CONCURRENT ERROR DETECTION IN A TERNARY CONTENT-ADDRESSABLE MEMORY (TCAM) DEVICE

摘要

A plurality of data words are written into a TCAM; each has binary digits and don't-care digits. Contemporaneously, for each of the words: a first checksum is calculated on the binary digits; and the following are stored in a corresponding portion of a RAM: an identifier of the binary digits and the first checksum. The ternary content-addressable memory is queried with an input word. Upon the querying yielding a match, further steps include retrieving, from the random-access memory, corresponding values of the identifier of the binary digits and the first checksum; computing a second checksum on the input word, using the identifier of the binary digits; and if the second and first checksums are not equal, determining in real time that the match is a false positive.

主权项

1. A method comprising:
writing a plurality of data words into a ternary content-addressable memory, each of said data words having binary digits and don't-care digits; contemporaneous with said writing, for each of said plurality of data words:
calculating a first checksum on said binary digits;storing, in a corresponding portion of a random-access memory:
an identifier of said binary digits of said corresponding one of said data words; andsaid first checksum for said corresponding one of said data words; querying said ternary content-addressable memory into which said plurality of data words have been written with an input word; upon said querying yielding a match:
retrieving from said random-access memory, corresponding values of said identifier of said binary digits and said first checksum;computing a second checksum on said input word, using said identifier of said binary digits; andif said second and first checksums are not equal, determining in real time that said match is a false positive.