Lookup processing implementation method and device

Abstract

The invention discloses a lookup processing implementation method and device. The method comprises the steps that according to a KEY value of an entry, whether the entry exists is determined through calculation according to a cyclic redundancy check (CRC) polynomial; when it is determined that the entry exists, a matching table address is determined according to the calculation result of the CRC polynomial; according to a result returned after lookup is performed on a matching table according to the determined matching table address, an off-chip HASH lookup address is determined; and lookup isperformed according to the determined off-chip HASH lookup address to obtain a HASH lookup return KEY value, and lookup processing is performed according to the judgment of whether the KEY value of the entry and the HASH lookup return KEY value are consistent. Through the method in the embodiment, entries needing lookup are reduced, occupation of pin resources and bandwidth resources is lowered,and the influence on chip processing performance is avoided.

Description

technical field [0001] This article involves but is not limited to data processing technology, especially a method and device for realizing look-up table processing. Background technique [0002] With the development of network technology, the number of related entries that network switching chips need to support is increasing. Considering content addressable memory (CAM, content addressable memory) and tri-state content addressable memory (TCAM, ternary content addressable memory) ) cost factor, in the case of large table entries, related technologies generally use an external double-rate synchronous dynamic random access memory (DDR) to perform table lookup processing. [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 ta...

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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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