- BT 21CN Lines
- TT lines - via Adjusting the profile
Interleaving affects the way error detections & correction is applied to the line. These changes take a day to take effect.
With interleaving off the round trip ("ping") time is faster (around 12ms when off, around 28ms when on). However the line is less able to cope with noise, which may cause more frequent retraining and/or a lower sync speed and BRAS rate.
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
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.
The interleaving is set when selecting the line profile, see: Adjusting the profile
Controlling interleaving on a BT FTTC line is done by Openreach. It is quite hard for us to persuade BT to disable or enable interleaving. We can try though, so do ask.