1. A method for updating a dynamic dictionary for use in compressions and decompressions of messages, the method comprising the steps of: a. receiving at a compression/decompression module in a networking node a message containing individual expressions; b. determining at the compression/decompression module all matches between the individual expressions of the message and corresponding expressions in a first dictionary stored in a memory; c. among the determined matches of individual expressions, determining different sequences of matches of individual expressions which are contiguous to each other in the message, each of the different matching sequences including one or more contiguous individual expressions and the different sequences which are determined to be contiguous to each other forming at least one new combined expression; and d. creating in the dynamic dictionary the at least one new combined expression for exclusive use by the compression/decompression module.