Method and apparatus for a flexible and reconfigurable packet classifier using content addressable memory
First Claim
1. A method of classifying packet information using content addressable memory (CAM), the method comprising the step of:
- receiving a set of reconfigurable selection criteria from a user wherein said set of selection criteria is limited by CAM constraint.
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Abstract
The present invention provides for a reconfigurable packet classifier using CAM. The invention is directed to packet classification for switching/routing systems where the router'"'"'s system resources are limited and the customer requirements from the router are variable. The invention addresses the CAM constraint (e.g. search key width) problems of CAM-based classification systems, by allowing a reconfigurable selection of packet fields and/or payload bits to be used in the definition of the search key. For any given incoming packet, a subset of that incoming packet may be statically chosen to fit that particular CAM architecture and to create a particular CAM search key. This provides router deployment flexibility within networks and, thus, cuts costs.
221 Citations
38 Claims
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1. A method of classifying packet information using content addressable memory (CAM), the method comprising the step of:
receiving a set of reconfigurable selection criteria from a user wherein said set of selection criteria is limited by CAM constraint. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A content addressable memory (CAM) controlling hardware wherein said CAM controlling hardware
receives a set of reconfigurable selection criteria from a user wherein said selection criteria is limited by CAM constraint.
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19. A packet classifier system comprising:
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a content addressable memory (CAM) controlling hardware that generates a CAM search key based on a set of reconfigurable selection criteria provided by a user and a bit mask generated at run time based on the packet structure of a packet information received; and
a packet memory.
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20. A router or switch comprising
an integrated circuit containing a content addressable memory (CAM) controlling hardware which interfaces with an ingress manager by receiving packet information, which interfaces with a CAM to do a search or lookup on the classification database contained in said CAM, which interfaces with an action content database (RAM/Memory) to do a memory read, and which interfaces with an egress manager which sends out packet information.
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21. A method of enabling a user to reconfigure a router or switch, the method comprising:
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providing a user interface wherein said user is able to define a set of reconfigurable selection criteria to determine a CAM search key; and
receiving said selection criteria. - View Dependent Claims (22, 23, 24, 25, 26, 28, 29, 30, 31, 32)
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27. A computer software product for use in a computer system that executes program steps recorded in a computer-readable media to perform a method for enabling a user to reconfigure a router or switch, the method comprising:
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a) a recordable media; and
b) a program of computer-readable instructions executable by the computer to perform method steps comprising;
i) providing a user interface wherein said user is able to define a set of reconfigurable selection criteria to determine a CAM search key; and
ii) receiving said selection criteria.
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33. An apparatus that enables a user to reconfigure a router or switch, the method comprising:
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a) a central processing unit;
b) a storage device;
c) a processor connected to the storage device wherein the storage device stores;
i) at least one program component for controlling the processor; and
d) the processor is operative with said program component to;
i) provide a user interface wherein said user is able to define a set of reconfigurable selection criteria to determine a CAM search key; and
ii) receive said selection criteria. - View Dependent Claims (34, 35, 36, 37, 38)
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Specification