Deep packet inspection
From Free net encyclopedia
Deep packet inspection is a form of computer network packet filtering that examines the data part of a through-passing packet, searching for illegal statements to decide if the packet can pass. This is in contrast to shallow packet inspection (usually called just packet inspection) which just checks the header portion of a packet.
Deep Packet Inspection (DPI) devices look at Layer 2 through Layer 7 of the OSI model. This includes headers and data paths. The DPI will identify and classify the traffic based on a signature database and will allow the user to perform many things.
A classified packet can be redirected, marked/tagged (see QoS), blocked, rate limited, and of course, reported to a reporting agent in the network.
Many DPI devices also perform the ability to identify flows rather than a packet by packet analysis.
Deep packet inspection allows phone and cable companies to "readily know the packets of information you are receiving online--from e-mail, to websites, to sharing of music, video and software downloads."Template:Ref