Internet connection glossary

Technical terms explained in one or two sentences.

Speed and measurement

Download speed: how fast you receive data, in Mbps.
Upload speed: how fast you send data.
Mbps: megabits per second, the unit of speed. 8 Mbps = 1 MB/s. See Mbps vs MB/s.
Gbps: gigabits per second, i.e. 1,000 Mbps.
Ping / latency: round-trip time of a packet, in milliseconds (ms).
Jitter: variation in ping from one packet to the next.
Packet loss: share of data lost on the way, causing glitches in games and calls.
Bandwidth: a link's maximum capacity, often confused with real speed.

FTTH: Fibre To The Home. See how fibre works.
GPON / XGS-PON: passive optical network technologies used for home fibre.
OLT: the provider's equipment at the exchange that sends the optical signal.
Splitter: a passive component that shares one fibre among several subscribers.
Distribution point (PCO): the floor or street box where your fibre is connected.
Optical wall socket (PTO): the fibre socket installed in your home.
ONT: the box that converts light into an electrical signal, sometimes built into the router.
LOS: Loss Of Signal, a red light meaning no optical signal. See red LOS light.
Attenuation (dBm): loss of optical signal power.

ADSL: internet over the copper phone line; speed depends on distance.
VDSL2: a faster evolution of ADSL on short lines.
Sync rate: the speed negotiated between the modem and the provider's equipment.
3G: third generation mobile network, now the slowest still in use.
4G / LTE: fourth generation mobile network.
5G: fifth generation: more speed and lower latency.
4G/5G router: a home router that uses the mobile network.

Router: the device that distributes internet in your home.
2.4 GHz / 5 GHz Wi-Fi: frequency bands; 2.4 GHz reaches further, 5 GHz is faster. See which band to choose.
Wi-Fi 6 / Wi-Fi 7: recent Wi-Fi generations. See Wi-Fi 6 and Wi-Fi 7.
Mesh: several access points covering the home under one network name.
Powerline: carrying the network over electrical wiring.
Cat 5e / Cat 6 Ethernet cable: network cables rated for at least 1 Gbps.
ASN: the number that identifies a provider's network on the internet.