Efficient content addressable memory array for classless inter-domain routing
AssigneeSTMicroelectronics Pvt.Ltd.
InventorsDanish Syed, Rajiv Yadav, Anoop Khurana
Life of this patent
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Abstract
An efficient Content Addressable Memory array for Classless Inter-Domain Routing with each CAM cell including an additional storage unit for storing the prefix length associated with the contents of the cell. An enabling logic connects the prefix length value to a wired OR plane common to all CAM cells, and a sequential bit wise comparison unit has its inputs connected to the wired OR plane and the additional storage unit with its output controlling the enabling logic.
Claims16
1-8. (canceled)
A Content Addressable Memory (CAM) array for Classless Inter-Domain Routing (CIDR), the CAM array comprising:
- a plurality of CAM cells;
- and
- a wired OR plane connecting the plurality of CAM cells;
- a prefix length memory associated with each CAM cell to store a prefix length value associated with contents of the CAM cell;
- an enabling circuit connecting the prefix length memory to the wired OR plane common to all CAM cells;
- and
- a sequential bit-wise comparison unit having inputs connected to the wired OR plane and the prefix length memory, and an output controlling the enabling circuit.
A Content Addressable Memory (CAM) array comprising:
- a plurality of CAM cells;
- and
- a logic device connecting the plurality of CAM cells;
- a prefix length memory associated with each CAM cell to store a prefix length value associated with contents of the CAM cell;
- an enabling circuit connecting the prefix length memory to the logic device;
- and
- a comparison unit having inputs connected to the logic device and the prefix length memory, and an output controlling the enabling circuit.
A method for detecting a largest prefix length value among hit locations in a Content Addressable Memory (CAM) array including a plurality of CAM cells connected together via a logic device, the method comprising:
- storing, in a prefix length memory, the prefix length value associated with the contents of a respective CAM cell;
- selectively connecting the prefix length memory to the logic device common to all CAM cells;
- and
- comparing the stored prefix length value with a value on the logic device beginning from a most significant bit and disconnecting the prefix length memory based upon the comparison to provide the largest prefix length value.
Dependencies are inferred from the claim text.