Abstract: The present invention relates to a method for managing a plurality of multi-field classification rules. The method includes providing a first table that includes a plurality of entries corresponding to a plurality of rules relating to an ingress context and providing a second table that includes a plurality of entries corresponding to a plurality of rules relating to an egress context. The method also includes utilizing the first table and the second table to identify any rules relating to the ingress context and any rules relating to the egress context that match a search key.

Abstract: Method for compressing search tree structures used in rule classification is provided. The method includes classifying packets based on filter rules, compressing a tree structure comprising multiple levels of single bit test nodes and leaf nodes, storing the compressed tree structure in a first memory structure of a storage such that the multiple levels of single bit test nodes and leaf nodes can be accessed from the first memory structure through a single memory access of the storage, collecting single bit test nodes of the tree structure that are in a lowest level of the tree structure, storing only the collected single bit test nodes within a second memory structure of the storage that is contiguous to the first memory structure, collecting leaf nodes of the tree structure, and storing only the collected leaf nodes within a third memory structure of the storage that is contiguous to second memory structure.

Abstract: The present invention relates to a method and system for compressing a tree structure. The method of the present invention includes providing a compressed format block for representing a plurality of levels of the tree structure, where the plurality of levels comprises a set of nodes. The method also includes compressing each node in the set of nodes into the compressed format block, such that the plurality of levels is traversed in a single memory access.

Abstract: A technique is provided to either insert or delete a leaf in a Patricia tree having a direct table and a plurality of PSCB's which decode portions of the pattern of a leaf in the tree without shutting down the functioning of the tree. A leaf having a pattern is identified as either a leaf to be inserted or deleted. Using the pattern, the tree is walked once to identify the location of the leaf to be deleted or the location where the leaf is to be inserted. If it is a delete operation, the leaf to be deleted is identified and deleted, and any relevant PSCB modified, if necessary. If it is an insert operation, the tree is walked a second time to insert the leaf and reform or create any PSCB in the chain that needs to be reformed or created. The technique also is applicable to inserting or deleting a prefix of a prefix.

Abstract: A method and apparatus are used for finding the longest prefix match in a variable length prefix search when searching a direct table within a routing table structure of a network processor. The search through the routing table structure is expedited by hashing a first segment of an internet protocol address with a virtual private network number followed by concatenating the unhashed bits of the IP address to the result of the hash operation to form an input key. Patterns are compared a bit at a time until an exact match or the best match is found. The search is conducted in a search tree that provides that the matching results will be the best possible match.

Abstract: A tree structure and method to organize routing information for processing messages within a network, each message being associated with a search key of “n” bits. The processing determines where to send the message next. The structure has a direct table (DT) of 2x entries for decoding the first “x” bits of the search key, and one or more pattern search control blocks (PSCB's), each having 2m entries for decoding subsequent groups of “m” bits. Each PSCB entry and DT entry includes a pointer to data associated with a specific route, if at this point a specific routing table entry is a potential match to the search key or a pointer to a subsequent PSCB if the end of a search trail is not identified. Each PSCB entry DT entry also indicates that the search has been resolved to the end of the search trail.

Abstract: A method and apparatus are used for finding the longest prefix match in a variable length prefix search when searching a direct table within a routing table structure of a network processor. The search through the routing table structure is expedited by hashing a first segment of an internet protocol address with a virtual private network number followed by concatenating the unhashed bits of the IP address to the result of the hash operation to form an input key. Patterns are compared a bit at a time until an exact match or the best match is found. The search is conducted in a search tree that provides that the matching results will be the best possible match.

Abstract: A technique is provided to either insert or delete a leaf in a Patricia tree having a direct table and a plurality of PSCB's which decode portions of the pattern of a leaf in the tree without shutting down the functioning of the tree. A leaf having a pattern is identified as either a leaf to be inserted or deleted. Using the pattern, the tree is walked once to identify the location of the leaf to be deleted or the location where the leaf is to be inserted. If it is a delete operation, the leaf to be deleted is identified and deleted, and any relevant PSCB modified, if necessary. If it is an insert operation, the tree is walked a second time to insert the leaf and reform or create any PSCB in the chain that needs to be reformed or created. The technique also is applicable to inserting or deleting a prefix of a prefix.

Abstract: A structure and method of routing a message is disclosed. A tree structure is provided for organizing routing information used in processing messages within a network, each message being associated with a search key of “n” bits. The processing includes a determination of where to send the message next to get the message closer to the desired destination. The structure has a direct table (DT) of 2x entries for decoding the first “x” bits of the search key. One or more pattern search control blocks (PSCB's), each having 2m entries for decoding subsequent groups of “m” bits, is provided. Each PSCB entry and DT entry includes a pointer to data associated with a specific route, if at this point a specific routing table entry is a potential match to the search key. Each PSCB entry and DT entry includes a pointer to a subsequent PSCB if the end of a search trail is not identified.