Officials said the overall uptime for the order-routing system is 99.96% for the year thus far.

CNN: Software glitch forces brief shutdown of Nasdaq

Problems with the order-routing system have caused delays on two other occasions this year.

CNN: Software glitch forces brief shutdown of Nasdaq

Exchanges have spent the last year designing order-routing algorithms and buying faster networking gear and more bandwidth to control the chaos brought on by the changes.

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Cisco's newest gear is designed to effortlessly cross back and forth over those seams, innately sensing whether a digital packet is video, e-mail or an order and routing it only to the destination that can best use it.

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As the stock market began to recover later that year, however, Datek's software for active traders began to garner a new following with its streaming data, the same bleeps and bongs as on institutional trading screens and best-execution order-routing software.

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Current headers can vary in length, which means more work for the routing hardware that has to read them in order to figure out where to dispatch each packet.

ECONOMIST: Internet protocol