Networking Essentials - Chapter 2 Exam

What is the difference between "straight" and "cross-connected" input ports?

*"Straight" =Tx----Tx Rx----Rx. "Crossed"= Tx----Rx Rx----Tx.*

*A NEXT measurement of 59.5 dB is made on wire pairs 1-2/3-6. A next measurement of 51.8 dB is made on wire pairs 3-6/7-8. Which cable pairs have the best measure NEXT performance?*

*1-2/3-6. A high NEXT (dB) value is desirable.*

Identify the six subsystems of a structured cabling system.

*1. Building Entrance* *2. Equipment Room* *3. Backbone Cabling* *4. Telecommunications Closet* *5. Horizontal Cabling* *6. Work Area*

What is the data rate for Ethernet?

*10 Mbps*

What is the data rate for FastEthernet?

*100 Mbps*

What is the over all length limitation of an individual cable run from the telecommunications closet to a networking device in the work area?

*100 Meters*

What is the data rate for gigabit Ethernet?

*1000 Mbps*

How many wire pairs are in a CAT6 twisted-pair cable?

*4 Pairs*

How many pins does an RJ-45 modular plug have?

*8 Pins*

How many wires are in a CAT6 twisted-pair cable?

*8 wires*

What is 8P8C, and what connector type is most associated with this?

*8P8C (8 pin 8 connector); the RJ-45 plug and jack are the most common connectors.*

A general rule of thumb is to allow how many meters for the cable run from the telecommunications closet to the work area?

*90 Meters*

Define Power-Sum measurements.

*All four-wire pairs are used to obtain a combined performance measurement.*

Define propagation delay.

*Amount of time it takes a signal to propagate from one end of the cable to another.*

Define Alien Crosstalk

*Basically this is an unwanted signal coupling from one four-pair cable to another.*

What is the difference in CAT 5 and CAT 5e?

*CAT5e is an enhanced cable capable of carrying data at a rate of 1000 Mbps.* *CAT5 is only good for 100 Mbps.*

What are the three parts of the EIA/TIA 568B standard?

*EIA/TIA-568-B.1 Commercial Cabling Standard* *EIA/TIA-568-B.2 Twisted-pair Media* *EIA/TIA-568-B.3 Optics Fiber Cabling Standard*

2. What do EIA and TIA stand for?

*EIA: Electronics Industries Alliance.* *TIA: Telecommunication Industry Association.*

What improvements will CAT6 and CAT7 cable provide?

*Each provides improved bandwidth, which leads to improved data rates.*

A full channel test tests all the link elements from the computer through the patch panel to the wall plate. True or False?

*False*

NEXT stands for Near End Cross Talk and a low dB value is desirable. True or False?

*False*

Patch cables are too short to be tested. True or False?

*False*

The following is the color map and pin numbers for T568A: Pin# Wirecolor 1 White-Green 2 Blue 3 White-Orange 4 Green 5 White-Blue 6 Orange 7 White-Brown 8 Brown True or False?

*False*

The six subsystems of a structured cabling system are the following: Building Entrance Equipment Room Backbone Cabling Telecommunications Closet Vertical Cabling Work Area True or False?

*False*

Why are power-sum measurements critical for high-speed data communicationbover UTP?

*High-speed data communications (e.g., gigabit) requires the use of all fourwire pairs, hence the need to obtain the combined performance measurement of all four-wire pairs.*

Which subsystem does permanent networking cabling within a building belong to?

*Horizontal Cabling*

Why is delay skew critical?

*If the wire lengths of different wire pairs are significantly different, then the data on each wire will arrive at the receiver at a different time, potentially creating distortion of the data.*

What does an "X" on the input to a hub represent?

*Indicates this is a cross-connected input.*

What is a cross-connect?

*It is a space where one or more cables connect to one or more cables or equipment.*

What is the main cross-connect?

*It is the point that usually connects two or more buildings.*

The expected + loss of a 20m UTP cable should be (greater than or less than) a 90 meter UTP cable?

*Less than*

The Telco and the ISP usually connect to what room in the campus network hierarchy?

*Main cross-connect (MC)*

Signals travel in a cable at some percentage of the velocity of light. What is the term for this?

*NVP: nominal velocity of propagation.*

Define the term NEXT and what it measures

*Near End Crosstalk: A measure of the level of crosstalk within the cable.*

In regards to a CAT6 cable, what pin numbers in an RJ-45 connecter are used to carry data in a FastEthernet network?

*TX(+)* *TX(-)* *RX(+)* *RX(-)*

Which cable, UTP or STP, is preferred by the industry?

*Testing shows little performance improvement using STP. The additional cable and installation cost do not justify its use in all cases; therefore, the industry usually recommends the use of UTP cable. However, this can change with higher data rates such as 10G.*

Define a UTP full channel test.

*Tests all the link elements from the hub or switch through the path panel to the wall plate.*

Define a UTP link test.

*Tests the cable from one cable termination to another.*

Why is balance an issue in UTP cables, and what is TCL?

*The balance or symmetry of the signal over the wire pairs helps to minimize unwanted leakage of the signal when transmitting gigabit data rates. TCL is Transverse Conversion Loss, and it measures the differential output signal given a common-mode signal on the input.*

What is the limit on the bend radius for a UTP cable, and why is this important?

*The limit is four times the diameter of the cable, and bends exceeding this can introduce attenuation loss.*

*Define margin (dB) relative to cable measurements. What does it mean if the margin lists a negative value?*

*The margin indicates how many dB the measured value exceeds the limit. A negative value indicates the measurement is less than the limit.*

What is a benefit of using shielded twisted-pair cabling?

*The shield reduces the potential for electromagnetic interference.*

What is F/UTP, and what is its purpose?

*This is foil over twisted-pair cabling, and it provides improved security and noise immunity.*

What is the purpose of a lacing tool?

*This is used to properly align the wires for 568A/B and to make sure the untwisted wire is kept to a minimum.*

Define the term cross-connected input.

*Transmit and receive pairs are internally swapped to maintain proper alignment of the TX and RX pairs.*

Signals travel in a cable at some percentage of the velocity of light. The term for this is called the nominal velocity of propagation. True or False?

*True*

The following is the color map and pin numbers for T568B: Pin# Wirecolor 1 White-Orange 2 Orange 3 White-Green 4 Blue 5 White-Blue 6 Green 7 White-Brown 8 Brown True or False?

*True*

What is the difference between T568A and T568B?

*Two different standards for wiring modular connectors.*

What is the WO, and what is its purpose?

*Workstation (WO): Outlet is the termination for the horizontal cross-connect.*

Is a high PSNEXT measurement desirable?

*Yes, this indicates better cable performance.*

Which of the following best defines horizontal cabling? a. Cabling that extends out from the telecommunications closet into the LAN work area. b. Cabling that extends out from the work area into the LAN. c. Cabling that extends out from the backbone into the LAN work area. d. Cabling that extends out from the equipment room into the LAN work area. e. None of these answers is correct

*a. Cabling that extends out from the telecommunications closet into the LAN work area.*

The patch cable from a computer typically terminates into which of the following? a. Jack in a wall plate b. BNC connector c. Thin net d. RJ-11 modular plug e. RG-59

*a. Jack in a wall plate*

Horizontal cabling consists of which of the following basic blocks? (Select two.) a. Switch or hub b. Routers c. Backbone cabling d. Patch panel

*a. Switch or hub* *d. Patch panel*

63. A UTP Certification report lists the following. Pairs 12 36 45 78 Length ! 310 308 ! 311 307 What do these results indicate? Select the correct answer. a. The cable fails the certification test. b. Pairs 36 78 will be certified. c. Pairs 1245 will be certified. d. The cable has passed the certification test. e. The ! sign indicates the cable pair meets or exceeds Power Sum test criteria.

*a. The cable fails the certification test.*

55. A NEXT measurement of 59.5 dB is made on wire pairs 1-2/3-6. A NEXT measurement of 51.8 dB is made on wire pairs 3-6/7-8. Pairs 3-6/7-8 have the best NEXT performance measurement. a. True b. False

*a. True*

Delay skew is critical because if the wire lengths of different wire pairs are significantly different, the data will arrive at the receiver at a different time potentially creating distortion of the data. a. True b. False

*a. True*

In regards to CAT5e / CAT6 cable operating at half-duplex mode for Ethernet or FastEthernet, pins 1/2 3/6 are used to carry the data. a. True b. False

*a. True*

What is the overall length limitation of a UTP cable run from the telecommunications closet to a networking device in the work area? a. 10 meters b. 100 meters c. 10K meters d. 100K meters

*b. 100 meters*

What is the data rate for FastEthernet? a. 10Mbps b. 100Mbps c. 1000Mbps d. 10Kbps e. None of these answers is correct

*b. 100Mbps*

How many wires are in a CAT5e/6 twisted-pair cable? a. 12 wires b. 8 wires c. 4 wires d. 6 wires

*b. 8 wires*

The term for unwanted signal coupling from one permanent link to another is: a. Near-end crosstalk b. Alien Crosstalk c. Far-end crosstalk d. None of these answers is correct.

*b. Alien Crosstalk*

What is the benefit of shielded twisted-pair cable? a. Ease of installation b. Excellent EMI protection c. Less expensive d. Preferred by industry for all installations e. None of these answers is correct.

*b. Excellent EMI protection*

A CAT5e / 6 link test, tests from one termination to another. a. True b. False

*b. False*

Only two wire-pairs are used to obtain a proper Power Sum measurement. a. True b. False

*b. False*

A data problem is reported to the network administrator. The problem is found to be with the UTP network connection. What steps could the network administrator have taken to isolate the problem? (Select two.) a. Visually inspect all UTP terminations. b. Run a cable test using a cable tester. c. Use the ping command to verify network connectivity. d. Use pairs 4/5 7/8 to repair the connection. e. Contact the installer of the UTP cable to obtain a certification report

*b. Run a cable test using a cable tester.* *c. Use the ping command to verify network connectivity.*

A data problem is reported to the network administrator. The problem is found to be with the UTP network connection. Which steps could the network administrator have taken to isolate the problem? (Select two.) a. Visually inspect all UTP terminations. b. Run a cable test using a cable tester. c. Use the ping command to verify network connectivity. d. Use pairs 4/5 7/8 to repair the connection. e. Contact the installer of the UTP cable to obtain a certification report.

*b. Run a cable test using a cable tester.* *c. Use the ping command to verify network connectivity.*

How many pins does an RJ-45 modular plug have? a. 4 b. 6 c. 8 d. 16 e. None of these answers is correct.

*c. 8*

10GBASE-T requires the use of which of the following in the transmission of data over UTP? a. The high data lines b. Pins 4/5 7/8 only c. All four wire pairs d. 10G is not possible at 10G

*c. All four wire pairs*

What is an 8P8C connector? a. Another term for an RJ-11 connector b. Another term for an RJ-6 connector c. Another term for an RJ-45 connector d. Another term for RS-232

*c. Another term for an RJ-45 connector*

The length difference in wire pairs for UTP a. indicate the cable should not be certified. b. indicate the cable should be certified. c. is due to the difference in the cable twists for each wire pair. d. is due to poorly manufactured cable.

*c. is due to the difference in the cable twists for each wire pair.*

What type of cable is currently recommended for LAN work areas? a. Shielded twisted-pair b. CAT6 shielded twisted-pair c. CAT 5e UTP d. CAT6 UTP e. CAT7 UTP

*d. CAT6 UTP*

Which does permanent networking cabling within a building belong to? a. Vertical Cabling b. Work Area c. Equipment Room d. None of these answers is correct.

*d. None of these answers is correct.*

A UTP Certification report lists the following. Pairs 12 36 45 78 Length 285 288 284 283 What do these results indicate? Select the correct answer. a. The test must be repeated. b. Insufficient information to obtain an answer. c. The cable length is too long. d. The cable passes the length test

*d. The cable passes the length test.*

A UTP certification report lists the following. Pairs 12 36 45 78 Length 285 288 284 283 What do these results indicate? a. The test must be repeated. b. Insufficient information to obtain an answer. c. The cable length is too long. d. The cable passes the length test

*d. The cable passes the length test.*