Cascadable content addressable memory (CAM) device and architecture
AssigneeCypress Semiconductor Corporation
InventorsDavid V. James, Jagadeesan Rajamanickam
Life of this patent
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Abstract
According to one embodiment, a CAM system (100) may include a plurality of CAM devices (102-0 to 102-n) arranged in cascade configuration. A CAM system (100) may include an input connection (104) that receives a request to perform a particular operation and an output connection (106) on which a CAM system (100) may provide a single response based on responses from each CAM device (102-0 to 102-n). In one particular approach, a request may flow through CAM devices (102-0 to 102-n) in a single direction from a first CAM device (102-0) to a last CAM device (102-n). Similarly, responses to requests may be generated in the same direction, from a first CAM device (102-0) to a last CAM device (102-n).
Claims19
A content addressable memory (CAM) system comprising:
- a plurality of content addressable memory (CAM) devices arranged in a series including a first CAM device having at least one input port for receiving an operation request and a last CAM device having at least one output port for providing a response to the operation request based on responses for the plurality of CAM devices;
- wherein
- each CAM device includes a first vote portion that generates a first vote output response from a local response generated by a search portion internal to the CAM device and a remote response received at the at least one input port of the CAM device, the first vote portion generates a first vote output response according to at least predetermined precedence data associated with each response.
A content addressable memory (CAM) device, comprising:
- a search portion that receives an operation request and generates a local response to the operation request;
- and
- at least a first vote portion that generates a fist vote output response from the local response and a remote response to the same operation request received at an input port of the CAM device and includes a vote circuit that selects between the local response and remote response according to predetermined precedence values.
A method of operating content addressable memory (CAM) devices in a CAM system, comprising the steps of:
- applying an operation request to a plurality of CAM devices arranged in series in a single direction relative to the series arrangement;
- and
- generating responses to the operation request in the single direction;
- wherein
- applying the operation request includes branching an operation request with a branching CAM device that receives the operation request at an input port of the branching CAM device and provides the response to at least two output ports of the branching CAM device.
A content addressable memory (CAM) system, comprising:
- a host processing component;
- and
- at least one CAM component having a vote circuit that selects one of a plurality of search status result values based on a comparison between a remote search result generated by another CAM component and a local search result generated by the at least one CAM component, each search status result value having a predetermined precedence with respect to one another.
Dependencies are inferred from the claim text.