Interleaving is a method of arranging data in a non-contiguous way in order to increase performance.
Interleaving is usually associated with data communication, multimedia file formats, radio transmission or ADSL broadband. To simplify, interleaving is protection against burst-errors in a transmission. Although burst errors can cause some mayhem, these sorts of errors are actually quite rare and do not usually happen on a day to day or month to month basis.
With Local Loop unbundling now being rolled out in New Zealand, many ISPs are choosing to offer their customers the choice of whether to turn interleaving off, with some ISPs even deciding to have it turned off by default. At this current date Xtra has not decided to allow it to be turned off on it’s customers connections.
Having interleaving turned on causes higher latency (also known as ping), a great disadvantage for internet gamers. Having interleaving turned off can decrease the ping when online gaming (and other activities) quite a bit, but usually only by about 20 - 80ms, depending on whether the server is local or international. Although when online gaming, this can usually be the difference between lagging and not lagging.
I do believe that having interleaving turned off can be better for VoIP connections, but as I am not a user of VoIP, I would not be completely sure about this, and how different it may be between having interleaving turned off and when it’s turned on. As VoIP revolves around good latency, it should help to great better connections.
The interleaving on/off change is usually free. However, some ISPs will charge you for every change after your initial choice at sign-up. If you would like to make sure that you can have interleaving turned off, check through your ISP‘s FAQs to try and find out if they have it turned on/off by default. Usually all that is required is an email to be sent or a phone call to your ISP to request the change.