Laws of Internet Resource Supply and Demand

Payload consumes bandwidth and application turns consume latency

Like most systems, the Internet is subject to the laws of resource supply and demand. Demand for Internet resources that affect speed is most heavily influenced and driven by the way websites are designed and operated. The primary factors influencing the demand for resources that affect page load time are payload size and application turn count. Payload consumes bandwidth resources, and application turns consume latency.

(This posting is part of a series about NetForecast's newly published report FCC's "Measuring Broadband America" Report Tells Only Half the Story).

Supply and Demand for "Speed-limiting" Internet Resources

It is important to look at these factors because payload size and turn counts are growing at incredible rates. The following figure shows that payload growth is exponential. NetForecast has measured average payload size for typical business-oriented websites since 1995, and during that time payload size has experienced a compound annual growth rate (CAGR) of 20% from 50K Bytes in 1995 to 960K Bytes per page today. NetForecast started measuring when a Fortune 50 company asked us to study the effect of the web on their corporate network. Later, we used the Keynote Business 40 as the proxy for typical business websites. Many consumer websites generate much more traffic per page.

A recent phenomenon contributing to payload traffic growth is a dramatic increase in what we call "clandestine traffic" or behind-the-scenes traffic of which users are largely unaware. This includes cookies, content prefetching, updates, etc. For example, website 'background' traffic accounts for about 15K Bytes per second and Google Chrome "features" add another 6K Bytes per second. This hidden traffic is not shown in the following figure, but if added to the natural growth of web page size it nearly doubles the CAGR to 37%.

The hidden traffic of Google Chrome is alarming. For example, just launching a Chrome browser generates 36K Bytes of traffic in the first 60 seconds.

Google may argue that the improved Chrome user experience justifies the various hidden traffic sources that accumulate over a day. Perhaps--but the consumer is not told of the cost, and bandwidth is not free.

Payload Growth from 1995 to 2011

Application turn count (number of network round trips) has also dramatically risen (see the figure below) from 20 in 1995, to 124 today, a compound annual growth rate increase of 12%. Given that the speed of light is a fundamental barrier, the more turns in a web page or application, the greater the latency and the slower the user experience.

Application Turn Count Growth from 1995 to 2011

Click here to get the FCC report.

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Copyright © 2011 IDG Communications, Inc.

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