US 6930978 System and method for traffic management control in a data transmission network

ABSTRACT – A traffic management system sniffs data arriving at any point in a system. The sniffer operates to remember certain parameters pertaining to the data. When the amount of data arriving at the point begins to reach a critical level (usually dependent upon data processing capability associated with that point), the system begins to remove (and share) subsequent arriving data based, in part, upon the remembered parameters of recently received data. Data that is stored is returned to the system when the critical threshold recedes.


This invention relates to data network control systems and more particularly to a system and method for monitoring and filtering traffic to maintain a constant stream of data flowing in and/or out of a particular location.


Data flow in and out of a data source is vital to the proper operation of many enterprises. When this data flow is interrupted, even for the briefest of intervals, a major problem exists. One way to interrupt such data flow is by flooding any communication line (or any network device on the pathway) with so many data packets that the device simply clogs and ceases to function properly. In such a situation, data can be lost, transactions not completed and the flow of commerce halted.

Companies are getting attacked via data flooding by a wide range of flooding mechanisms, including certain types of Denial of Service (DOS) and Distributed Denial of Service (DDOS) attacks that are not specific to an application, but exist in the network.

One known solution to this particular type of problem is manual intervention by a system administrator scrolling on access control list screen to manually select and block an offending IP address.

This, of course, presupposes that the operator even knows which sending IP address(es) is causing the problem. If the rogue sending address keeps changing, the operator (system administrator) is at a loss. The other solutions that we know of are remote intrusion detection sensors that provide manual notification that an attack has been detected and lists the known offending IP address. A third solution is remote monitoring of network conditions. The problem with the solutions to date is the fact that by the time a human can respond to the existing condition, it is already beyond his/her ability to control the traffic and the network is brought down by the intruding traffic overload.

For example, today even assuming a modest speed of, let’s say a 1,000 packet/second, about half of the maximum data rate of a T1 channel, the human eye cannot respond that fast to read the IP addresses, digest the information and act before many, many packets enter the system and cause damage. Today a typical enterprise can receive a million hits in an hour, made up of perhaps 4,000,000 or 5,000,000 packets. Such large numbers of packets, when backed up, cause the system to stop functioning.


The present invention includes a system which implements a three tiered architecture where the database runs on one computer, or across multiple computers, and the kernel and all of its intelligence runs on a separate computer while the applications and management tools run on other computer(s). The system is designed to monitor every tcp/ip packet directed toward a company and to keep track of each packet from each IP address, including all of the bytes of information associated with each packet. The goal of the system and method is to prevent flooding which is defined as a threshold above which data throughput must not go.

If desired, the system can have several threshold’s, each dynamically changeable, when a threshold is reached. Threshold, in this context, means that the number of arriving data packets and the accumulated number of bytes of information during a preset time period, (called a primary time slice (PTS)) has met a limit. When this happens certain packets are scanned, captured, and prevented (temporarily) from passing through the system. When the traffic rate falls to the threshold level these captured packets are allowed to then flow through the system. The captured packets are selected based on a comparison of information “sniffed” by the monitor against certain criteria, such as number of packets and the accumulation of bytes per PTS coming from a particular IP address; a known “bad” IP address; and known bad data patterns.

Generally, when it comes to flooding, there are four (or more or less) threshold levels which exist which are percentages of the total maximum band-width of the network. The thresholds can be for example 20, 30, or 40 percent of maximum. If the traffic flow is under the lowest threshold, everything runs smoothly. Once the number of arriving packets and accumulated bytes violate a threshold, the system begins, automatically, the process of choking or holding certain packets. If higher thresholds are violated then more and more severe action is taken, i.e. more and more packet(s) are prevented from flowing through the system.

One embodiment of the system includes several real time displays, or tools, to analyze, manage, and monitor the data bases, the kernel, and the whole system. One visual display of data and addresses shows the packets that have been choked and, optionally could show why. This information can be displayed locally and can be communicated remotely to any terminal or communication device anywhere in the world. Thus, a user, operating from any terminal with the appropriate user ID and password can make adjustments to the system by changing the different parameters allowing more or less data flow. The operator can, if desired, adjust the criteria for choking data.

The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims. The novel features which are believed to be characteristic of the invention, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present invention.


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