uses SONET/WAN physical layer signaling, and has a maximum signal length of 40 km.

94. (p. 99) Describe what all types of 10 GbE equipment have in common, and how they may physically differ. 

All types of 10 GbE equipment send and receive the exact same signal, but the physical medium varies.

95. (p. 100) Describe a network backbone. 

A network backbone is a series of high-speed (relative to the rest of the network) switches that in turn connect to other switches that connect to other, slower network segments. The network backbone does not usually connect directly to computers, other than possibly to servers.

96. (p. 100) What are the benefits of a multispeed network? 

The purpose of a multispeed network (one with a backbone) is to provide the fastest network speed, while keeping costs down. Rather than have the entire network operate at a higher speed with very expensive equipment, a multispeed network uses a high-speed backbone to connect other network segments.

97. (p. 98) Briefly describe the x and y code in the 10GBasexy naming convention. 

In the 10GBasexy naming convention for 10 Gigabit Ethernet, the x represents the type of fiber and the wavelength of the laser signal, while the y represents either LAN-based signaling ("R") or WAN-based signaling ("W"). Therefore, the 10GBaseSR standard represents short-wavelength (850 nm) over multimode fiber and with LAN-based signaling.

98. (p. 98-99) Compare 10GBaseT to earlier, slower versions of UTP Ethernet. 

While 10GBaseT looks and works like the slower versions of UTP Ethernet, it runs at a much higher speed. The downside is that 10GBaseT running on CAT 6 has a maximum cable length of only 55 meters, but if run on the updated CAT 6a standard, 10GBaseT will run at the standard UTP Ethernet distance of 100 meters.

99. (p. 99) Describe multisource agreements (MSA), including where it is used in a network, and why it is needed. 

A multisource agreement (MSA) is a modular transceiver that you plug into a 10 GbE network device to convert from one media type to another. You need it because there are so many cabling and connector options in use for 10 GbE networks that devices must be able to accommodate any that are required for connectivity.

100. (p. 100) What is required on switches that connect segments of different speeds? 

Switches that connect network segments of different speeds must have separate, dedicated, high-speed ports, which run directly to the high-speed backbone switch.