Unlike traditional telephony networks, modern networks have to carry a lot of different types of data. Nowadays they transport a bewildering variety of data, from voice to video, Skype to Facebook. The technology of networks has changed too. In the past networks were 'circuit switched', meaning that a continuous connection was established to carry data. Today's networks are packet switched where instead of travelling via a single communications channel; data is 'packet-ised' into tiny segments of information that is transmitted in a haphazard way. Not so long ago, a network only had to deal with voice data, some necessary signalling traffic and the occasional fax. Things have changed a lot since then and a modern telephony network is required to deal with many different types of data and traffic. The voice, signalling and fax traffic is still there but in addition to this a network carries email, the World Wide Web, instant messaging, Voice over IP traffic and a multitude of data from different applications.
The reach of the Internet has today expanded well inside enterprise networks. Modern enterprise networks are also increasingly carrying large volumes of confidential data and are accessed by thousands of employees. The increased connectivity has therefore raised some serious security threats as well. This calls for security software and devices that can identify security threats and unauthorized network activity or data transfer in time.
In addition to enterprise IT security departments, law enforcement agencies and intelligence agencies also require the capability to look into the data passing through a network in real-time. Deep packet inspection is a useful technology for this function. Certain deep packet inspection devices can be integrated with a network and can identify specific communication content at full packet rates from multiplexed data streams in real-time. Besides the monitoring of high-speed networks such devices can also prevent network intrusion attempts and filter unauthorized and harmful content such as spam and viruses.
It's almost impossible for a network operator to know exactly what is travelling across their network at any time and this presents serious issues of management and efficiency. This is where deep packet inspection comes to the rescue. Deep packet inspection enables a network operator to look inside individual packets of data to examine the contents. It helps them to understand the makeup of their network traffic and to plan their network resources accordingly.