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Telecom & QoS glossary

Plain-English definitions of the key terms used across active testing, monitoring and service assurance.

A – D

2G / 3G / 4G / 5G — Successive generations of mobile network technology — GSM (2G), UMTS (3G), LTE (4G) and New Radio (5G) — each adding capacity, speed and lower latency.

APN (Access Point Name) — The named gateway a device uses to reach a mobile data network or packet-data service.

Availability — The proportion of time a network or service is operational and reachable, usually expressed as a percentage.

Bearer — The underlying connection that carries a service (voice, data, messaging). Bearer testing verifies the transport layer independently of the application.

Benchmarking — Measuring two or more networks side by side under identical, controlled conditions to compare real performance.

CDR (Call Detail Record) — A record generated by network elements describing a usage event (call, SMS, data session), used as the basis for rating and billing.

Coverage — The geographic area in which a network provides usable service at a defined quality level.

DHCP (Dynamic Host Configuration Protocol) — A protocol that automatically assigns IP addresses and network settings to devices.

DNS (Domain Name System) — The system that resolves human-readable hostnames into IP addresses.

Drive testing — Measuring mobile network quality from a moving vehicle, with every measurement geo-tagged via GPS for mapping and optimisation.

DSL (Digital Subscriber Line) — Broadband technology that delivers data over existing copper telephone lines.

E – L

E2E (End-to-End) testing — Testing a service across the whole chain — from the end-user device to the destination and back — to reproduce the real customer experience.

eSIM — An embedded, reprogrammable SIM that can store one or more operator profiles without a removable physical card.

FTP (File Transfer Protocol) — A standard protocol for transferring files between systems, often used as a throughput test bearer.

GRQ (Global Roaming Quality) — A GSMA framework and set of metrics for measuring and assuring the quality of roaming services.

GSM / GPRS / EDGE — 2G mobile standards: GSM for circuit-switched voice, GPRS and EDGE for packet data.

Handover — Transferring an active call or data session from one cell, frequency or technology to another without interruption.

HSPA / HSPA+ — High-Speed Packet Access — enhanced 3G technology delivering higher data rates.

IMS (IP Multimedia Subsystem) — The core network framework that delivers IP-based voice and multimedia services such as VoLTE and VoNR.

IREG — The GSMA International Roaming Expert Group. IREG testing validates voice and data interoperability between roaming partners.

Jitter — The variation in the arrival time of packets. High jitter degrades real-time services such as voice and video.

KPI (Key Performance Indicator) — A measurable value that reflects network or service performance, e.g. call setup success rate or average throughput.

Latency — The time data takes to travel from source to destination, measured in milliseconds; critical for voice, gaming and real-time apps.

LTE / LTE-Advanced — The 4G mobile broadband standard and its enhanced versions offering higher speeds via carrier aggregation.

M – R

Mediation — Collecting, normalising and correlating raw usage records from network elements before they are rated and billed.

MOS (Mean Opinion Score) — A 1–5 score representing perceived voice or video quality — historically subjective, now estimated objectively by algorithms such as POLQA.

Packet loss — The percentage of data packets that never reach their destination; even small amounts noticeably degrade real-time services.

PDP context — The set of parameters that establishes a data session, allowing a mobile device to exchange IP traffic with the packet core.

PESQ (Perceptual Evaluation of Speech Quality) — ITU-T P.862 algorithm that objectively scores narrowband and wideband voice quality.

PEVQ (Perceptual Evaluation of Video Quality) — An algorithm that objectively scores the perceived quality of video streams.

POLQA (Perceptual Objective Listening Quality Analysis) — ITU-T P.863, the successor to PESQ, designed for modern voice including HD and VoLTE.

Portal testing — Verifying the availability and performance of WAP/HTTP portals and value-added service pages.

Probe — A hardware or software unit that actively generates test traffic and measures network, service and application quality from the subscriber's perspective.

PSTN (Public Switched Telephone Network) — The traditional circuit-switched fixed-line telephone network.

QoE (Quality of Experience) — The overall quality of a service as actually perceived by the end user.

QoS (Quality of Service) — The measurable performance of a network or service, covering throughput, latency, packet loss, availability and more.

Revenue Assurance — Processes that ensure every delivered service is correctly recorded, rated and billed, preventing revenue leakage.

Roaming — Using mobile services on a visited network outside the home operator's coverage area.

RSRP (Reference Signal Received Power) — An LTE/5G measurement of received reference-signal strength, used to assess coverage.

RSRQ (Reference Signal Received Quality) — An LTE/5G measurement combining signal strength and interference to indicate signal quality.

RTP (Real-time Transport Protocol) — The protocol used to deliver audio and video streams over IP networks.

S – Z

SINR (Signal-to-Interference-plus-Noise Ratio) — A ratio indicating signal quality relative to interference and background noise; higher is better.

SIM-box fraud (interconnect bypass) — Diverting international calls over the internet and re-originating them on local SIMs to avoid legitimate termination charges.

SLA (Service Level Agreement) — A contract defining the quality and availability levels a provider commits to deliver, and the remedies if they are missed.

SMS (Short Message Service) — The standard text-messaging service carried over mobile signalling networks.

TADIG (Transferred Account Data Interchange Group) — The GSMA group that defines roaming billing record (TAP) standards. TADIG testing validates roaming settlement accuracy.

Throughput — The actual data transfer rate achieved over a connection, typically measured in Mbit/s.

UMTS — The 3G mobile telecommunications standard.

VoLTE (Voice over LTE) — Voice service carried over the 4G LTE data network via IMS, offering faster setup and HD voice.

VoNR (Voice over New Radio) — Voice service carried natively over the 5G network.

Walk testing — Measuring network quality on foot — typically indoors or in pedestrian areas — using a portable probe such as XPack.

WLAN / Wi-Fi — Wireless local-area networking used for fixed and offload connectivity, commonly included in convergent testing.