Abstract: A Route Lookup Engine (RLE) for determining a next hop index is disclosed. The RLE receives a lookup key and performs a multi-bit trie search with prefix expansion and capture of a variable stride trie. The data that the RLE returns comprises the next hop information and status flags. The RLE uses a compact, field reusable data structure. The RLE performs both unicast and multicast IP address lookups on Virtual Private Networks. The RLE uses separate indexing and forwarding memories. The upper bound of the search time for the RLE is fixed regardless of the route table size.

Abstract: Packet classification apparatus includes a rule memory and a criterion memory. One type of rule memory entry contains an operator and a pointer to a criterion memory entry. The operator defines a comparison operation to be performed, such as EQUAL (exact match) or LESS THAN. The criterion memory entry contains one or more values to be used as comparands on one side of the comparison, where corresponding values from a received packet appear on the other side of the comparison. Control logic responds to packet classification requests to retrieve a rule memory entry from the rule memory, retrieve the criterion memory entry identified by the criterion memory pointer in the rule memory entry, and perform the operation specified by the operator in the rule memory entry on the values in the criterion memory entry and corresponding values included in the classification request.

Abstract: Packet processing logic includes a request queue for receiving lookup requests from a packet processor, where each request includes information elements from a received packet and indicates that a route lookup and a packet classification are to be performed based on the information elements. Both a route lookup engine (RLE) and a packet classification engine (PCE) have respective inputs coupled to the request queue for receiving selected information elements from the requests. Based on the information elements in each request, the RLE searches for forwarding information indicating how the packet corresponding to the request should be forwarded, and the PCE performs a classification process and generates classification information about the packet corresponding to the request. For each request, the forwarding information from the RLE and the classification information from the PCE are combined into a single result stored in a result queue.