It is 7 years to the day when the 9/11 tragedies happened in the USA. The event has different memories for us all. I was attending a SIP Summit VoIP conference in Austin Texas and Tuesday 11th September was the first day. The conference was abandoned after the first day and most Americans hired cars and drove home. In some cases it was a 3 day drive.
The experience of overseas attendees was a strange and highly stressful one as noone knew when they would be able to go home. I eventually made it out on the Saturday on a very nervous flight. The barman at the airport hotel where we were staying said that we were the first regulars he had ever had.
The event was quite significant from a technology perspective. The mobile networks in New York stayed working although it was virtually impossible to get a line. The fixed line network did not work – the Central Office (telephone exchange) in the area had burnt to the ground.
What did remain up was the internet and students at Columbia University, which is where Professor Henning Schulzerinne did much of the development of VoIP signalling protocol SIP, were able to call home using their University VoIP accounts.
Internet Protocol, the IP in VoIP, was designed to run over networks resilient to nuclear attack. 9/11 was a good, if terrible, real life test bed for this.