Abstract: A switching device for forwarding network traffic to a desired destination on a network, such as a telephone or computer network. The switching device includes multiple ports and uses a lookup table containing lookup keys to determine which port to forward network traffic over. The lookup tables are populated based on use. Consequently, the lookup tables on different ports contain different addresses. By storing only addresses that a port uses, each port's lookup table is unique to that port's characteristics. Additionally, aging techniques are used on both source and destination addresses in the lookup table so that stale entries are removed and memory is conserved.

Abstract: Multiple lookup engines stacked upon one another in a single data communication switch. The lookup engine at the top of the stack transmits its result to the neighboring downstream lookup engine which either validates and transmits the received result or its own result based on the quality of its match. The result preferably indicates an exact match, partial match, or no match. Although several lookup engines can return a partial match, an exact match preferably occurs in only one lookup engine. The comparison, validation, and transmission steps are repeated by each downstream lookup engine, with the lookup engine at the bottom of the stack validating and returning a final result to the packet processor. The returned final result reflects a search result with the highest match quality.

Abstract: A congestion control method and apparatus in a cell-switched data switch. The switch attaches a tag with a discard processing indicator, such as a particular random number, to all cells belonging to a same packet. In determining which cells to drop when running a congestion control algorithm such as RED, the switch compares the discard processing indicator of the cells with a discard criterion and only drops cells that conform with the discard criterion.