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Emergency service in a best-effort world

By Scott Bradner
Network World, 10/08/01

For many years the phone system could give special handling to selected phone calls.

This feature is designed to be used in times of emergency by medical services, some government officials, firefighters, police and some industry emergency response teams. A year or two ago some people started trying to figure out how to provide emergency services over the Internet.

The experiences in the aftermath of the events of Sept. 11 made thinking about this both more and less important.

The current system in the U.S. is known as the Government Emergency Telecommunications Service. This PIN-based system provides expedited handling of call requests, but does not include preemption of calls already in progress. It is provided by telephone companies under a government fee-for-service contract.

Clearly, with the movement toward converged networks, it makes sense to look at the impact of emergencies on vital Internet-based services. But just understanding what vital services might encompass on the Internet is not easy. In the phone world there is basically one service: a fixed-bandwidth voice call. With the Internet, there are hundreds of applications that might be important when responding to emergencies. Dealing with each application individually would be a daunting task, made all the harder by the people that keep creating new applications.

One proposal that is being discussed by the Internet Engineering Task Force, the Telecommunication Standardization Sector of the International Telecommunications Union and European Telecommunications Standards Institute is based on the International Emergency Preparedness Scheme. As you can see by looking at the mailing list archives reachable through the Web page, this proposal has created some spirited discussions.

Much of the discussion concerns the fundamental differences between the circuit-based, guaranteed quality, access controlled phone network and the packet-based, best-effort Internet as well as what did and did not happen on Sept. 11. The Internet infrastructure did not collapse that day, but many Web servers and some tail circuits were way overloaded. This means that special traffic handling of emergency-related traffic in ISP backbones may be much less important than ensuring priority access to network-based servers or tail circuits.

Much more work needs to be accomplished to understand just what should be done in this area, and just as important, what is not worth the effort to do.

Disclaimer: Now who would claim that Harvard is not worth the effort? Maybe M.I.T. Anyway, the above observation is my own.