This
story appeared on Network World Fusion at
http://www.nwfusion.com/columnists/2001/1008bradner.html
'Net
Insider:
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.
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