Last reviewed: 22 March 2026
This glossary covers the most common broadband terms you will encounter when comparing deals, reading provider contracts, or switching service. Each definition is written in plain English with links to relevant guides where they can help you understand the topic further.
Fibre to the premises: a broadband connection where fibre-optic cable runs all the way to your home with no copper section. FTTP delivers the fastest and most consistent speeds available, typically ranging from 100 Mbps to over 1 Gbps. See our full fibre vs standard broadband comparison.
Fibre to the cabinet: fibre runs from the exchange to a green street cabinet, then copper telephone wiring carries the signal the remaining distance to your property. Speeds typically range from 30 to 80 Mbps and degrade with distance from the cabinet. See our connection types guide.
Asymmetric Digital Subscriber Line: broadband delivered entirely over copper phone lines from the exchange to your home. ADSL typically delivers 10 to 17 Mbps download and around 1 Mbps upload. It is the slowest fixed-line broadband type still in use and is being gradually phased out as fibre rollout continues.
Broadband delivered over a hybrid fibre-coaxial (HFC) network, primarily operated by Virgin Media in the UK. Cable uses fibre to a local node and coaxial cable for the final connection. It can deliver speeds up to 1 Gbps but availability is limited to cabled areas. See our connection types guide.
A home internet service delivered over a 4G mobile network using a plug-in router with a SIM card. Useful where fixed-line options are limited or unavailable. Speeds depend heavily on signal strength and network congestion and are typically 20–50 Mbps, though they can vary significantly by location.
Home internet using the 5G mobile network, offering higher potential speeds than 4G (often 100–300 Mbps in good conditions). Availability depends on 5G coverage at your address, and indoor signal can be affected by building materials. Check provider coverage maps before ordering.
The rate at which data travels from the internet to your device, measured in megabits per second (Mbps). Download speed determines how quickly web pages load, videos stream, and files download. Most provider headline speeds refer to download speed. See our speed needs guide.
The rate at which data travels from your device to the internet, measured in Mbps. Upload speed affects video calls, cloud backups, sending large email attachments, and live streaming. Upload is often much slower than download on FTTC and ADSL, but full-fibre plans typically offer significantly better upload.
The delay between sending a request and receiving a response, measured in milliseconds (ms). Lower latency means a more responsive connection, which is particularly important for video calls, online gaming, and real-time applications. FTTP and cable tend to have lower latency than ADSL. See our speed guide.
Variation in latency over time. While latency is the average delay, jitter measures how much that delay fluctuates from one moment to the next. High jitter can cause choppy video calls, audio glitches, and inconsistent online gaming performance even when average speed and latency are acceptable.
The number of users sharing the same bandwidth at the local network level. A contention ratio of 50:1 means up to 50 households share the same capacity back to the exchange or node. Lower ratios mean less peak-time congestion. Providers rarely publish this figure, but it partly explains why speeds drop during busy evenings.
The company that maintains the UK's largest telephone and broadband network infrastructure, including exchanges, cabinets, and the fibre/copper lines to most premises. Openreach is a subsidiary of BT but operates as a separate, regulated business. Most UK broadband providers (except Virgin Media and some alternative networks) use the Openreach network to deliver service.
The broadband Universal Service Obligation: a legal right for every UK household and business to request a decent broadband connection of at least 10 Mbps download and 1 Mbps upload. If your current connection falls below this and no commercial option is available, you can request an upgrade from BT or KCOM (in Hull). The installation is funded up to a reasonable cost threshold.
The UK-wide switching process for most fixed-line broadband, introduced by Ofcom. You contact your new provider, and they coordinate the switch, including notifying your old provider and setting the switchover date. You do not need to contact your old provider separately in most cases. See our switching hub.
A 14-day window after signing up (for distance sales, such as online or phone orders) during which you can cancel without paying an exit fee. If the service has already been activated, you may be charged for any usage during that period. Always check the specific provider's terms, as some charge a setup-fee portion.
A one-off charge added to your first bill or paid upfront when you start a new broadband contract. It covers activation, equipment dispatch, or engineer installation. Setup fees vary from £0 (often waived in promotions) to £60 or more if an engineer visit is required for new-build FTTP connections.
An early termination charge applied if you leave a broadband contract before the minimum term ends. The amount typically reduces month by month over the contract period. Some providers calculate exit fees as the remaining monthly payments; others use a fixed schedule. Always check the exit fee before signing up.
A lower-cost broadband package offered by some providers to customers receiving certain means-tested benefits such as Universal Credit, Pension Credit, or Employment and Support Allowance. Social tariffs are typically £10–£20 per month for speeds of 30–80 Mbps with no fixed contract. Not all providers offer them. Next step: read our social tariffs guide.
The download speed available to at least 50% of a provider's customers at peak time (8–10 pm), as defined by Ofcom's voluntary code of practice. Providers must display this figure prominently. Your actual speed may be higher or lower depending on your line, equipment, and local network conditions. See our speed guide.
A speed floor written into your contract by some providers. If your connection consistently falls below this level and the provider cannot fix the issue within 30 days, you may have the right to exit without penalty. Not all providers offer a minimum guaranteed speed, so check your contract terms.