Chapter 5 - Network Cabling

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c. Cat 5e

c. 10 Gbps

a. 802.3at

d. 40km

a. NEXT is crosstalk that occurs between wire pairs near the source of a signal.

c. coarse wavelength division multiplexing

d. The cable must be a rollover cable.

c. decibels

a. A customer modem is continuously losing signal due to large distance from the transmitting device.

b. statistical time division multiplexing

d. The materials used for shielding and conducting cores.

a. TIA/EIA 568A

c. 1, 2, 3, 6

b. 3/8 inch

c. 10GBase-T

b. Light experiences virtually no resistance when traveling through glass.

c. fiber cleaver

a. 8 degrees

d. local connector (LC)

c. SFP+ is the same size as SFP, and supports a theoretical maximum transmission speed of 16 Gbps.

c. 1300 nanometers

b. multimeter

a. A mismatched connector will have different impedance ratings, causing data errors.

c. white/orange, orange, white/green, blue, white/blue, green, white/brown, brown

a. registered jack 11 (RJ-11)

b. Power over Ethernet requires CAT6 or better copper cable.

a. wavelength division multiplexing

d. simplex

a. Jitter is what happens when packets experience varying amounts of delay and arrive out of order.

b. RG-6

A TDR issues a signal on a cable and then measures the way the signal bounces back (or reflects) to the TDR. Bad connectors, crimps, bends, short circuits, cable mismatches, bad wiring, or other defects modify the signal's amplitude before it returns to the TDR, thus changing the way it reflects. The TDR then accepts and analyzes the return signal, and based on its condition and the amount of time the signal took to return, determines cable imperfections

Bandwidth is the amount of data that could theoretically be transmitted during a given period of time. In an analogy, the bandwidth of a three-lane freeway is the number of vehicles that can pass a checkpoint in one minute when traffic is bumper-to-bumper and traveling at the maximum speed limit. In practice, that bandwidth never happens. Still, we could increase potential bandwidth by adding more lanes to the freeway. At the same time, consider that adding too many lanes for the amount of anticipated traffic, so that some lanes are never used, would be a waste of resources. Throughput is the measure of how much data is actually transmitted during a given period of time. In our analogy, throughput measures the actual traffic on the three-lane freeway that passes in one minute. Using all the available bandwidth results in more accidents and traffic jams than if bandwidth exceeds actual throughput by a little. However, this beneficial effect is limited-providing a lot more potential bandwidth than actual throughput does not achieve additional improvement in performance unless you need to account for regular spikes in traffic.

Two common sources of noise are: * EMI (electromagnetic interference)-Caused by motors, power lines, televisions, copiers, fluorescent lights, microwave ovens, manufacturing machinery, and other sources of electrical activity (including a severe thunderstorm). One type of EMI is RFI (radio frequency interference), or electromagnetic interference caused by radio waves. (Often, you'll see EMI referred to as EMI/RFI.) Strong broadcast signals from radio or TV antennas can generate RFI. * crosstalk-Occurs when a signal traveling on one wire or cable infringes on the signal traveling over an adjacent wire or cable. The resulting noise, or crosstalk, is equal to a portion of the second line's signal. If you've ever been on a traditional, landline phone and heard the conversation on a second line in the background, you have heard the effects of crosstalk.

The maximum length limitation is due primarily to optical loss, or the degradation of the light signal after it travels a certain distance away from its source (just as the light of a flashlight dims after a certain number of feet). Optical loss accrues over long distances and grows with every connection point in the fiber network. Dust or oil in a connection (for example, from people handling the fiber while splicing it) can further exacerbate optical loss

Modal bandwidth is a measure of the highest frequency of signal a multimode fiber can support over a specific distance and is measured in MHz-km. It is related to the distortion that occurs when multiple pulses of light, although issued at the same time, arrive at the end of a fiber at slightly different times. The higher the modal bandwidth, the longer a multimode fiber can carry a signal reliably.

Place the tone generator at one end of a wire using the appropriate connector. Swipe the tone locator over each of the terminations you suspect to be the other end of that wire. You can verify the location of the wire's termination when you hear the tone. Work by trial and error, guessing which termination corresponds to the wire over which you've generated a signal until the tone locator indicates the correct choice.

SMF (single mode fiber) consists of a narrow core of 8 to 10 microns in diameter. Laser-generated light travels a single path over the core, reflecting very little. Because it reflects little, the light does not disperse as the signal travels along the fiber. This continuity allows SMF to accommodate the highest bandwidths and longest distances (without requiring repeaters) of all network transmission media. MMF (multimode fiber) contains a core with a larger diameter than SMF, usually 50 or 62.5 microns, over which many pulses of light generated by a laser or LED light source travel at various angles. Signals traveling over multimode fiber experience greater attenuation than those traversing single mode fiber. Therefore, MMF is not suited to distances longer than a few kilometers. On the other hand, MMF is less expensive to install and, therefore, typically used to connect routers, switches, and servers on the backbone of a network or to connect a desktop workstation to the network.

It is usually a case on a rack where fiber cables converge, connect with each other, and connect with fiber optic terminal equipment from the ISP. Splices at the FDP (or elsewhere on the network) might be accomplished by joining two fiber cables in a permanent bond, or various connectors might be used to create temporary splices. The transition between single mode fiber and multimode fiber cabling might also occur at an FDP.

Shapes and polishes currently used on SMF ferrules to reduce back reflection include: * UPC (Ultra Polished Connector)-Extensive polishing of the tips creates a rounded surface on a UPC (Ultra Polished Connector), which allows the two internal fibers to meet and increases efficiency over older types of connections. * APC (Angle Polished Connector)-The latest advancement in ferrule technology uses the principles of reflection to its advantage. The APC (Angle Polished Connector) still uses a polished curved surface, but the end faces are placed at an angle to each other. The industry standard for this angle is 8 degrees.

Newer transceivers that have made the GBIC obsolete include: * SFP (small form-factor pluggable)-Provides the same function as GBICs and is more compact, allowing more ports per linear inch. Also known as mini GBICs or SFP GBICs. Typically used for 1 Gbps connections, but theoretically capable of 5 Gbps. * XFP (10 Gigabit small form-factor pluggable)-Supports up to 10 Gbps and is slightly larger than SFP with lower power consumption than SFP+. * SFP+-Developed later than XFP and is the same module size as SFP; theoretical maximum transmission speed is 16 Gbps. * QSFP (quad small form-factor pluggable)-Complies with the 802.3ba standard, squeezing four channels in a single transceiver and supporting data rates up to 40 Gbps (4 x 10 Gbps). * QSFP+-Generally the same technology as QSFP while supporting data rates over 40 Gbps. Highest speed format currently is QSFP28 with a total theoretical maximum data rate of 112 Gbps (4 x 28 Gbps). * CFP (centum form-factor pluggable)-Intended for 100-Gbps network connections, with each succeeding generation (CFP, CFP2, CFP4) becoming smaller and more energy-efficient. Centum is Latin for 100.