They attempt to mitigate the collision problem by introducing a random distributed selection of a hash function from the universal set, and then applying it to the IP address. In either hashing scenario, the source address and the hash are mapped together in a table for later look-up along with a bit indicating which portion of the address they have received. Through a complicated procedure and a random hash selection, they are capable of reducing address collision. By using a deterministic approach they reduce the time for their reconstruction procedure for their mark (the 16-bit hash). However, by encoding that mark through hashing they introduce the probability of collisions, and thus false-positives.