Packet switching system for a communication network node

Switching system for a communication network node, comprising several input modules (IMi, IM2, IMi, IMn) each connected to a switching matrix (1) and to a controller (2) controlling the said matrix (1), the said system being capable of switching flows of data packets received by the said input modules, selectively as a function of their corresponding destinations, to destination output ports (OP1, 0P2, OPj, OPn), each input module (IMi) comprising means (9, 10) for processing received packets, these means (9, 10) being designed to organize these packets into digital data blocks (IBi), each of these blocks having a fixed size, and to make transfers of these blocks to the matrix (1) by successive cycles, characterized in that each of these blocks (IBi) is organized into groups of digital data (DGi1, DGi2, DGij, DGin), these groups being stored according to a predetermined order and each associated with the said output ports, each of these groups being formed of digital data belonging to one or several packets to be sent to the said associated output port, in that the said groups have corresponding modifiable sizes, in that any block transfer to the matrix (1) is accompanied by transmission of information representative of the corresponding sizes of the said groups of the transferred block to the said controller (2), and in that the groups of each transferred block are switched to their corresponding destination output ports, these output ports being identified using the said information representative of the size of each of the said transferred block groups.