Abstract: An arrangement and a method for multiplexing/demultiplexing in a digital communication system using time division multiplex. The arrangement includes a switching arrangement with a first switching device for switching data and second switching devices for multiplexing and/or demultiplexing data. One or more second switching devices are connected to the first switching device over terminal connection links including a logical interface which includes a number of time slots arranged in rows and columns. The arrangement further includes a device for providing resources on the interface of the first terminal connection link. Resources for at least two different functionalities are reserved using reservation of resources based on columns in the interface and reservation based on time slots in the interface, respectively.