TalkTalk Wholesale Line Profiles: Difference between revisions

=Profile Factors=

==SNR==

SNR is a measure of signal strength and as such is measured in Decibels (dB). The values in use on the TTT network are:

*6dB

*9dB

*12dB

*15dB

(We have requested 3dB, but it's not available yet)

==Interleaving, Error Correction and Delay==

Packets of data that are transferred across a DSL line are split down into smaller blocks of data; these are then sent sequentially sent across the DSL line. As they arrive at the receiving end, they reconstructed back into the original larger packets of data.

If one block of a larger packet is lost due to line interference, the packet can be recreated using the remaining blocks that were received; data blocks reserve some space for data which can salvage a partially damaged block. This is known as Error Correction. Interleaving can be used as a form more robust form of error correction.

The ‘Delay’ of the Interleaving is simply a measurement of the size of the interleaving buffers. The size is measured in

Milliseconds (ms).

The buffer sizes available on the TalkTalk network are:

*Off (Fast)

*8ms

*16ms

==Impulse Noise Protection==

Impulse Noise Protection (INP) is an error correction feature of ADSL2+ which makes interleaving more affective. It does

not increase delay but does add in more error correcting bits which results in a drop in line rate for less noisy lines. Because

of the increased noise immunity however, a slow noisy line will be able to sync at a higher rate with this feature enabled.

Note:

On some hardware, INP can result in a substantial drop in downstream speed and should only be used where a line is

particularly noisy and only slow speeds are achievable.