A hash method to calculate the longest prefix matching lpm rule index

Abstract

The invention discloses a hash method for calculating the index of the longest prefix matching LPM rule, which is characterized in that it includes the following steps: S1, ensuring that the storage structure of each storage unit storing the LPM rule is the same, and each storage unit can store 2 n rule, that is, each storage unit determines the position of the rule in the storage unit by n bits, and marks the length of its initial stored LPM rule for each storage unit; S2, when the LPM rule length L exceeds n, the Based on the previous n bits, XOR operations are performed bit by bit backward, and the cycle repeats until the hash value of the specified length of the LPM is calculated; S3. When the length L of the LPM rule does not exceed n, the hash value of the LPM rule is the LPM The first L position of the rule.

Description

technical field

[0001] The invention relates to the field of storage technology, in particular to a hash method for calculating the longest prefix matching LPM rule index. Background technique

[0002] Based on the rapid development of the current network era, each network node has greater requirements on the capacity of the LPM (Longest Prefix Match) rule. LPM rule storage can be implemented in a variety of hardware structures, but no matter which implementation method, in the face of massive LPM storage management and access, it is necessary to quickly index the specific location of the LPM rule, and the corresponding result of this rule has been obtained or how to handle it. In an environment with a large number of identical storage units, the degree of discrete storage rules determines the actual storage capacity of the LPM. Therefore, how to ensure the discrete distribution of LPM rules is the most important thing in storing LPM rules.

[0003] At present, the indust...

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