Advanced Networking Definition-of-Terms Reviewer

Wireless LAN (WLAN)

A local-area network that connects devices using radio waves instead of Ethernet cables.

IEEE 802.11

The family of standards that defines Wi-Fi operation, including channel use, security, and transmission behavior.

Wi-Fi 6 (802.11ax)

A Wi-Fi generation designed for higher efficiency in dense networks using OFDMA, MU-MIMO, BSS coloring, and target wake time.

Wi-Fi 6E

Wi-Fi 6 operation extended into the 6 GHz band, giving more channels and less congestion where supported.

Wi-Fi 7 (802.11be)

A newer Wi-Fi generation that improves throughput and latency using wider channels, 4096-QAM, and multi-link operation.

Access Point (AP)

A device that provides wireless clients access to a wired network.

SSID

The service set identifier or Wi-Fi network name broadcast or configured for client association.

BSSID

The MAC-address identifier of a specific access point radio or basic service set.

ESSID

A shared network name used across multiple access points to support roaming in one extended wireless network.

OFDMA

Orthogonal Frequency Division Multiple Access; divides a channel into resource units so multiple clients can transmit more efficiently.

MU-MIMO

Multi-user multiple-input multiple-output; lets an AP communicate with multiple clients at the same time using multiple spatial streams.

BSS Coloring

A Wi-Fi 6 feature that marks transmissions from different basic service sets to reduce unnecessary waiting in dense deployments.

Target Wake Time (TWT)

A power-saving feature that schedules when clients wake and transmit, useful for battery-powered devices.

Channel Width

The amount of spectrum used by a Wi-Fi channel, such as 20, 40, 80, 160, or 320 MHz.

Channel Overlap

Interference that occurs when nearby Wi-Fi networks use partially overlapping channels.

Co-channel Interference

Contention that occurs when multiple APs or clients share the same channel in the same area.

Adjacent-channel Interference

Interference caused by radios using nearby channels whose signals overlap or bleed into each other.

RSSI

Received Signal Strength Indicator; a measurement of how strong a received wireless signal is.

SNR

Signal-to-noise ratio; compares useful signal strength to background noise and affects throughput and reliability.

Roaming

The process of a wireless client moving from one AP to another while staying connected to the same WLAN.

802.11k

A roaming-support standard that helps clients discover nearby access points.

802.11v

A roaming-support standard that helps guide clients toward better access points.

802.11r

Fast BSS transition; reduces authentication delay when roaming between APs.

WPA2

A Wi-Fi security protocol commonly using AES-based encryption and PSK or enterprise authentication.

WPA3

A newer Wi-Fi security protocol that improves password protection and supports stronger encryption options.

WPA3-SAE

Simultaneous Authentication of Equals; a password-authentication method that resists offline dictionary attacks better than WPA2-PSK.

Enterprise Wi-Fi

A centrally managed WLAN that often uses controllers, RADIUS, certificates, segmentation, and monitoring.

Captive Portal

A web-based login or terms-acceptance page used before allowing network access.

RADIUS

A protocol used for centralized authentication, authorization, and accounting in enterprise networks.

EAP

Extensible Authentication Protocol; a framework used for enterprise Wi-Fi authentication methods.

Site Survey

A wireless assessment that measures coverage, interference, channel usage, and signal quality.

Heat Map

A visual representation of Wi-Fi signal strength or coverage across a floor plan.

Airtime Utilization

The percentage of time a Wi-Fi channel is busy; high airtime use can reduce performance.

Hidden Node Problem

A wireless condition where clients cannot hear each other and may transmit at the same time, causing collisions.

Band Steering

A technique that encourages clients to use a preferred band, usually 5 GHz or 6 GHz instead of crowded 2.4 GHz.

Passive Optical Network (PON)

A fiber access network that uses passive splitters to share one feeder fiber among many subscribers.

GPON

Gigabit Passive Optical Network; a PON technology commonly used for fiber-to-the-home broadband.

OLT

Optical Line Terminal; the provider-side device that controls and aggregates traffic in a PON.

ONT

Optical Network Terminal; the customer-side device that converts optical fiber signals to user-facing services.

ONU

Optical Network Unit; a customer-side optical device similar to an ONT, often used in different deployment contexts.

ODN

Optical Distribution Network; the fiber cables, splitters, connectors, and passive components between OLT and ONT/ONU.

Optical Splitter

A passive device that divides optical power from one fiber into multiple distribution fibers.

Split Ratio

The number of customers sharing one PON port, such as 1:32 or 1:64.

Downstream Transmission

Traffic sent from the OLT toward ONTs, typically broadcast downstream with each ONT accepting its own traffic.

Upstream Transmission

Traffic sent from ONTs toward the OLT using coordinated time slots to prevent collisions.

TDMA

Time Division Multiple Access; a method where ONTs transmit upstream during assigned time intervals.

DBA

Dynamic Bandwidth Allocation; the OLT process for assigning upstream bandwidth based on demand and service priority.

T-CONT

Transmission container; a GPON upstream traffic container associated with bandwidth and service behavior.

GEM Port

GPON Encapsulation Method port; a logical channel used to carry user service traffic over GPON.

OMCI

ONT Management and Control Interface; the protocol used by the OLT to configure and manage ONTS.

Optical Power Budget

The allowable optical loss between transmitter and receiver while maintaining reliable communication.

Insertion Loss

Signal loss introduced by a component such as a splitter, connector, or splice.

Attenuation

Reduction of optical signal strength as it travels through fiber and passive components.

Connector Loss

Optical loss caused by fiber connectors, dirt, poor alignment, or damage.

Reflectance

Light reflected back toward the transmitter, often caused by poor connectors or fiber events.

OTDR

Optical Time-Domain Reflectometer; a tool used to locate fiber faults, splices, breaks, and loss events.

XG-PON

A 10-gigabit-class PON standard with higher downstream capacity than GPON.

XGS-PON

A symmetric 10 Gbps PON standard supporting high upstream and downstream capacity.

NG-PON2

Next-generation PON using multiple wavelengths to increase capacity and support coexistence.

WDM-PON

Wavelength Division Multiplexing PON; assigns or uses different wavelengths for greater separation or capacity.

Coexistence Element

A component that allows different PON generations to operate on the same optical distribution network.

Reach

The maximum supported fiber distance between OLT and ONT while staying within optical and timing limits.

Ranging

The OLT process of measuring ONT distance/timing so upstream bursts arrive correctly.

Encryption in GPON

Protection used to prevent unauthorized reading of downstream traffic shared across the PON.

Rogue ONT

An unauthorized or malfunctioning ONT that can disrupt service or compromise security.

Fiber Cut

A physical break in the fiber path that causes loss of optical connectivity.

Dirty Connector

A contaminated fiber connector that can cause high loss, reflections, and unstable service.

Low Optical Receive Power

A condition where received light level is below acceptable range, causing errors or link loss.

SD-PON

Software-defined PON; applies programmability and centralized control concepts to optical access networks.

Protection Switching

A redundancy method that moves traffic to a backup path after a fiber or equipment failure.

Network Security

The set of policies, technologies, and practices used to protect network confidentiality, integrity, and availability.

Troubleshooting

A structured process for identifying symptoms, isolating causes, applying fixes, and verifying recovery.

CIA Triad

Confidentiality, integrity, and availability; three core goals of information and network security.

Authentication

The process of verifying the identity of a user, device, or service.

Authorization

The process of deciding what an authenticated identity is allowed to access or perform.

Accounting

The recording of user or system activity for audit, billing, or forensic purposes.

Least Privilege

A security principle that grants only the minimum access required to perform a task.

Role-Based Access Control

Access control based on assigned roles instead of individual ad hoc permissions.

Firewall

A control that permits or blocks traffic according to defined security rules.

Access Control List (ACL)

A rule set that filters traffic by source, destination, protocol, port, or other conditions.

IDS

Intrusion Detection System; monitors traffic or hosts for suspicious activity and alerts administrators.

IPS

Intrusion Prevention System; detects and actively blocks suspicious or malicious traffic.

Segmentation

Dividing a network into smaller zones to reduce risk and limit lateral movement.

Microsegmentation

Fine-grained segmentation often applied to workloads, services, or virtual functions.

VLAN

Virtual LAN; a Layer 2 segmentation method that separates broadcast domains.

VPN

Virtual Private Network; encrypts traffic over an untrusted network to provide secure remote or site-to-site access.

TLS

Transport Layer Security; protects data in transit through encryption and certificate validation.

DDoS Attack

A distributed denial-of-service attack that overwhelms resources using traffic from many sources.

Rate Limiting

A control that restricts request or traffic volume to reduce abuse or overload.

Patch Management

The process of applying updates to fix vulnerabilities, bugs, and stability problems.

Log Analysis

Reviewing logs to identify errors, attacks, policy changes, and root-cause evidence.

Baseline

A known-normal measurement of performance or behavior used for comparison during troubleshooting.

Latency

Delay experienced by traffic from source to destination.

Jitter

Variation in packet delay, especially important for voice, video, and real-time applications.

Packet Loss

The percentage or count of packets that fail to reach the destination.

Throughput

The actual data rate successfully delivered over a network path.

MTU

Maximum Transmission Unit; the largest packet size a link can carry without fragmentation.

DNS Failure

A condition where name resolution fails, causing users to lose access even when IP connectivity may work.

Routing Leak

An unintended advertisement or visibility of routes between networks or tenants.

Incident Report

A record of affected systems, timeline, symptoms, evidence, root cause, actions taken, and prevention steps.