From the WSJWeb Link
"Deep-packet inspection involves inserting equipment into a flow of online data, from emails and Internet phone calls to images and messages on social-networking sites such as Facebook and Twitter.
Every digitized packet of online data is deconstructed, examined for keywords and reconstructed within milliseconds.
In Iran's case, this is done for the entire country at a single choke point, according to networking engineers familiar with the country's system......
Users in the country report the Internet having slowed to a crawl, estimated at less than a tenth of normal speeds.
Deep-packet inspection delays the transmission of online data, unless it is offset by a huge increase in processing power, according to Internet experts.
Iran is "now drilling into what the population is trying to say," said Bradley Anstis,
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