Ch.5 - Network Cabling

EOP (Ethernet Over Power)

An Ethernet LAN connection implemented over the electrical wiring in a building using a pair of power-line adapters, one at each end of the connection, that plug into power outlets. - transferring data through power cables - good for old buildings and places that lack internet/Ethernet cabling but have power outlets - data is shared on the same line, is NOT secure (can't be encrypted)

cable continuity tester

An instrument that tests whether voltage (or light, in the case of fiber-optic cable) issued at one end of a cable can be detected at the opposite end of the cable. Also called cable checker or cable tester. - battery operated and has two parts: - base unit connects to on end of cable and generates voltage - remote unit connects to one end of the cable and detects voltage - some can inform you if cables in UTP/STP are correctly following TIA/EIA 568 standards - certain kinds test for certain networks, such as 100BaseT or 1000BaseT Ethernet - DO NOT USE ON LIVE NETWORK WIRE

Cat 3 (Category 3)

An outdated form of UTP that contained four wire pairs and could carry up to 10 Mbps, with a possible bandwidth of 16 MHz. - used for 10 Mbps ethernet or 4 Mbps token ring networks - rarely used today

short circuit

An unwanted connection, such as when exposed wires touch each other.

minimum cable standard for gigabit Ethernet

CAT 5e

fiber optic cable

Cable that uses light guided through thin glass tubes, instead of electrical signals, to transmit data. It is very fast but also expensive. - has a central core that transfers pulsating light sent from one of two sources: - laser: intense, focused light travelling extremely long distances with high throughput - LED: cool burning, long lasting technology used on shorter cable connections - each strand in glass fiber transmits only in one direction (simplex) - requires two strands for full duplex communications

physical media used for 100Base-T (fast ethernet) Ethernet

Cat 5 or better

physical media used for 1000Base-T (gigabit Ethernet) Ethernet

Cat 5 or better (Cat 5e preferred)

physical media used for 10GBase-T (10 gigabit Ethernet) Ethernet

Cat 6a or Cat 7 (Cat 7 preferred)

SMF connectors

Classified by size and shape of the ferrule (extended tip of connector that makes contact with receptacle in jack or other connector) - designed to reduce back reflection: return of light signal back into fiber that is transmitting the signal - measured in optical loss in decibels (dB)

UTP (Unshielded Twisted Pair) cable

Common twisted-pair cable without shielding. Compare to STP. - one or more insulated wire pairs encased in plastic sheath - less expensive than STP - less resistant to noise than STP - more popular than STP due to cost

FEXT (far end crosstalk)

Crosstalk measured at the far end of the cable from the signal source.

NEXT (near end crosstalk)

Crosstalk that occurs between wire pairs near the source of a signal. - sometimes caused by an improper cable termination

probe

(1) a repeated trial message transmitted by tracert and traceroute utilities to trigger routers along a route to return specific information about the route (2) small electronic device that emits a tone when it detects electrical activity on a wire pair. when used with tone generator, can help locate termination of wire pair (3) 802.11 wireless networking, a type of frame issued by a station during active scanning to find nearby access points

jitter

A transmission flaw caused by packets experiencing varying amounts of delay and arriving out of order. Also called PDV (packet delay variation). - might cause streaming video or voice transmissions to pause repeatedly, jump around, or stall out completely - is an aspect of latency

bidirectional

A transmission method that allows each fiber cable to carry data in both directions. - full duplexing obtained with just one cable instead of the usual two for fiber optic

loopback adapter

A troubleshooting tool that plugs into a port (for example, an RJ-45 or fiber-optic port) and crosses the transmit line with the receive line, allowing outgoing signals to be redirected back into the computer for testing. Also called a loopback plug. - tests ports or cables for connectivity - directly into port = tests for bad port - cable connector into loopback jack = testing to cable continuity

1,000,000,000 bits per second (billion)

1 Gbps (giga)

1,000,000 bits per second (million)

1 Mbps (mega)

1,000,000,000,000 bits per second (trillion)

1 Tbps (tera)

1 bit per second

1 bps

1000 bits per second

1 kbps (kilo)

what are the 3 common fiber cable problems?

1. type mismatch: different cable types will not successfully connect, different core sizes will not work (even with same cable type), and different connectors will not connect 2. wavelength mismatch: different fiber cables use different wavelengths for transmission 3. dirty connectors: signal loss can occur if fiber connectors get even a little dirty - optical loss occurs and other errors can follow

10GBase-T (10-Gigabit Ethernet) maximum transmission speed (Mbps)

10,000 Mbps

100Base-T (fast ethernet) maximum transmission speed (Mbps)

100 Mbps

What is the maximum distance per segment of 100Base-T (fast ethernet), 1000Base-T (Gigabit Ethernet), and 10GBase-T (10-Gigabit Ethernet) cables?

100 m 328 ft

1000Base-T (Gigabit Ethernet) maximum transmission speed (Mbps)

1000 Mbps

maximum segment length for STP and UTP cables

100m, or 328 ft - on ethernet networks that support data rates from 1 Mbps to 10 Gbps

fastest Ethernet standard

10GBase-T Ethernet (10 gigabit)

industry standard for APC (angle polished connector) angle used on SMF connectors

8 degrees

F-connector

A connector used to terminate coaxial cable that transmits television and cable broadband signals. - attached so pin in center of connector is conducting core f cable - cable must maintain solid metal core - most often used with RG-6 cables - after being attached to cable, connectors are screwed on like a nut and bolt assembly

SC (subscriber connector or standard connector)

A connector with a 2.5-mm ferrule that is used with single-mode, fiber-optic cable. - can have UPC or APC polish - can be full duplex

ST (straight tip)

A connector with a 2.5-mm ferrule that is used with single-mode, fiber-optic cable. - uses UPC polish - does not have full duplex

LED (light-emitting diode)

A cool-burning, longlasting technology that creates light by the release of photons as electrons move through a semiconductor material.

FDP (fiber distribution panel)

A device on a rack where fiber cables converge, connect with each other, and connect with fiber-optic terminal equipment from the ISP. - transition between SMF and MMF may occur here -

PoE injector

A device that adds power to an Ethernet cable so the cable can provide power to a device. - PoE adapter that supplies power to network equipment that demands PoE

cable performance tester

A troubleshooting tool that tests cables for continuity, but can also measure crosstalk, attenuation, and impedance; identify the location of faults; and store or print cable testing results. Also called line tester, certifier, or network tester. - does most of the functions of cable continuity tester - measures distance to connectivity device, termination point, or damaged cable - measure NEXT, alien crosstalk - ISSUES PASS/FAIL RATINGS FOR CAT CABLE STANDARDS

PoE+

A method of delivering more current (up to 25.5 watts) than PoE does to devices using Ethernet connection cables. - useful for nodes located far from traditional power receptacles or need constant, reliable power source - enough power to supply a WAP, IP phone, or wall mounted security camera - requires CAT 5 or better copper cable - power sourcing equipment (PSE) must be rated to support this technology - powered device (PDs) must also be rated to receive this technology

Cat 6 (Category 6)

A twisted-pair cable that contains four wire pairs, each wrapped in foil insulation. Additional foil insulation can cover the bundle of wire pairs, and a fire-resistant plastic sheath might cover the second foil layer. - The foil insulation provides excellent resistance to crosstalk and enables it to support a signaling rate of 250 MHz and throughput up to 10 Gbps. - includes plastic core to prevent crosstalk btw twisted pairs

Cat 7 (Category 7)

A twisted-pair cable that contains multiple wire pairs, each separately shielded then surrounded by another layer of shielding within the jacket. - supports up to 10 Gbps or signal rate of 600 MHz - supports hgiher frequencies due to wire pairs being wrapped in own shielding then packaged with more shielding beneath sheath - requires more sophisticated connectors - its larger, less flexible, and less common than other versions

PoE (Power over Ethernet)

A method of delivering up to 15.4 watts to devices using Ethernet connection cables. - useful for nodes located far from traditional power receptacles or need constant, reliable power source - enough power to supply a WAP, IP phone, or wall mounted security camera - requires CAT 5 or better copper cable - power sourcing equipment (PSE) must be rated to support this technology - powered device (PDs) must also be rated to receive this technology for for CCTV and security cameras

TDM (time division multiplexing)

A method of multiplexing that assigns a time slot in the flow of communications to every node on the network and, in that time slot, carries data from that node. - divides channel into multiple intervals of time, or time slots - time slots reserved for designated node - inefficient if some nodes on network rarely send data - type of multiplexing used on copper lines

crossover cable

A twisted-pair patch cable in which the termination locations of the transmit and receive wires on one end of the cable are reversed as compared with the other end. - legacy networking cable for networking devices that do not support gigabit ethernet - solved problem of connecting like devices who were transmitting and receiving on same wires - modern devices today have auto-sense function enabling them to detect way wires are terminated in plug and then adapt transmit and receive signalling accordingly rendering this cable obsolete - reverses transmit and receive wire pairs

tone locator

A small electronic device that emits a tone when it detects electrical activity on a wire pair. When used in conjunction with a tone generator, it can help locate the termination of a wire pair. Also called a probe. - ONLY TELLS YOU WHERE WIRE/CABLE TERMINATES

tone generator

A small electronic device that issues a signal on a wire pair. When used in conjunction with a tone locator, it can help locate the termination of a wire pair. Also called a toner. - never use on wire that's connected to device's port or network adapter - can damage device or network adapter - ONLY TELLS YOU WHERE WIRE/CABLE TERMINATES

SFP (small form-factor pluggable)

A standard hot-swappable network interface used to link a connectivity device's backplane with fiber-optic or copper cabling. - provides same function as GBIC and is more compact to allow more ports per linear inch - typically used for 1Gbps connections but can support up to 5Gbps

TIA/EIA 568B

A standard pinout for RJ-45 plugs commonly used in homes and businesses.

TIA/EIA 568A

A standard pinout for RJ-45 plugs required by the federal government on all federal contracts.

GBIC (Gigabit interface converter)

A standard type of modular interface that may contain RJ-45 or fiber-optic cable ports (such as LC, SC, or ST). They are inserted into a socket on a connectivity device's backplane. Pronounced jee-bick.

straight-through cable

A twisted-pair patch cable in which the wire terminations in both connectors follow the same scheme. - most common type of network cable - also known as patch cable - allows signal to pass "straight through" from one end to an other (pin 1 to pin 1) - terminate RJ-45 plugs at both ends of cable identically, then apply either T568A or T568B - used to connect computers and other end user devices to networking devices such as hubs or switches

toner and probe kit

A two-piece tool that includes both a tone generator and a tone locator. Used together, they can help locate the termination of a wire pair. - ONLY TELLS YOU WHERE WIRE/CABLE TERMINATES

Fast Ethernet

A type of Ethernet network that is capable of 100-Mbps throughput. - uses 4 pairs of twisted pair wiring - 1 pair sends data - 1 pair receives data - the other 2 pairs not used for data transmission

Gigabit Ethernet

A type of Ethernet network that is capable of 1000-Mbps, or 1-Gbps, throughput. Requires Cat 5e or higher cabling. - uses all four pairs of twisted pair cabling for sending and receiving data transmissions

XFP (10 Gigabit small form-factor pluggable)

A type of SFP that can send and receive data at rates of up to 10 Gbps. - lower power consumption than SFP+

SFP+

A type of SFP that can send and receive data at rates of up to 16 Gbps. - theoretical max transmission speed (bandwidth)

rollover cable

A type of cable in which the terminations on one end are exactly the reverse of the terminations on the other end. - It is used for serial connections between routers and consoles or other interfaces. - DB-9 - DB-25 - reverses all the wires regardless of how they are paired - cable terminations are mirror image (completely reversed) of each other - also called console cables - used to connect computer to console port of a router

twisted-pair

A type of cable similar to telephone wiring that consists of color-coded pairs of insulated copper wires, each with a diameter of 0.4 to 0.8 mm. Every two wires are twisted around each other to form pairs, and all the pairs are encased in a plastic sheath. - most likely to be used on ethernet networks

coaxial cable

A type of cable that consists of a central metal conducting core (often copper), surrounded by an insulator, shielding, and an outer cover. Today this cable, called "coax" for short, is used to connect cable Internet and cable TV systems. - foundation for Ethernet networks in 1980s - replaced by twisted pair and fiber optic - but still used for cable internet and TV - insulator is usually PVC or teflon - metal shielding or sheath made from PVC or expensive fire resistant plastic - specifications are assigned an RG specification number; measures materials used for shielding and conducting cores which influences transmission characteristics - size of core measured in AWG (american wire guide); larger the AWG, smaller the diameter of the core

RG-59 (radio guide 59)

A type of coaxial cable characterized by a 75-ohm impedance and a 20 or 22 AWG core conductor, usually made of braided copper and used for relatively short connections. - distributing video signals from central receiver to multiple monitors within a building - less expensive, but suffers from greater attenuation - larger the AWG, the smaller the core

RG-6 (radio guide 6)

A type of coaxial cable with an impedance of 75 ohms and an 18 AWG core conductor. used for television, satellite, and broadband cable connections, typically over long distances - larger the AWG, the smaller the core

DB-25 connector

A type of connector with 25 pins that's used in serial communication and conforms to the RS-232 standard. - used on monitors, printers, and other printer devices - legacy connector

DB-9 connector

A type of connector with nine pins that's used in serial communication and conforms to the RS-232 standard. - used on monitors, printers, and other peripheral devices - legacy connector

UPC (Ultra Polished Connector)

A type of ferrule in which the tip has been highly polished, thereby increasing the efficiency of the connection. - used on SMF connectors - back reflection worsens this connection over time

MMF (multimode fiber)

A type of fiber-optic cable containing a core that is usually 50 or 62.5 microns in diameter, over which many pulses of light generated by a laser or LED (light-emitting diode) travel at different angles. - signals experience greater attenuation than SMF - not suited for distances over a few Km - less expensive; used to connect routers, switches, and servers on backbone of network or to connect workstation to network

SMF (single mode fiber)

A type of fiber-optic cable with a narrow core of 8 to 10 microns in diameter that carries light pulses along a single path from one end of the cable to the other end. - laser generated light travels a single path over the core, reflecting very little - accommodates the highest bandwidth and longest distances without repeaters of all transmission media - is the transmission media that makes up the Internet backbone - very high cost however

crimper

A tool used to attach a connector onto the end of a cable, causing the internal RJ-45 pins to pierce the insulation of the wires, thus creating contact between the conductors at each wire.

FDM (frequency division multiplexing)

A type of multiplexing that assigns a unique frequency band to each communications subchannel. Signals are modulated with different carrier frequencies, then multiplexed to simultaneously travel over a single channel, then demultiplexed at the other end - assigns frequency bands to create multiple frequency bands, each used by a subchannel, so that multiple signals can transmit on the line at the same time - once used by telephone companies

STDM (statistical time division multiplexing)

A type of multiplexing that assigns time slots to nodes (similar to TDM), but then adjusts these slots according to priority and need. - uses all time slots rather than leaving some unused, maximizing available bandwidth on network

simplex

A type of transmission in which signals may travel IN ONLY ONE DIRECTION - ex's: broadcast radio or garage door openers

duplex

A type of transmission in which signals may travel in both directions over a medium simultaneously. - achieved by: - pairing two wires together inside cable where one wire sends and one receives - transmitting two or more signals across same wire

full-duplex

A type of transmission in which signals may travel in both directions over a medium simultaneously; also called, simply, duplex. - modern NICs use this by default - ex. talking over the phone (both ppl can talk at same time)

half-duplex

A type of transmission in which signals may travel in both directs over a medium, but ONLY ONE DIRECTION AT A TIME

alien crosstalk

Electromagnetic interference induced on one cable by signals traveling over a nearby cable.

QSFP+

Generally the same technology as QSFP while supporting data rates over 40 Gbps. - highest attainable transmission at this time (2020) is 112 Gbps (4 x 28 Gbps)

APC (Angle Polished Connector)

The latest advancement in ferrule technology that uses the principles of reflection to its advantage by placing the end faces of the highly polished ferrules at an angle to each other, thus reducing the effect of back reflection. - not as sensitive to degradation from back reflection - INDUSTRY STANDARD FOR ANGLE IS 8 DEGREES

RTT (round trip time)

The length of time it takes for a packet to go from sender to receiver, then back from receiver to sender. is usually measured in milliseconds.

attenuation

The loss of a signal's strength as it travels away from its source. - type of network flaw - signals fade with distance - repeaters (regenerate digital signal in OG form) compensate for this - ethernet switch also works to compensate for this

LC (local connector)

The most common 1.25-mm ferrule connector, which is used with single-mode, fiber-optic cable. - can have UPC or APC polish - has full duplex

MTRJ (Mechanical Transfer-Registered Jack)

The most common type of connector used with multimode fiber-optic cable. - no polish - has 2 fibers in single ferrule - has full duplex

twist ratio

The number of twists per meter or foot in a twisted-pair cable. - more twists per foot = more resistant the pair will be to crosstalk or noise - high ratio can result in more attenuation though (high ratio usually requires more cabling)

pinout

The pin numbers and color-coded wire assignments used when terminating a cable or installing a jack, as determined by the TIA/EIA standard. - these stnadars developed with reducing crosstalk in mind

RJ-45 (registered jack 45)

The standard connector used with shielded twisted-pair and unshielded twisted-pair cabling.

RJ-11 (registered jack 11)

The standard connector used with unshielded twisted-pair cabling (usually Cat 3) to connect analog telephones.

console port

The type of port on a router used to communicate with the router itself, such as when making configuration changes to the device.

Ethernet port

The type of port that connects devices on a LAN; it uses an RJ-45 connector. - allow for network communications and are the type of port used to create LANs through the router

latency

the delay between the sending and receiving of a signal - type of network flaw (degrades network performance) - length of cable affects this - also existence of connectivity device such as router affects this - modems (convert/modulate incoming/outgoing network signals) produce much more latency than repeaters, which just re transmit OG signal - measured in RTT (round trip time)

hot-swappable

A component that can be installed or removed without disrupting operations.

crossover cables and Ethernet types

- 2 crossed pairs are compatible with fast Ethernet, which only uses two pairs - 4 crossed pairs are compatible with gigabit Ethernet, which uses all four pairs

3 types of multiplexing used on copper lines

- TDM (time division multiplexing) - STDM (statistical time division multiplexing) - FDM (frequency division multiplexing)

three types of multiplexing used with fiber optic cables

- WDM (wavelength division multiplexing) - DWDM (dense wavelength division multiplexing) - CWDM (coarse wavelength division multiplexing)

drawbacks of fiber optic cables

- cost: most expensive transmission medium - cabling/transmitters adn connectivity equipment almost 5 times more expensive than copper UTP/STP - optical loss

two important NIC settings

- direction in which signals travel over media - number of signals that can traverse media at any given time - relates to duplexing (full, half, multi)

benefits of fiber optic cables

- extremely high throughput (up to 100 gigabits or 100,000 megabits) - very high resistance to noise (fiber does not conduct electricity or transmit signals, so it is immune to EMI) - Excellent security - Can carry signals extremely far distances before repeaters are needed (high noise resistance + light having almost no resistance)

3 factors that degrade/distort a network performance (network flaw)

- noise - attenuation - latency

cabling on legacy networks

- straight through cables connect unlike devices - crossover cables connect like devices

1000Base-T

A Physical layer standard for achieving 1 Gbps over twisted-pair cable.

10GBase-T

A Physical layer standard for achieving 10-Gbps data transmission over twisted-pair cable.

1000Base-LX

A Physical layer standard for networks that specifies 1-Gbps transmission over fiber-optic cable using baseband transmission. The LX represents its reliance on long wavelengths of 1300 nanometers. - covers longer distances but has less total throughput - used for backbones connecting buildings in a MAN or for connecting an ISP with its telecommunications carrier - max distance MMF: 550m - max distance SMF: 5000m - supports MMF and SMF

1000Base-SX

A Physical layer standard for networks that specifies 1-Gbps transmission over fiber-optic cable using baseband transmission. The SX represents its reliance on short wavelengths of 850 nanometers. - max distance: up to 550m - supports MMF only - max distance depends on: - modal bandwidth used to transmit signals - diameter of fiber core (smaller = further distance) - ONLY 1 REPEATER ALLOWED per cable segment

100Base-T

A Physical layer standard for networks that specifies baseband transmission, twisted-pair cabling, and 100-Mbps throughput. is also known as Fast Ethernet.

core

A cable's central component that is designed to carry a signal, such as glass or plastic fibers in fiberoptic cable or strands of copper in twisted-pair cable.

open circuit

A circuit in which necessary connections are missing, such as occurs when a wire breaks.

BNC connector

A coaxial cable connector type that uses a turn-and-lock (or bayonet) style of coupling. - is crimped, compressed, or twisted on coax cable - male connector provides its own conducting pin, unlike F-connector - used more with RG-59 cables - much less common today

media converter

A device that enables networks or segments running on different media to interconnect and exchange signals. - used to convert things like Ethernet to fiber optic signals or vice versa - also used to convert MMF fiber to SMF fiber

light meter

A device that measures the amount of light power transmitted on a fiber-optic line. Also called OPM (optical power meter).

OPM (optical power meter)

A device that measures the amount of light power transmitted on a fiber-optic line. Also called light meter. - MEASURES OPTICAL LOSS

PoE splitter

A device that splits the Power over Ethernet signal and sends it to two connectors: an Ethernet jack and a power connector - allows device not rated for PoE to receive power from it

cable tester

A device that tests cables for one or more of the following conditions: continuity, segment length, distance to a fault, attenuation along a cable, near-end cross-talk, and termination resistance and impedance.

repeater

A device used to regenerate a digital signal in its original form. operate at the Physical layer of the OSI model. - compensate for attenuation in networks

CFP (centum form-factor pluggable)

A fiber-optic transceiver intended for 100-Gbps network connections. - small and energy efficient

QSFP (quad small form-factor pluggable)

A fiber-optic transceiver that 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).

BiDi transceiver

A fiber-optic transceiver that supports bidirectional transmission on both its ports. - uses WDM technology to separate data travelling in each direction on different wavelengths of light - must be deployed in pairs with this transceiver on each side of cable - more expensive than duplex transceivers but reduce fiber cabling by half while maintaining same data throughput

Cat 5 (Category 5)

A form of UTP that contains four wire pairs and supports up to 100-Mbps throughput and a 100-MHz signal rate. Required minimum standard for Fast Ethernet. -

multiplexing

A form of transmission that allows multiple signals to travel simultaneously over one medium. - increases amount of data that can be transmitted in a given timespan over given bandwidth - medium's channel is logically separated into multiple smaller channels or sub-channels - a multiplexer (mux): can combine multiple channels into one; required at transmitting end of channel - a demultiplexer (demux) separates combined channels at receiving end of channel

TDR (time domain reflectometer)

A high-end instrument for testing the qualities of a cable. - can report on: - bad connectors - crimps - bends - short circuits - cable mismatches - bad wiring - etc. - sometimes included in high tech cable performance testers

Cat 5e (Enhanced Category 5)

A higher-grade version of Cat 5 wiring that supports a signaling rate of up to 350 MHz and a maximum throughput of 1 Gbps, making it the required minimum standard for Gigabit Ethernet. - higher quality copper - higher twist ratio - advanced methods to reduce crosstalk

Cat 6a (Augmented Category 6)

A higher-grade version of Cat 6 wiring that further reduces attenuation and crosstalk, and allows for potentially exceeding traditional network segment length limits. - supports up to 10 Gbps or signal rate of 500 MHz - can reliably transmit data at multigigabit per second rates - backwards compatible with Cat 5, 5e, and 6 - can replace lowr level cabling without connector/equipment changes

Cat 7a (Augmented Category 7)

A higher-grade version of Cat 7 wiring that will possibly support up to 100-Gbps throughput and up to 1000-MHz signal rate. ISO standards for Cat 7a cabling are still being drafted and simulations conducted. - supports from 40-100 Gbps throughput

RFI (radio frequency interference)

A kind of electromagnetic interference that can be generated by broadcast signals from radio or TV antennas. - is a type of EMI (electromagnetic interference) - also a type of network noise

modal bandwidth

A measure of the highest frequency of signal a multimode fiber-optic cable can support over a specific distance. is measured in MHz-km. - higher the number, the further a MMF fiber can reliably carry a signal - related to distortion that occurs when multiple pulses of light, although issued at same time, arrive to destination at different times

multimeter

A simple instrument that can measure multiple characteristics of an electric circuit, including its resistance, voltage, and impedance. - resistance = opposition to electrical current - measured to verify cable is properly conducting electricity - impedance = tells you where faults in a cable lie - check for noise on wire (extraneous voltage) - tests for short circuits and open circuits

transceiver

A modular interface that can be inserted in a switch to connect its motherboard with an external, fiber-optic cable. - inserted in switch sockets to connect to motherboard and can be upgraded later as needed - these devices must be paired based on supported speeds and protocols

WDM (wavelength division multiplexing)

A multiplexing technique in which each signal on a fiber-optic cable is assigned a different wavelength, which equates to its own subchannel. - works with any fiber optic cable to carry multiple light signals simultaneously by dividing light beam into different wavelengths, or colors, on single fiber - similar to how prism divides white light (with each color being its own subchannel) - multiplexing type with fiber optic cables - only two wavelengths or channels per strand of fiber - 2 channels

DWDM (dense wavelength division multiplexing or dense WDM)

A multiplexing technique used over single-mode or multimode fiber-optic cable in which each signal is assigned a different wavelength for its carrier wave. - increases number of channels provided by normal WDM to 80-320 channels - can be amplified en route and is used with high-bandwidth or long distance WAN links - ex. btw ISP and NSP (network service provider) - type of multiplexing with fiber optic

CWDM (coarse wavelength division multiplexing or coarse WDM)

A multiplexing technique used over single-mode or multimode fiber-optic cable in which each signal is assigned a different wavelength for its carrier wave. - lowers cost by spacing frequency bands wider apart to allow for cheaper transceiver equipment - can support 4,8,16,or 18 channels per fiber - effective distance more limited because signal is not amplified - type of multiplexing for fiber optic cables

OTDR (optical time domain reflectometer)

A performance testing device for use with fiber-optic networks which can accurately measure the length of the fiber, locations of faults, and many other characteristics. - measures attenuation - reports on mismatched connectors

TX/RX reverse

A problem caused by mismatched pinout standards, resulting in near end crosstalk. - straight through or crossover standards for cable pin outs mismatched - The transmit and receive wires are mismatched or incorrectly aligned

speed and duplex mismatch

A problem that occurs when neighboring devices are using different speed or duplex configurations and results in failed transmissions.

patch cable

A relatively short section (usually between 3 and 25 feet) of cabling with connectors on both ends.

STP (Shielded twisted-pair cable)

Helps protect against EMI and RFI. Compare to UTP - twisted pair wires that are individually insulated as well as surrounded by shielding made of metallic substance - shielding acts as barrier to prevent external electromagnetic forces while maintaining electrical energy inside cable - cable must be grounded to enhance protective effects and prevent reflection issues - effectiveness determined by: - level and type of environmental noise - thickness and material used for the shield - grounding mechanism - symmetry and consistency of the shielding

bit rate

In digital transmissions, a measurement of throughput and bandwidth that is expressed as bits transmitted per second.

T568A wiring

Standards for wiring twisted-pair network cabling and RJ-45 connectors and have the green pair connected to pins 1 and 2 and the orange pair connected to pins 3 and 6. - pg. 250 - green pair = transmitting cables (fast ethernet) - oragne pair = receiving cables (fast ethernet)

T568B

Standards for wiring twisted-pair network cabling and RJ-45 connectors and have the orange pair using pins 1 and 2 and the green pair connected to pins 3 and 6. - pg. 250 - orange pair = transmitting cables (fast ethernet) - green pair = receiving cables (fast ethernet)

cladding

The glass or plastic shield around the core of a fiber-optic cable. reflects light back to the core in patterns that vary depending on the transmission mode. - allows fiber to bend around corners without diminishing integrity of light based signal

802.3at

The IEEE standard that improves upon the older 802.3af by supplying more power (up to 25.5 watts) over Ethernet connections (PoE)

802.3af

The IEEE standard that specifies a way of supplying electrical power (up to 15.4 watts) over twisted-pair Ethernet connections, also known as PoE (Power over Ethernet).

continuity

The ability of a cable to carry a signal to its destination.

throughput

The amount of data that a medium transmits during a given period of time. Throughput is usually measured in megabits (1,000,000 bits) per second, or Mbps. - how much data is actually transmitted

bandwidth

The amount of data that could theoretically be transmitted during a given period of time.

optical loss

The degradation of a light signal on a fiber-optic network as it travels away from its source.

ferrule

The extended tip of a fiber-optic cable connector that encircles the fiber strand to keep it properly aligned and ensure that it makes contact with the receptacle in a jack or other connector.

Ethernet cabling and network speed

a cable's category (CAT 5e or CAT 6) determines the fastest network speed it can support - device's NIC also rated for max network speeds which are defined by various Ethernet standards - Ethernet generally thought of as layer 2 protocol but has layer 1 functions

Caution when using serial cables that terminate in RJ-45 connector

be certain to plug it into appropriate serial interface - using incorrect cable type can damage sensitive equipment

What cable troubleshooting tool is capable of issuing pass/fail certifications/tests for CAT standards?

cable performance tester

noise

can degrade or distort a network signal/performance and is measured in decibels - type of network flaw - 2 common sources: - EMI/RFI - crosstalk

MMF connectors

classified by the number of fibers in fiber optic cable

The most major/notable drawback of fiber optic cabling (as of now)

cost of fiber optic cabling (very expensive)

fiber cleaver

cuts a clean slice through the inner fiber strands of a fiber optic cable during cable termination

which troubleshooting device is useful for testing a transceiver's functionality or checking for a transceiver mismatch?

loop-back adapter

crosstalk

occurs when the signals of one wire affect the signals on an adjacent wire - a type of network noise - 3 kinds: 1. alien (occurs between two cables, not wires in a cable) 2. NEXT (near end) (btw wire pairs near source of a signal) 3. FEXT (far end) (measured at far end of cable from signal source)

Major factor that inhibits the scalability and distance of fiber optic cables?

optical loss

Biggest drawback of fiber optic cables

optical loss: degradation of light signal after it travels a certain distance away from its source - occurs over long distances - can be made worse from dust or oil in between connections

which cable troubleshooting tool works on fiber optic cables and reports the optical loss of each cable?

optical power meter

auto negotiation setting

setting on NICs that allows it to select best link speed and duplex setting that is supported by neighboring device

fiber stripper

strips off the outer layers of a fiber optic cable during fiber optic cable termination

what is a telltale factor for ascertaining where faults in a cable lie?

very high or very low impedance on a cable - can signify damaged wire, incorrect pairing, or a termination point - tells you where electrical current has stopped or become inhibited

EMi affects which type of network the most?

wired networks

RFI affects which type of network the most?

wireless networks