Broadband is sold in acronyms. Most of them describe something simple, and knowing which is which occasionally saves real money — the difference between “fibre broadband” and “full fibre” is a genuine difference in what arrives at your house, and only one of those phrases is precise.
Grouped by where you will meet them.
How the connection reaches you
FTTP — Fibre To The Premises. Fibre optic cable all the way into your building. The fastest and most reliable consumer option. Also called full fibre or FTTH (Fibre To The Home). This is the one you want.
FTTC — Fibre To The Cabinet. Fibre to the green street cabinet, then existing copper phone line for the last stretch. Sold for years as “fibre broadband”, which caused endless confusion. Speed depends heavily on how far you are from the cabinet — this is why two neighbours get different results on the same package.
ADSL. Copper all the way, the oldest technology still sold. Typically under 20 Mbps. Being phased out.
Cable / DOCSIS. Virgin Media’s network, using coaxial cable. Fast downloads, historically weaker uploads, though this is improving.
FWA — Fixed Wireless Access. Delivered by radio from a local mast to an antenna on your building. Common in rural areas. Not the same as mobile broadband.
Satellite. From orbit. Reaches almost anywhere; higher latency.
SOGEA — Single Order Generic Ethernet Access. FTTC without a phone line. As landlines move onto broadband, this is increasingly what “broadband only” means on an Openreach line.
The physical kit
Master socket. The main phone socket where the line enters your house, usually by the front door. Everything else is an extension, and extensions cost speed.
ONT — Optical Network Terminal. A small white box installed with full fibre, where the fibre terminates. Your router plugs into it. Sometimes called a modem.
Router. Shares one connection between your devices and provides Wi-Fi.
Mesh. Multiple units working as one Wi-Fi network, handing devices between them. The standard fix for coverage problems in larger houses.
Speed and performance
Mbps / Gbps. Megabits and gigabits per second. Note bits, not bytes — a 100 Mbps connection downloads at roughly 12 megabytes per second, because there are 8 bits in a byte. This is why downloads look slower than the advertised number.
Download / upload. Coming to you, and going from you. Upload is the under-discussed one: it determines whether you freeze on video calls.
Symmetric. Upload equals download. Common on full fibre, valuable if you work from home.
Average speed. The advertised figure. Means at least half of customers achieve it at peak time. Not a promise to you.
Minimum guaranteed speed. A personalised figure given at sale for your line. This is the one with rights attached — persistently below it and unfixed, and you can usually leave penalty-free.
Latency / ping. Round-trip time in milliseconds. Matters enormously for gaming and calls, barely at all for streaming.
Jitter. Variation in latency. Worse than high latency for voice and video.
Contention. Sharing capacity with neighbours. Why evenings are slower.
Throttling / traffic management. A provider deliberately slowing certain traffic. Rare on modern fixed-line packages; more common on mobile.
Contracts and billing
Minimum term. The period you have committed to. Leaving early normally means paying the remaining months.
ETC — Early Termination Charge. What leaving early costs.
Out of contract. Past the minimum term. Free to leave any time — and usually paying more than a new customer for the same thing. This is where most households lose money.
Mid-contract rise. A price increase during your term. New consumer contracts must state it in pounds and pence upfront rather than tying it to inflation.
Setup / activation fee. A one-off charge. Trivial over 24 months, potentially larger than a month’s rental on a rolling deal.
Social tariff. A cheaper package for households on qualifying benefits. Usually exempt from annual price rises.
One Touch Switch. The current switching process: you contact only the provider you are moving to, and they handle the rest.
Networks and who owns what
Openreach. Owns the largest UK access network. Does not sell to you directly — BT, Sky, TalkTalk, Zen and many others sell over it.
Altnet. Any network operator that is not Openreach or Virgin Media. Over a hundred of them, mostly regional, frequently cheaper.
Wholesale. A network that sells to retail ISPs rather than to consumers. You cannot buy direct.
Wayleave. Legal permission from a building’s owner to install equipment. The usual reason fibre is on your street but not in your block of flats.
MDU — Multi-Dwelling Unit. Industry term for a block of flats.
CP — Communications Provider. The industry’s word for an ISP.
Technical terms you may hit when something breaks
IP address. Your connection’s address on the internet.
Static vs dynamic IP. Static does not change. You need it if you host something reachable from outside; most people do not.
CGNAT — Carrier Grade NAT. Your provider shares one public IP address between many customers. Saves scarce addresses, and mostly invisible — until you try to reach your home security camera or games console from outside and cannot. If remote access suddenly stopped working after switching provider, CGNAT is the likely cause. Most providers will move you off it or sell a static IP if you ask.
PPPoE. A login method some providers use. If you replace your router, you may need your PPPoE username and password from the provider.
DNS. Translates domain names into addresses. Changing it can help performance slightly; malware sometimes changes it maliciously.
Port forwarding. Letting outside traffic reach a specific device inside your network. Needed for some cameras, servers and games. Does not work behind CGNAT.
Packet loss. Data that never arrives. Destroys real-time applications.
The five that actually change decisions
If you skim, learn these:
- FTTP vs FTTC — full fibre versus part-copper. A real difference in what you get.
- Upload speed — the number that determines whether video calls work properly.
- Minimum guaranteed speed — your only enforceable speed figure.
- Out of contract — the state in which most people overpay.
- CGNAT — why remote access to your own devices stopped working.
Sources
- ofcom.org.uk — Ofcom — consumer guidance and terminology
- ofcom.org.uk — Ofcom — contract terms, guaranteed speeds and price rises
- openreach.com — Openreach — network technologies
- ofcom.org.uk — Ofcom — Connected Nations, technology definitions