An interface link layer device (1) to be connected in-between a first sub net-work (5) and a long delay link (3) to which at least one second sub network (4) is connected via another interface link layer device (2) is able to simulate or replace time critical messages of the at least one second sub network (4). To set-up a network with such interface link layer devices information about the configuration of the sub network (5; 4) connected to an interface link layer device (1; 2) is transmitted from said respective interface link layer device (1; 2) to all other interface link layer devices (2; 1) connected to said respective interface link layer device (1; 2) via the long delay link (3), whereafter a respective interface link layer device (2; 1) connected thereto which received information about the configuration of at least one other sub network (5; 4) is able to perform the necessary simulation.