A method and device for realizing look-up table processing

Abstract

A method and device for realizing table lookup processing, including: according to the key (KEY) value of the entry, determine whether the entry exists through cyclic redundancy check (CRC) polynomial calculation; when determining that the entry exists, determine the match according to the calculation result of the CRC polynomial Table address; according to the determined matching table address, the result returned after the matching table is checked, determines the off-chip hash (HASH) look-up address; according to the determined off-chip HASH look-up address, the look-up table is obtained to obtain the return of the hash look-up table KEY value, according to whether the KEY value of the entry is consistent with the KEY value returned by the hash lookup table, the table lookup process is performed. The method of the embodiment of the present invention reduces the entries that need to be looked up, reduces the occupation of pin resources and bandwidth resources, and avoids the impact on chip processing performance.

Description

technical field [0001] This article relates to, but is not limited to, data processing technology, especially a method and device for implementing table lookup processing. Background technique [0002] With the development of network technology, the number of related table entries that network switching chips need to support is increasing. Considering content addressable memory (CAM, content addressable memory) and ternary content addressable memory (TCAM, ternary content addressable memory) ) cost factor, in the case of large table entries, the related art generally uses an external double-rate synchronous dynamic random access memory (DDR) method to perform table lookup processing. [0003] Since the external DDR needs to consume more pin resources, the number of external DDR will be limited. When the number of DDR is limited, it is necessary to reduce the number of DDR accesses to prevent the hash (HASH) lookup table from being missed and appearing When multiple table lo...

AI Technical Summary

Problems solved by technology

[0003] Since the external DDR needs to consume more pin resources, the number of external DDRs will be limited. When the number of DDRs is limited, it is necessary to reduce the number of DDR accesses to prevent the hash (HASH) lookup table from failing, Multiple table lookups are required; if multiple table entries coexist in a group of DDRs, and different table entries need to be looked up multiple times, it will also need to occupy a huge DDR access bandwidth, which limits the efficiency of table lookups and blocks The processing of the chip greatly reduces the processing performance of the chip

[0004] To sum up, in the case of a large number of table entries, there are problems such as occupying too many pin resources, bandwidth resources, and affecting the processing performance of the chip when performing table lookup.

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