Method and apparatus for using ternary and binary content-addressable memory stages to classify packets

A system for classifying a set of information, the system comprising:

• a ternary content-addressable memory configured to receive the set of information, and to perform a lookup operation with a search key based on the set of information to produce a first result;
• a table configured to receive the first result and to produce a second result based on the first result as an index into the table;
• a mask generator configured to receive the second result and to produce a third result;
• a hash function configured to receive the third result and to produce a fourth result based on the third result used as a hashing key;
• and
• a binary content-addressable memory configured to receive the fourth result and to perform a lookup operation with a search key based, on the fourth result to produce one or more classification indications.

A method for classifying a set of information, the method comprising:

• a ternary content-addressable memory receiving the set of information;
• the ternary content-addressable memory performing a lookup operation with a search key based on the set of information to produce a first result;
• generating a second result from the first result, wherein said generating the second result from the first result includes performing a memory lookup and a mask generation;
• a binary content-addressable memory receiving the second result derived from the first result;
• and
• the binary content-addressable memory performing a lookup operation with a search key based on the second result to generate one or more classification indications.

A method for classifying a set of information, the method comprising:

• a ternary content-addressable memory receiving the set of information;
• the ternary content-addressable memory performing a lookup operation with a search key based on the set of information to produce a first result;
• generating a second result from the first result, wherein said generating the second result from the first result includes performing a memory lookup, a mask generation and a hashing operation;
• a binary content-addressable memory receiving the second result derived from the first result;
• and
• the binary content-addressable memory performing a lookup operation with a search key based on the second result to generate one or more classification indications.

A method for classifying a set of information, the method comprising:

• a ternary content-addressable memory receiving the set of information;
• the ternary content-addressable memory performing a lookup operation with a search key based on the set of information to produce a first result;
• generating a second result from the first result, wherein said generating the second result from the first result includes performing a memory lookup and a hashing operation;
• a binary content-addressable memory receiving the second result derived from the first result;
• and
• the binary content-addressable memory performing a lookup operation with a search key based on the second result to generate one or more classification indications.

A system for classifying a multicast packet, the system comprising:

• a ternary content-addressable memory configured to receive a flow label including a source address and a group address of the multicast packet, and to perform a lookup operation with a search key based on the flow label to produce a first lookup result;
• a flow class table configured to receive the first lookup result and to produce a classification indication using an index into the flow class table, the index being identified based on the first lookup result;
• a mask generator configured to receive the classification indication and to generate a masked fields indication based on the classification index;
• a hash function configured to generate a hashing key based on the flow label and the masked fields indication, and to produce a hashed value based on the hashing key;
• and
• a binary content-addressable memory configured to receive the hashed value and to perform a lookup operation with a search key based on the hashed value to produce a classification indication of the multicast packet.