bandwidth management

Many Internet users worry about net neutrality and online privacy these days. And they see deep packet inspection (DPI) as their arch enemy. Common claims are that DPI reads the content of all packets and then decides based on the nature of the content whether to forward, slow down or drop that packet. This is a misconception based on poor understanding how today’s DPI for Internet traffic management works.

DPI is only the core technology of traffic management systems that is used for application classification. This is done by scanning the first few packets — including their payload — of each network flow for certain patterns out of a predefined list. DPI does not ‘read’ or even ‘understand’ any communication content. As soon as the communicating application of a network flow is identified, DPI stops for that flow. Then, bandwidth management rules determine how this flow is treated. Possible rules are: