Some broadband providers deliberately slow down your download or upload speeds to ensure other customers have a stable connection - this is called web traffic management, throttling or traffic shaping.
It's less common than it used to be, but it's worth knowing what a firm's policy is before you sign up with it.
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What is broadband traffic management?
When you use the internet at peak times, you are adding to the strain on the broadband network as so many other people are doing the same. That can be made worse if some heavy users are downloading huge files, and as a result everyone's connection speed can be slowed right down.
In order to avoid this, some providers impose speed restrictions on particularly heavy users at peak times, typically in the evening. Not all firms do this, and if a provider does, its policy may depend on which package you have as well as your usage. But it's worth knowing if your speeds are likely to be restricted before you sign up for a broadband package.
Broadband providers are required to explain their approach to traffic management in your contract, and they must also publish this information. They have to tell you about any data caps and speed restrictions, and how their web traffic management policies could affect your internet service.
What's BT's traffic management policy?
BT says its broadband packages don't have any speed restrictions, even at peak times.
What's Plusnet's traffic management policy?
There is no traffic prioritisation on Plusnet's Unlimited, Unlimited Fibre or Unlimited Fibre Extra packages. However, on its business broadband packages and some of its older residential broadband packages Plusnet applies a "traffic prioritisation" policy.
This means some customers will see slower speeds when not doing 'time-sensitive' things such as using Skype or online gaming, eg, file sharing or downloading music.
What's Sky's traffic management policy?
Sky says its standard and fibre broadband packages aren't subject to traffic management. But if you have Sky Broadband Connect - a limited service for those outside its network area - speeds may be slower at peak times.
What's TalkTalk's traffic management policy?
TalkTalk says it doesn't have any speed restrictions on its broadband packages, even at peak times.
What's Virgin Media's traffic management policy?
Virgin Media says it does apply traffic management to a "small minority" of customers - but insists in practice this affects only about 1%. Those not on its VIVID 200 Gamer or VIVID 300 packages who are heavy uploaders between 6pm and 11pm are most likely to be affected, and may see a temporary speed restriction between those hours.
What about other providers?
To see what other providers do, check their website - all should publish their web traffic management policies.
It's worth noting if you have a satellite broadband package you are likely to be subject to traffic management to ensure a stable connection for all customers.
How can I tell if I'm being affected by traffic management?
The easiest way to check is to do a broadband speed test - see our Broadband Speed Test guide for the full info and how to. If you find your connection is significantly slower than usual and it's at a peak time, you may be subject to web traffic management, though you'll need to check with your provider to be sure.