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It’s a curve not a point!

By Scott Bradner

The Internet is not good enough, or so many people would have us believe. It does not have good enough quality for IP telephony or for IP-based VPNs. It does not have good enough security for remote access or for IP-based VPNs. It does not have enough reliability for IP-based FAXs or EDI. All in all, if you listen to these pundits the Internet does not seem to be of much use for anything real.

There is a common theme to these pronouncements of uselessness. They assume that there is some point of acceptability of a service. Since that has repeatedly been shown to not be the case in the real world it is reasonable to wonder the real world understanding of these pundits.

This is not a new misunderstanding. A number of years ago one of the telephone company standards groups did an exhaustive survey to determine the minimum quality that was needed in the telephone system. This involved a lot of experiments and survey work and is frequently sited as a landmark study of its type. (Though I've not been able to track down a copy.) My problem with the work was what conclusions were drawn from the effort. A point of acceptable quality was determined. This misunderstands the dynamics of the marketplace.

For many years most traditional telephone companies refused to invest in the infrastructure to support cellular phones because the voice quality did not meet the acceptable minimum and the assumption was that no one would want to use the service. It was only after the frequency spectrum was opened up and new providers were able to show that customers wanted the service that the main-line phone companies moved.

The people who say that the Internet is not good enough for one application or another are missing the same detail that the phone companies did -- there is not a single point of acceptability, it is a curve of quality vs. other factors. Other factors could include convenience, as was the case with cell phones, cost, service coverage, ease of use, and there are many more.

CNN ran a story on IP telephony a week ago that interviewed someone who is using an IP telephony service. This is a service where you dial the number of a local gateway from your regular phone, the call is then routed over the Internet to a gateway near the call destination where it is put back on the local phone network. He said that there were a few problems with the quality but seemed quite happy with the cost-quality tradeoff.

Note that the functions available in the Internet for security, reliability and quality are changing all the time so such tradeoffs are not static and should be reviewed over time.

You should look closely at any pronouncement that a particular service can not be successfully run over the Internet and see if there is a missing curve in the assumptions - remember the cell phone.

disclaimer: Since Harvard does not make pronouncements and this is one it must be my own.