Flow key lookup involving multiple simultaneous cam operations to identify hash values in a hash bucket

A method comprising:

• (a) determining a hash value A and a hash value B from a flow key, wherein the flow key comprises at least a portion of an IP source address of a packet, at least a portion of an IP destination address of the packet, at least a portion of a TCP source port of the packet, and at least a portion of a TCP destination port of the packet;
• (b) using the hash value A to identify a hash bucket in a hash table, wherein the hash bucket includes a plurality of hash bucket entry fields, wherein the hash bucket further comprises a set of flag bits for each of the hash bucket entry fields, wherein the hash value B is stored in at least one of the hash bucket entry fields of the hash bucket;
• (c) performing a (Content Addressable Memory) CAM lookup operation on a content of each of the hash bucket entry fields thereby generating a CAM lookup output value for each of the hash bucket entry fields, wherein (c) involves performing a plurality of simultaneous CAM lookup operations, wherein the CAM lookup output values generated in (c) identify which one or ones of the hash bucket entry fields store the hash value B, and wherein the CAM lookup output values generated in (c) also include the flag bits for each hash bucket entry field that stores the hash value B;
• (d) using the CAM lookup output values generated in (c) to identify one or more flow keys stored in a key table, wherein each identified flow key corresponds to a hash bucket entry field that stores the hash value B, and wherein each flow key stored in the key table has a corresponding lookup output information value;
• (e) determining which one of the flow keys identified in (d) matches the flow key in (a);
• (f) using flag bits of the CAM lookup output values generated in (c) to determine an action to perform on the packet;
• and
• (g) performing the action determined in (f) on the packet, wherein (a) through (g) are performed by a device that performs actions on packets.

A network appliance comprising:

• a processing circuit adapted to determine a hash value A and a hash value B from a flow key, wherein the flow key comprises at least a portion of an IP source address of a packet, at least a portion of an IP destination address of the packet, at least a portion of a TCP source port of the packet, and at least a portion of a TCP destination port of the packet;
• means for (a) using the hash value A to identify a hash bucket in a hash table, wherein the hash bucket includes a plurality of hash bucket entry fields, wherein the hash bucket further comprises a set of flag bits for each of the hash bucket entry fields, wherein the hash value B is stored in at least one of the hash bucket entry fields of the hash bucket, and wherein the means is also for (b) performing a (Content Addressable Memory) CAM lookup operation on a content of each of the hash bucket entry fields thereby generating a CAM lookup output value for each of the hash bucket entry fields, wherein the performing of the CAM lookup operation involves performing a plurality of simultaneous CAM lookup operations, wherein the CAM lookup output values generated identify which one or ones of the hash bucket entry fields store the hash value B, and wherein the CAM lookup output values generated also include the flag bits for each hash bucket entry field that stores the hash value B;
• and
• a storage mechanism that stores at least a part of a key table, wherein the network appliance uses the CAM lookup output values to identify one or more flow keys stored in the key table, wherein each identified flow key corresponds to a hash bucket entry field that stores the hash value B, wherein each flow key stored in the key table has a corresponding lookup output information value, and wherein the network appliance also identifies which one of the flow keys in the key table matches the flow key from which the hash values A and B were determined.