Comments below. See www.cybertelecom.org/security/emergency.htm --- Alexis Turner <subbies@redheadedstepchild.org> wrote:
On Wed, 21 Feb 2007, Frank Thomas wrote:
::Two basic questions: ::1/ How will an emergency community response grid work when it is based ::on Internet websites and the electricity supply breaks down ?
I've heard of a pretty amazing, advanced technology called a generator. I've heard of another one called a hand crank.
Generators need fuel. ISPs had not been considered essential services - so fuel into disaster areas either was not permitted into the zone if it was going to ISPs - or the fuel was rerouted to hospitals. This is changing, but... if you look at the assessments of 9/11 in particular, the most significant impact on the Internet was not the 9/11 event itself, but the running out of backup fuel a few days later.
::2/ At which level of traffic do Internet servers crash because of ::overload? In the old telecom times telephone routers in residential ::areas in Europe were saturated when 8% of all customers in the area
Dont compare Internet to PSTN. They are very different models. PSTN assumes that only a small percentage of subs are off hook. If more than that go off hook, the capacity of the switches are full and calls are blocked. With the Internet, in major disasters such as 9/11 and Katrina - there was no issue of switch capacity being overwhelmed and "calls" being blocked. In a scenario where the capacity of a line begins to go over 50% (I think that is the mark), error correction will kick in to slow down packet transmission. This assumes that applications are latency tolerate - which most are. Where the hosts back off on packet transmission, the data still gets through but maybe a few seconds slower. Conversely, as in the great baltimore train tunnel fire and the Chinese earthquake where links are broken, traffic is rerouted to alternative routes. Now these were extreme cases and it does take time for the traffic to get rerouted, but in general in time the traffic does get rerouted, even in the most extreme cases, as these were. During 9/11, the wireless telephone service switches were overwhelmed and calls were blocked. There are stories of individuals implementing their companies Y2K contingency plans going down the stairwell of the towers using blackberry Internet type devices - the latency tolerant distributed Internet still worked. Final point. The FCC Network Reliability and Interoperability Council has always known what an "outage" meant in terms of the PSTN. NRIC has tried to conceive of what an outage means for the Internet and has largely not succeeded - alternative terms are arising. Instead of "outage" new terms like "reachability" are being used. Okay, that had to deal with the network. For servers, at the application layer of the network, what does it take for a server to get overwhelmed? How well designed is the server?? The server host can use dynamic routing to route traffic from server A to mirror copies of the server anywhere in the world. During Rita, many server farms simply moved copies of the servers out of harms way with no impact on performance. The server host can also slash dot the server. During 9/11, traffic to servers such as CNN began to overwhelm the servers and the pipes. Therefore they stripped the websites of all frills - pictures, ads, unnecessary stuff - and just hosted text information which takes up very little bandwidth. Through the techniques of traffic management and web design, servers should do well. Final comment - then there is the issue of real time applications such as VoIP. The Net was not made for real time applications. Real time applications assume excess capacity. Where that excess capacity is challenged, real time applications may struggle. Okay, one more. Recall that during Katrina, 1000s of people moved from NO to Texas, got online, and were able to access email and their servers and what they needed. If there is a disruption in a localized portion of the net, a solution is to move to a different part of the net. Much different from the PSTN where they could not take their PSTN phone numbers with them.
in New Orleans. A ::close look on the living conditions of those who did not survive might ::protect against a too strong belief in technology.
Are you suggesting that anyone believes that email is going to stop a hurricane? I dont really understand. Katrina was an extreme catastrophe. Nevertheless, if we look at the lessons learned, we see the importance of communications in four phases (1) Alert of a coming emergency (2) During the emergency, calling for help (3) first responders and (4) restoration. The comment "too strong belief in technology" seems to be one from someone who wants to set up technology as a strawman savior, and then dismiss it. The real quest is, how can we improve the EAS. How can we improve interoperability for first responders. How can we improve restoring communication for survivors. As simple as, emergency SMS messages to phones have become a very powerful tool not just in alerting people, but tailoring the alert to specific areas with specific information (where the old broadcast model provides the same message to everyone in the broadcast area). CAP emergency messages are now being used for tsunamis, earthquakes, fires, eas, local events whatever. Technology is not going to stop the hurricane. But improved technology is helping us respond to the event. =~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~= Cybertelecom :: Federal Internet Law & Policy www.cybertelecom.org Washington hOCKEY Wiki wockey.stikipad.com News Tryouts Clubs Leagues Pickup Rinks Info