System and method for algorithmic TCAM packet classification

摘要

In a Ternary Content Addressable Memory (TCAM) optimized for network packet classification, network operation rules are preprocessed into sub-lists in accordance with a decision tree based packet classification algorithm. The decision tree is encoded as a lookup memory, which is accessed with a predetermined base address of higher order address bits combined with lower order address bits obtained from specific bit positions from a received network packet. Depending on the nodes traversed in the decision tree, different base addresses and values from different bit positions of the packet are used until a sub-list of potential rules is identified. A bitwise comparison of values of each rule against the packet is then executed, the matching rule with the highest precedence is returned as the matching table entry and the configured value associated with the entry is prepended to the packet.