Interleaving is a form of error correction used when transmitting data over a network, in particular, via broadband. It helps to ensure that the information sent from one part of a network reaches another part of the network intact - i.e. when you send an email, it makes sure the person receiving your email sees it the way you intended. 

The way in which interleaving works can create latency issues (the time delay between data being sent and data being received). Computer A for instance might transmit some information to computer B. Before computer B will verify that it has the information intact it will send a portion of that information back to computer A to say "Yes, I’ve got it now, is this what you sent me?".

While having interleaving turned off may increase download speeds, it will also increase the chances of information being corrupt once it gets to its destination. Most files will not work unless the information received is correct e.g. a user might spend an entire day and 600Mb of their traffic allowance downloading a file. Even if a very small percentage of that files data is corrupt, it will render the entire file inoperable. Interleaving minimises this risk.

Can I switch off interleaving?

We want to make sure our broadband service is as reliable as possible for our customers, so our default setting is to leave interleaving on for maximum stability. If you'd rather trade some stability for increased speed and lower latency, you can contact our help desk on 0800 438 448 and request interleaving be turned off.

Please note that for VDSL broadband connections, interleaving cannot be turned off.