Multi-match 2-level hierarchical search method for ranges on basis of TCAM (ternary content addressable memory)

Abstract

The invention provides a multi-match 2-level hierarchical search method for ranges on the basis of a TCAM (ternary content addressable memory). The multi-match 2-level hierarchical search method is characterized by comprising extracting a wide interval range in a range set, and individually processing the wide interval range; merging relevant ranges of remaining ranges in the range set to the greatest extent so as to form a plurality of new range sets; dividing new ranges, which contain more than one original ranges, among new ranges into a plurality of contiguous ranges with mutual distance of 1; searching the merged new ranges in a first-level combination of the TCAM and an SRAM (static random access memory); judging to determine whether a second-level combination of the TCAM and the SRAM needs to be searched or not according to search results of new range sets so as to implement a multi-match technology for the ranges on the basis of the TCAM by two divided search procedures. The recombined new ranges are mostly formed by combining the original multiple original ranges. The multi-match 2-level hierarchical search method has the advantage that multi-match technology for the port ranges can be implemented for packet classification on the basis of the TCAM.

Description

technical field [0001] The present invention relates to a TCAM (Ternary Content Addressable Memory, three-state content addressable memory)-based two-level hierarchical search method for solving the multi-matching problem of ranges, which is mainly used in network devices such as intrusion detection systems, routers, and switches. The invention belongs to the technical field of network data packet classification in computer network. Background technique [0002] With the rapid development of network technology, especially the emergence of various new network applications in recent years, such as Network Intrusion Detection System (Network Intrusion Detection System, NIDS), Quality of Service (Quality of Service, QoS), Load Balance (Load Balance) ) and so on need to report all matching results or partial matching results. The traditional software-based packet classification technology is far from meeting the wire-speed requirements, but the hardware-based technology can solve...

AI Technical Summary

Problems solved by technology

[0004] TCAM can be used in packet classification technology mainly because it has the advantages of fast and accurate search speed, general structure and simple operation, but it also has several obvious disadvantages: high cost, high power consumption and complicated routing update

However, this method has disadvantages such as low search efficiency, the need to use extension bits, occupying additional TCAM space, low update efficiency, and the need to preprocess search keywords.

Chinese Patent: A Prefix Extension Method for Triple Content Addressable Memory Range Matching, Application No. 200610011517, Publication No. 101039253B, and Chinese Patent: Segmented Encoding Extension Method for Triple Content Addressable Memory Range Matching, Application No. 200610011465 , Publication No. 101035061B, proposed a prefix extension method and a segmented code extension method to solve the TCAM range matching problem, but these two methods still need several prefixes to replace a range, therefore, they cannot reduce the storage of TCAM very well In addition, if both the source port and the destination port are in the range, since the expansion number of the prefix is ​​the multiplication of the expansion number of the two port prefixes, a rule requires more TCAM entries to store, so it does not Applicable when the rule set contains many fields that contain multiple scopes at the same time

In addition, this paper does not use the idea of ​​TCAM partition search, but only searches all range sets in TCAM, so the search power consumption is much larger than that of the present invention

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