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Interleaving: Difference between revisions
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The options are "Set interleave off", "Set interleave on" and "Set auto interleave" (interleave is automatically controlled by the exchange depending on the measured stability of the line).
==More about interleaving==
On broadband lines there is a key factor that affects the latency. Lines use a technique called Forward Error Correction which allows small errors in the signal to be corrected without having to resend the data. This only works for small errors (e.g. one bit), but sometimes lines have interference (called Impulse Noise) which affects lots of bits at a time (a click or pop on the line, in effect). To fix this a technique called interleaving is used. It spreads each packet out over a longer time, interleaving it with other packets. When there is impulse noise the effect is a small error in a whole series of packets, each of which can be corrected.
The downside is that, whilst the overall speed is the same, interleaving adds latency. Typically around 8ms is added to all communications on the line, though there are different levels of interleaving (or Impulse Noise Protection) which cause even higher latency. The latency added is however consistent, which can, in itself, be an important factor for on-line games.
This is a slight challenge: with interleaving the line has extra latency all the time, but without it you get errors. When there is an error then the packet has to be resent, which adds a lot more latency but randomly and inconsistently. Usually interleaving is a better choice, but it does depend in the interference. In some cases interference is only at certain times of day, and if that is not when you are playing, then interleaving is best turned off.
There is often one other option, which is running the line at a lower speed. This can remove the interference if it is only at certain frequencies, and as we explained above, the speed is not necessarily a key factor.
== TalkTalk lines ==
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