Abstract: For routing of frames through a system of bridge-connected network segments, a routing table is stored in each bridge, and each frame includes fields for a source segment identifier and a destination segment identifier. The routing tables reflect predetermined paths to each network segment as destination. For routing of a normal transmission frame, only the destination segment identifier included in the frame and a table look-up in each bridge are required. For deriving unknown routing information, a discovery frame is sent from source to destination terminal, initially including empty source and destination segment fields. Using the stored routing tables, bridges insert segment identifiers and forward discovery frames in such a way that only one arrives at the destination, carrying the correct source segment identifier and destination segment identifier which are then returned to the source terminal.

Abstract: Described are methods which preserve the order of the data frames within a data stream if the data stream is switched from one link to another. The first method achieves the order preservation by numbered switch frames that have to be exchanged between the nodes before the link switching is actually performed. In the second method, the switching is only prepared by exchanging special frames which indicate "clean" links. Actual switching takes place by just using an already prepared, i.e., "clean" link.

Abstract: Method and apparatus for supporting the Asynchronous Transfer Mode (ATM) connectionless service by means of Partial Connections (PCs) in an ATM system (18). These PCs are established between the source users (10, 11, 17) of said ATM system (18) and the destination switching nodes (14) to which the destination users (15) are linked. The use of PCs has no constraints on the size of the domain, because the information the source user (10, 11, 17) inserts in the Virtual Path Identifier/Virtual Channel Identifier (VPI/VCI) field of ATM cells to be transmitted to a destination user (15), is local to the source switching node (12) to which the source user (10, 11, 17) is connected. The information inserted in the VPI/VCI field identifies the PCs along which ATM cells are to be routed.