Method and apparatus for determining precedence in a classification engine
View Patent ↗A precedence determination system including a first type memory bank configured to receive a first search signal and to provide first search result indications, a second type memory bank configured to receive a second search signal and to provide second search result indications, a precedence number table coupled to the first and second type memory banks and configured to provide programmable precedence numbers, and a precedence determination circuit coupled to the first and second type memory banks and the precedence number table and configured to provide a third search result indication is disclosed. In one embodiment, the first type memory bank can be a static random access memory (SRAM) and the second type memory bank can be a ternary content addressable memory (TCAM).
1. A precedence determination system, comprising:
a precedence number table coupled to first and second type memory banks and providing a plurality of programmable precedence numbers; and
a precedence determination circuit coupled to the first and second type memory banks and the precedence number table and providing a search result indication.
2. The precedence determination system of claim 1 , wherein;
the first type memory bank includes static random access memory (SRAM).
3. The precedence determination system of claim 1 , wherein:
the second type memory bank includes ternary content addressable memory (TCAM).
4. The precedence determination system of claim 2 , wherein:
the first type memory bank includes a plurality of entries.
5. The precedence determination system of claim 3 , wherein:
the first type memory bank includes a plurality of entries.
6. The precedence determination system of claim 1 , wherein:
a search signal received by the first type memory bank includes a hash function signal
7. The precedence determination system of claim 1 , wherein:
a search signal received by the second type memory bank includes a search key.
8. The precedence determination system of claim 4 , wherein:
each of the plurality of entries is configured to select one of the plurality of programmable precedence numbers.
9. The precedence determination system of claim 5 , wherein:
each of the plurality of entries is configured to select one of.the plurality of programmable precedence numbers.
10. The precedence determination system of claim 6 , wherein:
each of a plurality of search result indications provided by the first type memory bank includes a hit or miss indication in response to the hash function .signal.
11. The precedence determination system of claim 7 , wherein:
each of a plurality of search result indications provided by the second type memory bank includes at most one hit indication in response to the search key.
12. The precedence determination system of claim 11 , wherein:
the at most one hit indication is provided in response to a physical address based precedence.
13. The precedence determination system of claim 1 , wherein:
the search result indication includes an overall hit or miss indication.
14. The precedence determination system of claim 13 , wherein:
the overall miss indication includes a default precedence value.
15. A method of determining a precedence, comprising:
providing at least one first search result;
providing at least one second search result;
selecting a plurality of precedence numbers from a precedence number table in response to the first and second search result;
determining a precedence in response to the plurality of precedence numbers; and
providing a third search result.
16. The method of determining the precedence of claim 15 , wherein:
a first type memory searched to provide the at least one first search result includes static random access memory (SRAM).
17. The method of determining the precedence of claim 16 , wherein:
a second type memory searched to provide at least one second search result includes ternary content addressable memory (TCAM).
18. The method of determining the precedence of claim 15 , further comprising:
searching a first type memory and searching a second type memory substantially in parallel.
19. The method of determining the precedence of claim 15 , wherein:
the third search result includes an overall hit or miss indication.
20. The method of determining the precedence of claim 19 , wherein:
the overall miss indication includes a default precedence value.
21. The method of determining the precedence of claim 15 , wherein:
the plurality of precedence numbers are programmable.
22. An apparatus for determining a precedence, comprising:
a means for providing at least one first search result;
a means for providing at least one second search result;
a means for selecting a plurality of precedence numbers from a precedence number table in response to the first and second search result;
a means for determining a precedence in response to the plurality of precedence numbers; and
a means for providing a third search result.