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When I was in college many years ago, my psychology professor said, “Every year, we give the same tests, but each year, the correct answers change.” We never knew if he was joking or if research really was providing new answers. But when it comes to networking options, the same phrase applies. So here in 2009, does one choose copper, fiber or wireless? Correct answers and explanations are in red.
1. The latest standardized version of Ethernet is __________.
A. Gigabit Ethernet
B. 10 gigabit Ethernet
C. 40 gigabit Ethernet
D. 100 gigabit Ethernet
The fastest version of Ethernet currently standardized is 10 Gigabit Ethernet, but 40 and 100 Gbps versions are being developed.
2. If gigabit Ethernet is the fastest network speeds planned, what category of unshielded-twisted pair (UTP) copper cable provides the minimum level of performance needed?
A. Category 5
B. Category 5e
C. Category 6
D. Category 6A
Gigabit Ethernet would not run over regular Cat 5 so an enhanced Cat 5, Category 5e, was created.
3. If 10 gigabit Ethernet is the fastest network speeds planned, what category of UTP copper cable provides the minimum level of performance needed?
A. Category 5e
B. Category 6
C. Category 6A
D. Category 7
Category 6A was developed to meet the requirements of 10 Gb Ethernet over 100 meters and is the minimum cable grade that will permit 10G use.
4. For 40 and 100 gigabit Ethernet, which categories of UTP copper cable are being considered?
A. Category 6A
B. Category 7
C. Shielded-twisted pair
D. None of the above
No UTP cables are being considered for 40–100 Gb Ethernet.
5. Today’s network backbone cabling should include __________.
A. 62.5/125 multimode fiber (OM1)
B. 50/125 multimode fiber (OM2)
C. 50/125 laser-optimized multimode fiber (OM3)
D. 50/125 laser-optimized multimode fiber (OM3) plus some single-mode fibers
The best choice for backbones is 50/125 laser-optimized multimode fiber (OM3) but adding some singlemode fibers for future use is cheap insurance.
6. Laser-optimized 50/125 multimode fiber is being enhanced for even higher bandwidth capability for 40–100 gigabit Ethernet.
Manufacturers already offer laser-optimized fibers with bandwidth of 3,500–4,000 MHz-km at 850 nm, and standards are being developed.
7. The latest and fastest version of Wi-Fi is __________.
A. IEEE 802.11b
B. IEEE 802.11g
C. IEEE 802.11n
D. IEEE 802.11x
IEEE 802.11n is the latest version of Wi-Fi and is expected to be approved late in 2009. However many vendors are already supplying equipment to the current specifications.
8. The latest standards now in development for Wi-Fi promise a maximum speed of about __________ megabits per second but a practical throughput closer to __________ megabits per second.
A. 600, 100
B. 500, 400
C. 250, 100
D. 100, 33
IEEE 802.11n uses multiple antennas to give a theoretical bandwidth of 600 Mb/s but practical throughput of the finalized standard will be more like 100 Mbps.
9. In order to provide maximum throughput, the latest versions of Wi-Fi require cabled connections to the access points of __________.
A. Fast (100 megabits per second) Ethernet
B. Gigabit Ethernet
C. 10 gigabit Ethernet
In order to support full 802.11n performance at up to 600 Mb/s, the wireless access point needs a solid Gigabit Ethernet connection.
10. The average corporate user only needs the bandwidth of the “g” version of Wi-Fi for normal applications.
100 Mbps is plenty for most users, even for streaming video needed for applications like videoconferencing.
HAYES is a VDV writer and educator and the president of The Fiber Optic Association. Find him at www.jimhayes.com.