DPI (Deep Packet Inspection)

The rapid growth and popularity of broadband service presents both opportunities and challenge for carriers. On the other hand, the popularization of such service as, P2P,online games,WebTV and VoIP means that many people are now using and enjoying these service and telling their friends abotu them, so the number of usrs is growing larger everyday. On the other hand,carriers now have to resolve a series of problems in relation to bandwidth management,content billing and information security

The most obvious problem has to do with P2P application.P2P technology in effect clears a path through the C/S traffic model.By adopting a non concentrated server mode, it is able to penetrate and break up server bottleneck and so it is now being widely used in many domains including downloading,streaming and VoIP.According to the statistic data, at present, P2P traffic accounts for over 50% of all online traffic and the percentage is growing higher all the time.Many people are even saying that P2P is a killer application or revolutionary technology.However most carriers' network planning and construction mode are not suitable for the P2P applications traffic model

In addition most network equipment is lacking int terms of efficient technical monitoring, so P2P application would not recognized if used. As a result,carriers are unable to properly identify or manage network applications.Hence their networks are always congested and operations are in a state of confusion pr facing some technical dilemma

Another barrier reratding carriers' development is that they are unable to implement content billing.Content billing means that a carrier is able to perform in depth analysis in data packets,differentiate type of user service and set reasonable rates according to service features
At present, as data services and content services have been developing, the lack of complete content billing modes make it virtually impossible to convert service increase into equivalent benefits.

What makes things worse is that the benefits derived from some services have even decreased. In providing voice, IM (instant messageing) and game applications, ISP and ICPs utilize cheap network resource to attract and develop users and recieve a huge portion of the profits. leaving carriers helpless, receiving an insubstantial portion of the profits.

Thus far content billing become an important threshold feature upon which are wireless carriers have started to deploy content billing and fixed netwrok carreirs are also investigating useful steps in this direction

Content security presents another headache for carriers.Over the past few years, intrussions and attacks from online hackers have resulted in huge loss for carriers.Although a firewall can repel some of these attacks, it offers little if any protection againts viruses that are hiden in IP packet net loads.Currently, network attacks have been gradually shifted toward high level application.According to recent statistics released by Gartner, the application layer has been the target of over 70% of network attacks, and the percentage is still increasing steadily.Therefore,content security has become a key focus in information security

While carriers are failing to identify services, implement content billing and not meeting information security demands, they are on the one hand being forced to pay more in terms of operation costs and are recieving lower customer satisfaction in return. Therefore, a major concern for carriers is acquiring the ability to perceive network applications and provide network service control and management measures, so that their networks are both operable and manageable

A positive step in this direction is the recent development of DPI.Deep Packet Inspection is a new technology is comparasion to ordinary message analysis.Ordinary message inspection only analyze contents under layer 4 of each IP packet, which includes the source address, destination address, source port, destination port and protocol type.So on this basis DPI is capable of implementing analysis on the application layer that can identify applications and their contents

In fact, DPI technology has already been applied in the security protection system of intranets.Since its application scope is relatively samll, it has thus far not attracted much attention,However the forces that are currently driving it to center stage are P2P application and content billing