Hash-based method for searching CAM (central address memory)

Abstract

The invention provides a hash-based method for searching a CAM (central address memory). The CAM has a data storage function and a high-speed data content searching function and also supports multiple instructions such as reading, writing and searching. However, the most important function of the CAM is the high-speed data content searching function, and the searching function is based on other functions of the CAM. Therefore, the core of the design of a CAM functional model is the design of a high-speed searching engine. The searching engine can maintain a sheet and receive external input data. The input data and each item in the sheet are completely compared (accurate) or partially compared (Don'tcare function) through a certain search algorithm in the searching engine, and then comparison results are output. The rapid CAM content search can be achieved via a hash function. When a request is searched through the CAM, hash calculation is carried out for data to be searched to obtain a hashkey, a first address of a CAM table item data linked list is obtained via access to a hash entry table according to the hashkey (as a hash entry table address), the access to the CAM data table item linked list is completed, the data to be searched and items in the CAM data linked list are compared one by one, and finally CAM search results are returned.

Description

[0001] technical field [0002] The invention relates to the technical fields of communication, data searching and matching under high-speed network or chip design, and specifically relates to a method for searching CAM based on Hash. Background technique [0003] With the rapid development of communication technology, on the one hand, the data bandwidth transmitted in the network is getting larger and larger. On the other hand, various applications in the network are constantly changing and developing. The current IP network needs to provide users with more service types and better service quality, requiring routers to provide additional processing mechanisms to achieve differentiated services. Classification, security intrusion monitoring, firewall access control, virtual private network, fast route lookup, network address translation, and some other key network technologies. [0004] In order to adapt to the growing trend of network data traffic and ensure the smoothness...

AI Technical Summary

Problems solved by technology

With the development of network technology, these key network technologies all involve search and match problems, but the efficiency of search and match based on software is low, and the traditional software implementation method is obviously insufficient for the development of high-speed networks.

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