Tag: "virus"

Posted June 25, 2012 by christopher

Far too many people seem to think that when they go to Speedtest.net to test their connection, they get a number that has any bearing on reality. For most of us, it simply doesn't. This is true of other large tools for measuring connections. And it has important policy implications because the FCC contracted with a company called Sam Knows to measure wireline speeds available to Americans (I'm a volunteer in that project).

Sam Knows explains :

SamKnows has been awarded a ground breaking contract by the Federal Communications Commission (FCC) to begin a new project researching and collecting data on American fixed-line broadband speeds delivered by Internet Service Providers (ISP's) - until now, something that has never been undertaken in the USA.

The project will see SamKnows recruit a team of Broadband Community members who will, by adding a small 'White Box'’ to their home internet set up, automatically monitor their own connection speeds throughout the period of the project.

Unfortunately, SamKnows appears to be documenting fantasy, not reality.

To explain, let's start with a question Steve Gibson recently answered on his amazing netcast, Security Now (available via the TWiT network). A listener asked why he gets such large variation in repeated visits to Speedtest.net.

Security Now Logo

Steve answers the question as an engineer with a technical explanation involving the TCP/IP protocol and dropped packets. But he missed the much larger issue. Packets are dropped because the "pipes" are massively oversubscribed at various places within the network (from the wires outside you house to those closer to the central office or head end). What this means is that the cable company (and DSL company, to a lesser extent) takes 100Mbps of capacity and sells hundreds of people 20Mbps or 30 Mbps or whatever. Hence the "up to" hedge in their advertisements.

The actual capacity you have available to you depends on what your neighbors (cable) or others in the network (DSL) are doing. Dropped packets in TCP result often result from the congestion of high oversubscription ratios.

This gets us into why Speedtest.net and Sam...

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