TCAM BIST with redundancy
AssigneeHewlett-Packard Development Company, L.P.
InventorsJohn A. Wickeraad, Jonathan E. Greenlaw
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Abstract
In an embodiment of the invention, a method of providing redundancy in a ternary content addressable memory (TCAM) includes: detecting a defective entry in a ternary content addressable memory (TCAM); marking the defective entry so that the defective entry is visible to a software; and avoiding in using the defective entry. For data that normally would have been written into the defective entry, the data is written into an entry that is subsequent to the defective entry. In another embodiment, the redundancy is provided in a CAM instead of a TCAM.
Claims17
A method of providing redundancy in a ternary content addressable memory (TCAM), the method comprising:
- detecting a defective entry in building block in a ternary content addressable memory (TCAM);
- writing an address of the defective entry into a storage area;
- and
- setting a bit associated with the address in order to indicate that the entry is defective.
An apparatus for providing redundancy in a ternary content addressable memory (TCAM), the apparatus comprising:
- a ternary content addressable memory (TCAM) comprising at least one building block and at least one storage area,, wherein an address of a defective entry is written into said storage area and a bit associated with the address is set in order to indicate that the entry is defective;
- and
- a remapping table configures to redirect a query that is directed to the defective entry to another entry.
A ternary content addressable memory (TCAM) device comprising:
- at least one building block;
- at least one storage area, wherein an address of a defective entry detected in said at least one building block is written into said at least one storage area;
- and
- a bit associated with said address, wherein said bit is set in order to indicate that the entry is defective.
Dependencies are inferred from the claim text.