ninjee writes "The New York Stock Exchange is re-examining its network after it was forced to close four minutes early at 3:56pm on Wednesday (1 June) because of a communications glitch. Trading opened on time (09:30 EDT) the following morning but the outage irked traders and raised questions about the reliability of a network described as 'ultra reliable' following improvements made in the wake the September 11 terrorist attacks. The outage stemmed from a fault in a system designed to distribute market data and operate computer trading systems. NYSE Chief Executive John Thain said that both the main system and its backup were swamped with error messages, Reuters reports. He added that the exchange would carry out remedial work designed to prevent any repetition of the problem."