Module 4: Physical Layer - Cisco Introduction to Networks (ITN v7.0)

Vocabulary practice flashcards covering Module 4: Physical Layer of Cisco CCNA Introduction to Networks (ITN v7.0), including physical standards, signaling, copper/fiber cabling, and wireless media.

Network Interface Card (NIC)

A hardware component that physically connects an end device or host to a network via a wired or wireless connection.

Physical Layer

The layer in the network architecture that accepts a complete frame from the data link layer, encodes it into a series of signals, and transports the bits across physical network media.

Physical Layer Standards Organizations

The governance bodies that establish hardware specifications for the physical layer, including ISO, EIA/TIA, ITU-T, ANSI, and IEEE.

Physical Components

The hardware devices, media, and connectors—such as NICs, cable designs, interfaces, and connector materials—that transmit signals representing bits.

Encoding

The process of converting a stream of data bits into a predefined, predictable pattern and format recognizable by the receiving device in the network path.

Manchester Encoding

An encoding technique where bit values are represented by voltage transitions occurring at the middle of each bit time interval.

Signaling

The method of representing binary bit values ($1$ and $0$) on the transmission medium using electrical pulses, light pulses, or microwave frequencies.

Bandwidth

The capacity at which a transmission medium can carry data, measuring the quantity of bits that can travel from one point to another in a given unit of time.

Latency

The total duration of time, including transmission and processing delays, required for data to travel from one point to another across a network.

Throughput

The actual measure of bits transferred across a network medium over a specified duration of time.

Goodput

The measure of usable application data transferred over a given period of time, calculated as $\text{Goodput} = \text{Throughput} - \text{traffic overhead}$.

Attenuation

The degradation and loss of signal strength that occurs as an electrical or optical signal travels longer distances across a physical medium.

Electromagnetic Interference (EMI) and Radio Frequency Interference (RFI)

External interference signals caused by electromagnetic or radio frequency sources that can distort, disrupt, and corrupt copper data transmissions.

Crosstalk

The disturbance caused when the electric or magnetic fields of an electrical signal in one wire interfere with the signal traveling in an adjacent wire.

Cancellation

A noise-reduction mechanism where two wires in a circuit pair carry opposing electrical polarities so their surrounding magnetic fields cancel each other and reject outside EMI/RFI.

Unshielded Twisted-Pair (UTP) Cable

The most widely used networking cable, consisting of four color-coded pairs of copper wires twisted together within a flexible plastic jacket without internal metal shielding.

Shielded Twisted-Pair (STP) Cable

A copper cable providing superior noise protection over UTP by enclosing wire pairs in individual foil shields as well as an overall braided or foil outer shield.

Coaxial Cable

A copper cable consisting of an inner copper conductor, flexible plastic insulation, a woven copper braid or foil outer conductor/shield, and a protective outer jacket.

Coaxial Connectors (BNC, N type, F type)

Connectors used to terminate coaxial cabling in installations such as wireless antenna connections and cable broadband internet.

TIA/EIA-568

The commercial telecommunications cabling standard that governs cable types, lengths, connectors, termination pinouts, and testing methods for copper wiring.

RJ-45 Connector

The standardized 8-pin modular connector used to terminate twisted-pair Ethernet cables.

Ethernet Straight-Through Cable

A UTP cable terminated with the identical wiring standard (either T568A on both ends or T568B on both ends), used to connect an end host to a network intermediary device.

Ethernet Crossover Cable

A legacy UTP cable wired with standard T568A on one end and standard T568B on the other, designed to link like devices directly (such as host to host, switch to switch, or router to router).

Rollover Cable

A proprietary Cisco cable pinout used to connect a workstation serial port to the console port of a switch or router via an adapter.

Fiber-Optic Cabling

A transmission medium constructed of extremely thin, flexible strands of pure glass that uses pulses of light from lasers or LEDs to transmit data over long distances with immunity to EMI/RFI.

Single-Mode Fiber (SMF)

Optical fiber featuring a small core ($9\,\mu\text{m}$) and using laser light sources to provide a single straight path, ideal for long-distance and carrier applications.

Multimode Fiber (MMF)

Optical fiber featuring a larger core ($50\,\mu\text{m}$ or $62.5\,\mu\text{m}$) that uses LED emitters transmitting light at multiple angles, carrying up to $10\,\text{Gbps}$ up to $550\,\text{meters}$.

Dispersion

The spreading out of a light pulse over time as it traverses an optical fiber, leading to loss of signal clarity and restricting the maximum cable distance.

Straight-Tip (ST) Connector

An early bayonet-style, twist-lock fiber-optic connector.

Subscriber Connector (SC)

A widely used fiber-optic connector featuring a square, push-pull latching mechanism for quick insertion and removal.

Lucent Connector (LC) Simplex Connector

A small-form-factor fiber connector that uses an RJ-style retaining tab, designed for high-density patch panels.

Duplex Multimode LC Connector

A paired small-form-factor fiber connector containing two LC terminations in one housing to accommodate simultaneous send and receive paths.

Fiber Patch Cord Color Coding

The color standard used for fiber cable outer jackets, where yellow signifies single-mode fiber cables and orange (or aqua) signifies multimode fiber cables.

Wi-Fi (IEEE 802.11)

The industry standard technology used to provide wireless local area networking (WLAN) over radio frequencies.

Bluetooth (IEEE 802.15)

A low-power wireless personal area network (WPAN) standard engineered for short-range communication between paired computing and peripheral devices.

WiMAX (IEEE 802.16)

A wireless communications standard that employs a point-to-multipoint topology to deliver broadband wireless network connectivity over broader geographical areas.

Zigbee (IEEE 802.15.4)

A low data-rate, low power-consumption wireless networking specification designed primarily for smart devices and Internet of Things (IoT) applications.

Wireless Access Point (AP)

A network hardware device that concentrates wireless RF signals from client devices and bridges them onto the wired Ethernet infrastructure.