Method for quickly searching keywords and reading lists by using ternary content addressable memory (TCAM)

Abstract

The invention discloses a method for quickly searching keywords by using a ternary content addressable memory (TCAM). In the process of searching the keywords by using the TCAM, the keywords are placed on one or more TCAMs according to the types and bits of the keywords, and a mapping relation between the TCAMs and system random access memories (SRAMs) is formed by using a configuration register,so that addresses which are searched from the TCAMs are allocated to any one SRAM under the logic control of the configuration register, the keywords can be concurrently searched on the TCAMs, and data in the SRAMs can be concurrently read. By the method, the keywords with different bit widths and different types can be placed on the same TCAM at the same time by making full use of TCAM and SRAM resources, the keywords and corresponding list items can be flexibly configured in the TCAMs and the SRAMs, the list searching efficiency of a switch chip is improved, and the area and the power consumption of the chip are reduced under the condition of guaranteeing the universal list searching performance.

Description

technical field [0001] The invention relates to computer network technology, in particular to a method for quickly searching different kinds of different bit keys (Keys) by using TCAM in an Ethernet switch chip. Background technique [0002] In an Ethernet switch chip, functions such as fast searching of ACL (Access Control List, access control list) and routing table are often involved, and the search efficiency will affect the performance of the chip at this time. TCAM (Ternary Content Addressable Memory, ternary content addressable memory) has the characteristics of fast parallel search and simple access mode, which is very suitable for this occasion. However, TCAM has the disadvantages of high cost and high power consumption at the same time, which restricts its large-scale use in chips. After the table lookup is completed, it is usually necessary to read the entry in the SRAM corresponding to the address according to the address retrieved by the TCAM. There are more a...

AI Technical Summary

Problems solved by technology

If the lookup table of a certain type or size of keywords does not use up the current TCAM, waste will be generated

And it will lead to a waste of SRAM for storing representations

If the ACL is searched many times, multiple indexes (index) are obtained to access the SRAM serially, so the reading of data in the SRAM will become a bottleneck, affecting the overall performance of the chip

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