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This is the support site for Andrews & Arnold Ltd, a UK Internet provider. Information on these pages is generally for our customers but may be useful to others, enjoy!

Interleaving: Difference between revisions

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==Availability==
*BT 21CN Lines
*TT lines - via [[TalkTalk_Wholesale_Line_ProfilesTalkTalk Wholesale Line Profiles|Adjusting the profile]]
 
==Interleaving Options==
 
==More about interleaving==
[[File:Interleaving.png|none|frame|This line dropped atshortly 2amafter 11am, and reconnected with higher latency,. This could be interleaving being applied]]
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.
 
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.
 
== Good or bad? ==
[[File:Interleaving.png|none|frame|This line dropped at 2am, and reconnected with higher latency, could be interleaving being applied]]
Interleaving on lines where it can reduce errors can be a good thing for applications such as VoIP.
 
Gamers will want to reduce the latency as much as possible.
 
On a good quality line there should be no need for interleaving, but a longer line may benefit from it.
 
Errors on lines is usually a problem that needs to be fixed. Masking a fault by enabling interleaving may help, but it may be better to get to the root cause of the errors.
 
== TalkTalk lines ==
The interleaving is set whenby selecting the line profile, see: [[TalkTalk_Wholesale_Line_ProfilesTalkTalk Wholesale Line Profiles|Adjusting the profile]]
 
==FTTC==
Interleaving on a VDSL/FTTC line is managed by Openreach. It is very hard for us to persuade BT or TalkTalk to disable or enable interleaving as this requires an engineer visit and a DLM reset. This is not a service they offer. VDSL comes with interleaving automatically managed by Openreach and there is no option for us to request changes. Both BT and TalkTalk are highly reluctant for us to specifically report a fault to disable interleaving. Please do discuss this with Support, but manually disabling interleaving is not really possible.
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.
 
[[Category:Line Profiles]]
[[Category:Line_SettingsLine Settings]]
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