Even in the case of the SLA, it's not the provider's problem if your network has problems.
In the case of DSL, I do believe that the speed should be measured when the modem is jacked straight into the DEMARC. Now, if that speed is too slow, then you should complain.
But if your router is overloaded, or you have ten users on a 10Mbps hub (note I did not say switch), I don't see how that's the provider's problem.
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