Networking Glossary — Internet Speed Terms Explained

Plain-English definitions for every internet and networking term you'll encounter — from Mbps and latency to DOCSIS and bufferbloat.

Speed

Mbps

The standard unit for measuring internet connection speed.

Gbps

1 Gbps = 1000 Mbps — the speed tier of modern fiber plans.

Bandwidth

The maximum amount of data that can flow through a connection at once — the pipe width, not the water speed.

Download Speed

How fast your connection pulls data from the internet to your device.

Upload Speed

How fast your device sends data to the internet — the metric that matters for video calls, live streaming, and cloud backup.

Throughput

The actual data transfer rate measured under real conditions — what a speed test measures.

Bitrate

Bitrate: The number of bits transmitted or processed per second — the fundamental measure of data throughput for streaming, downloads, and network connections…

Performance

Latency

The time it takes for data to travel from your device to a server and back.

Ping

The round-trip time in milliseconds between your device and a server — the gaming metric that matters most.

RTT

Round-Trip Time — total time for a packet to travel from sender to destination and back.

Jitter

The variation in ping over time — the metric that breaks video calls and causes lag spikes.

Packet Loss

The percentage of data packets that fail to reach their destination — the most damaging network metric for real-time applications.

Bufferbloat

Excessive latency caused by your router queueing too many packets — the hidden cause of lag during downloads.

QoS (Quality of Service)

QoS is a router feature that prioritises specific types of network traffic to ensure latency-sensitive applications get bandwidth before background tasks.

SQM (Smart Queue Management)

SQM is an advanced router feature that prevents bufferbloat by actively managing queue depth, keeping latency low even when the connection is fully saturated.

Connection Types

Symmetric Speed

A connection where upload speed equals download speed — the defining advantage of fiber over cable.

Fiber Internet

Internet delivered over glass fibre cables — the fastest, most reliable residential broadband technology.

Cable Internet

Broadband delivered over coaxial cable TV infrastructure — fast download, limited upload, shared with neighbours.

5G

5G is the fifth generation of cellular wireless technology, offering peak speeds of 1–10 Gbps and low latency — used for both mobile data and as a home internet alternative via fixed wireless access.

DSL

DSL (Digital Subscriber Line): Broadband internet delivered over existing copper telephone lines. Plain-English definition covering ADSL, VDSL, and how DSL…

GPON

GPON (Gigabit Passive Optical Network): A fiber-optic access technology that shares a single fiber strand among multiple premises using passive optical…

LEO Satellite

LEO Satellite (Low Earth Orbit): Satellites at 550–1,200 km altitude used by Starlink and similar services to deliver broadband with much lower latency than…

XGS-PON

XGS-PON: A 10 Gbps symmetric passive optical network standard used by ISPs to deliver multi-gigabit fibre broadband — how it differs from GPON and why it…

Infrastructure

DNS

The internet's phonebook — translates domain names like google.com into IP addresses.

IP Address

A unique numerical label assigned to every device on a network — your internet identity.

NAT

How your router lets multiple devices share a single public IP address.

DOCSIS

The protocol that runs broadband internet over cable TV coaxial cable infrastructure.

IPv6

The successor to IPv4 — provides vastly more IP addresses and eliminates the need for NAT.

ISP

The company that provides your internet connection — Xfinity, AT&T, Spectrum, and similar.

CGNAT (Carrier-Grade NAT)

CGNAT is a technique where your ISP shares a single public IP address across multiple customers, which prevents direct port forwarding and can affect gaming and self-hosting.

VPN (Virtual Private Network)

A VPN encrypts your internet traffic and routes it through a remote server, masking your IP address and preventing your ISP from seeing your activity.

DHCP (Dynamic Host Configuration Protocol)

DHCP is the protocol that automatically assigns IP addresses to devices on a network. Your router runs a DHCP server that hands out addresses when devices connect.

ASN

ASN (Autonomous System Number): A unique identifier assigned to each network on the internet that controls its own routing policy. Plain-English definition.

CDN

CDN (Content Delivery Network): A network of servers that caches content close to users to reduce latency and load times. Plain-English definition with…

CIDR

CIDR (Classless Inter-Domain Routing): A compact notation for expressing IP address ranges and subnet sizes, such as 192.168.1.0/24. Plain-English definition…

CNAME

CNAME (Canonical Name): A DNS record type that aliases one domain name to another, allowing multiple hostnames to point to the same destination. Plain-English…

Default Gateway

Default Gateway: The router IP address that your device sends traffic to when the destination is outside your local network. Plain-English definition with…

Edge Computing

Edge Computing: Processing data close to where it is generated rather than sending it to a distant cloud data center, reducing latency for real-time…

FQDN

FQDN (Fully Qualified Domain Name): The complete, unambiguous domain name specifying a host's exact location in the DNS hierarchy. Plain-English definition…

Gateway

Gateway: A network node that connects two different networks and translates between their protocols — the bridge between your local network and the internet…

IPv4

IPv4 (Internet Protocol version 4): The original 32-bit IP addressing system that powers most internet traffic, providing about 4.3 billion addresses…

Kernel Network Stack

Kernel Network Stack: The OS kernel subsystem that processes network packets — implementing TCP/IP, routing, firewall rules, and socket APIs. How the Linux…

LAN

LAN (Local Area Network): A network connecting devices within a limited area — your home, office, or building — as opposed to the WAN that connects to the…

Loopback

Loopback: The special IP address 127.0.0.1 (or ::1 in IPv6) that routes traffic back to the local machine itself — used for testing and local network services…

MPLS

MPLS (Multiprotocol Label Switching): A high-performance routing technique that forwards packets using short labels instead of long IP addresses, enabling…

Multicast

Multicast: A one-to-many IP delivery method where a single packet is sent to a group address and routers duplicate it only where needed — used for IPTV, live…

Netmask

Netmask (Subnet Mask): A 32-bit number that divides an IP address into network and host portions, telling your device which addresses are local vs. which…

Network Tunnel

Network Tunnel: A method of encapsulating one network protocol inside another to carry traffic across incompatible networks or create encrypted private paths …

Port

Port: A 16-bit number that identifies a specific process or service within a networked device — allowing multiple services to share one IP address…

Private IP

Private IP Address: An IP address from RFC 1918 reserved ranges (10.x.x.x, 172.16–31.x.x, 192.168.x.x) used within local networks and not routed on the public…

Proxy

Proxy Server: An intermediary server that forwards requests between clients and destination servers — used for caching, filtering, anonymity, and bypassing…

Public IP

Public IP Address: A globally unique IP address assigned by your ISP that identifies your network on the internet. Every connection you make to a website…

Subnet

Subnet: A logical subdivision of an IP network, defined by a network address and subnet mask, that groups devices into isolated segments to improve security…

TLD

TLD (Top-Level Domain): The last segment of a domain name — .com, .org, .net, .uk — managed by ICANN and delegated to registry operators. Plain-English…

URL

URL (Uniform Resource Locator): The complete address of a resource on the web — scheme, host, port, path, query string, and fragment. How browsers parse URLs…

VLAN

VLAN (Virtual LAN): A logical network segment created on a managed switch that isolates broadcast domains without requiring separate physical hardware — used…

VPS

VPS (Virtual Private Server): A virtualized server environment running on shared physical hardware — giving dedicated CPU, RAM, and storage resources with root…

WAN

WAN (Wide Area Network): A network that spans a large geographic area — connecting homes and offices to the internet, or linking branch offices across cities…

WHOIS

WHOIS: A query protocol that returns registration information about domain names and IP addresses — registrant contact details, registrar, registration dates…

Hardware

Router

The device that connects your home network to the internet and routes traffic between your devices.

Modem

The device that connects your home to the ISP's network by converting their signal into Ethernet.

ONT

Optical Network Terminal — converts the fiber signal into Ethernet. The fiber equivalent of a modem.

Wi-Fi

Wireless local area networking — the radio link between your devices and router.

Ethernet

Wired network connection via cable — faster, more reliable, and lower latency than Wi-Fi.

SSID (Wi-Fi Network Name)

An SSID is the visible name of a Wi-Fi network. Devices use the SSID to identify and connect to a specific wireless network.

Wi-Fi 6 (802.11ax)

Wi-Fi 6 is the sixth generation of Wi-Fi, offering higher speeds, better performance in dense device environments, and improved battery efficiency through OFDMA and TWT.

MAC Address

MAC Address (Media Access Control): A unique hardware identifier burned into every network interface card. Plain-English definition with examples.

NAS

NAS (Network Attached Storage): A dedicated file server connected to your network that provides shared storage accessible by all devices — without needing a…

NIC

NIC (Network Interface Card): The hardware component that connects a computer to a network — handling Ethernet or Wi-Fi at the physical layer. Plain-English…

PHY

PHY (Physical Layer): The lowest layer of the OSI model responsible for transmitting raw bits over a physical medium — cable, fibre, or radio. Also refers to…

PoE

PoE (Power over Ethernet): A standard that delivers electrical power alongside data over standard Ethernet cables — eliminating the need for separate power…

QAM

QAM (Quadrature Amplitude Modulation): A modulation technique that encodes multiple bits per symbol by varying both signal amplitude and phase — used in Wi-Fi…

RJ45

RJ45: The 8-pin modular connector used for Ethernet networking — the rectangular plug at the end of every network cable. Plain-English definition including…

Server

Server: A computer or software process that provides services, data, or resources to other computers (clients) over a network — from web servers to DNS servers…

SFP

SFP (Small Form-factor Pluggable): A hot-swappable transceiver module that plugs into a switch or router to provide fibre optic or copper connectivity — used…

Switch

Network Switch: A Layer 2 device that connects multiple devices on a LAN and forwards Ethernet frames only to the correct destination port using MAC address…

Trunk Port

Trunk Port: A switch port configured to carry traffic from multiple VLANs simultaneously using 802.1Q VLAN tagging — connecting switches to each other or to…

Diagnostics

Traceroute

Maps the network path between your device and a destination, hop by hop with latency per router.

Network Architecture

Static IP

A permanently-assigned IP address — required for hosting services that must be reachable at a stable address.

Reverse Proxy

A server in front of backend applications that handles TLS, load balancing, caching, and security.

Email Authentication

MX Record

DNS record specifying which mail server is responsible for receiving email for a domain.

SPF

Sender Policy Framework — lists IPs authorized to send mail for a domain.

DKIM

DomainKeys Identified Mail — cryptographic signature on outgoing email.

DMARC

Policy that ties SPF and DKIM to the visible From: domain.

Smart Home

Matter

The unified smart home application standard from Apple, Google, Amazon, and Samsung.

Additional Network Terms

BGP

The Border Gateway Protocol that lets autonomous systems announce routes across the global internet.

Firewall

A filtering system that allows or blocks network traffic based on rules, state, applications, or identity.

Fiber

Glass or plastic strands that carry data as light, powering modern long-haul and last-mile broadband.

MQTT

A lightweight publish/subscribe messaging protocol commonly used by IoT and smart home devices.

IGMP

The protocol IPv4 hosts use to join and leave multicast groups on local networks.

SMB

The file and printer sharing protocol used by Windows, NAS appliances, and many home servers.

API

API (Application Programming Interface): A defined contract that lets one piece of software request data or services from another. Plain-English definition…

Cache

Cache: A temporary store of data kept close to where it is needed to reduce fetch time. Plain-English definition covering DNS cache, browser cache, and CDN…

Half-Duplex

Half-Duplex: A communication mode where data flows in both directions but only one direction at a time — like a walkie-talkie. Plain-English definition versus…

IoT

IoT (Internet of Things): The network of physical devices — thermostats, cameras, appliances — that connect to the internet to send and receive data…

Network Topology

Network Topology: The physical or logical arrangement of devices and connections in a network — star, bus, ring, mesh, and hybrid. How topology affects…

Packet

Packet: A small unit of data sent across a network, containing a header with routing information and a payload with the actual content. All internet traffic…

Wireless

WiFi 6E

Extension of WiFi 6 into the 6 GHz band — more spectrum, less congestion.

WiFi 7

Seventh-generation WiFi with 320 MHz channels, Multi-Link Operation, and 4K QAM.

Captive Portal

Sign-in page presented before guest WiFi access — common at hotels, airports, cafes.

Backhaul

Backhaul: The high-capacity link that connects a local network or access point back to the core internet infrastructure. Plain-English definition with examples.

BSSID

BSSID (Basic Service Set Identifier): The MAC address of a Wi-Fi access point's radio, uniquely identifying each wireless network in the area. Plain-English…

Mesh Network

Mesh Network: A Wi-Fi system where multiple nodes communicate with each other to extend coverage, eliminating dead zones without separate SSIDs or manual…

MIMO

MIMO (Multiple-Input Multiple-Output): A Wi-Fi antenna technology that uses multiple antennas to transmit and receive data simultaneously, increasing…

OFDMA

OFDMA (Orthogonal Frequency Division Multiple Access): A Wi-Fi 6 technology that divides a channel into sub-channels called resource units, letting a router…

Protocols

NTP

Network Time Protocol — synchronizes clocks across the internet to within milliseconds.

VoIP

Voice over IP — phone calls transmitted as digital packets over IP networks.

ARP

ARP (Address Resolution Protocol): The protocol that maps IP addresses to MAC addresses on a local network. Plain-English definition with examples.

DSCP

DSCP (Differentiated Services Code Point): A 6-bit field in IP packet headers used to classify and prioritize traffic for Quality of Service. Plain-English…

FTP

FTP (File Transfer Protocol): A standard network protocol for transferring files between a client and server over TCP. Plain-English definition covering FTP…

HSTS

HSTS (HTTP Strict Transport Security): A web security policy that forces browsers to only connect to a site over HTTPS, preventing downgrade attacks…

HTTP

HTTP (Hypertext Transfer Protocol): The foundation protocol of the web that defines how browsers request and receive web pages from servers. Plain-English…

HTTPS

HTTPS (HTTP Secure): HTTP with TLS encryption added — securing web traffic so only the browser and server can read it. Plain-English definition with how it…

ICMP

ICMP (Internet Control Message Protocol): The diagnostic protocol used by ping and traceroute to report network errors and test connectivity. Plain-English…

IMAP

IMAP (Internet Message Access Protocol): The protocol that lets email clients access and sync messages stored on a mail server. Plain-English definition versus…

MTU

MTU (Maximum Transmission Unit): The largest packet size a network interface can transmit in a single frame. Understanding MTU prevents fragmentation, black…

POP3

POP3 (Post Office Protocol 3): An email retrieval protocol that downloads messages from a mail server to your device and typically deletes them from the…

QUIC

QUIC: A modern transport protocol built on UDP that provides encrypted, multiplexed connections with faster handshakes than TCP+TLS — the foundation of HTTP/3…

SMTP

SMTP (Simple Mail Transfer Protocol): The standard protocol for sending and relaying email between mail servers and from email clients to outgoing mail…

SNI

SNI (Server Name Indication): A TLS extension that tells a server which hostname the client is connecting to, enabling one IP address to host multiple HTTPS…

SOCKS

SOCKS (SOCKS5): A proxy protocol that routes any TCP or UDP traffic through an intermediary server — more versatile than HTTP proxies as it works with any…

SSH

SSH (Secure Shell): An encrypted network protocol for remote login, command execution, file transfer, and port forwarding — the standard way to securely…

TCP

TCP (Transmission Control Protocol): The connection-oriented protocol that guarantees ordered, reliable delivery of data over the internet. Plain-English…

TTL

TTL (Time to Live): A counter in IP packets that decrements at each router hop, preventing packets from looping forever — and a DNS cache duration that…

UDP

UDP (User Datagram Protocol): A connectionless transport protocol that sends packets without guaranteeing delivery or order — used for gaming, video calls, and…

UPnP

UPnP (Universal Plug and Play): A network protocol that lets devices automatically discover each other and open router port mappings without manual…