Method and apparatus processing of message data

A method of header processing, in a system comprising a context memory storing a plurality of rules, each said rule comprising one or more field instructions, each said field instructions comprising a target value and a processing instruction;

• a header compression processor adapted to determine for each said rule whether a respective specified region of a data message corresponds to said target value in a respective prescribed manner, and in a case where said respective specified region corresponds to said target value in said respective prescribed manner for each field instruction line in a respective said rule, applying the processing instruction of each field instruction line in a corresponding rule with regard to the respective specified region, wherein a data component processed is defined by said processing instruction,
• said method comprising:
• assessing a processing context,
• providing one or more instructions defining an operation of said header compression processor as a function of said processing context, and
• performing one or more header compression operations in accordance with said instruction,
• wherein said data message belongs to one of a plurality of data flows processed by said header processing system, and said processing context comprises an identity of a data flow to which said data message belongs, and
• wherein a controller is adapted to determines that available compression rules in the context memory are not well suited to characteristics of an incoming stream to generate a new rule with regard to historical content of said data message, where said new rule or modified rule provides a compression operation optimized for said historical content, and to provide one or more said instructions to said context memory to modify the content thereof by adding said new rule thereto.