An object is to create a convergent mediation system (10) and method that meet the technical requirements of low latency time and high reliability. According an aspect of the invention, these objects are achieved by providing a convergent mediation system (10) that comprises a plurality of independent processing nodes (120, 125) adapted to form processing streams (200) for the online processing (12) and off-line processing (14) of data. Each of the processing streams (200) comprises at least two independent nodes (120, 125) in sequence and buffers (145) between the nodes (120, 125). Furthermore, random access memory is utilized such that at least one of the buffers (145) in each of the online processing streams (212) is formed by a dedicated memory area in the random access memory.