1. A method comprising: (a) writing a first search key data set and a second search key data set into a memory, wherein the memory is written with search key data sets only on a word by word basis, wherein each of the first and second search key data sets includes a header along with a string of search keys, wherein the header of a search key data set indicates a common lookup operation to be performed using each of the search keys of the search key data set, wherein the header of a search key data set is immediately followed in memory by a search key of the search key data set, wherein the search keys of the search key data set are located contiguously in the memory, and wherein at least one word contains search keys from both the first and second search key data sets; (b) reading the memory word by word and thereby reading the first search key data set and the second search key data set; (c) outputting a first plurality of lookup command messages, wherein each respective one of the first plurality of lookup command messages includes a corresponding respective one of the search keys of the first search key data set; and (d) outputting a second plurality of lookup command messages, wherein each respective one of the second plurality of lookup command messages includes a corresponding respective one of the search keys of the second search key data set.