[Gllug] BE Broadband (was Off Topic: Backup ISP)

[Jason Clifford]

On Sun, 2011-03-27 at 20:01 +0100, Mick Farmer wrote:
> One thing puzzles me though.  Our current ISP, Plusnet, say
> that 6 MBps is the best our line will support.  BE say that
> we should expect 11 MBps.
> 
> Why is there such a discrepancy when the circuit is going to
> run over the same local loop?  All explanations gratefully
> received as always.

The reason is in the way each of them arrives at their estimate for your
line performance.

Plusnet essentially just take the result of the BT wholesale DSL
availability checker for your line and give you some response based upon
that. Almost all ISPs provide their estimate based upon this.

Be have a different approach. They run a check on the line which
responds with the line length as well as the same data that other ISPs
use and calculate the expected line performance based upon line length
and an assumption of the line SNR and attenuation. This usually allows
them to offer a better (and more accurate) estimate but it generally
only works out that way for Be because they wont process an order to
deliver service on a line that is likely not to perform well (or at
least that used to be the case - I don't know whether it still is).

Of the two approaches the one followed by Be is better for "normal"
lines but if your line is subject to interference or other such factors
using the BT Wholesale data is likely to give a more realistic
expectation of how the line may operate. Generally the BT Wholesale data
is very conservative these days.

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