Fast and robust TCP session lookup by digest hash

We present a new design for fast and robust TCP session lookup. The design uses a "set-associative" hash table, where each hash bucket keeps multiple "compressed and canonical" tags. The canonical tags encode both the flow identifiers and the addresses of the TCP contexts by a forward signature function F(Tag(flow identifier), address) during installation. On session lookup, an inverse function F^I (Tag(flow identifier), tag) matches sessions and recovers the address of the TCP context. We show that the method is effective and storage-efficient. It is also resistant to denial-of-service attack that is fabricated by forcing excessive hash collisions