Establishing internal control paths in atm node

Abstract

To form internal control paths in an ATM node ( ), “half trails” (HF) are initially established and subsequently connected to form complete trails (FT). In an ATM node having plural node entities ( ) or device boards connected to a switch core ( ), for each node entity a main control path program ( ) executed by a node main processor () initially forms both a listening half trail and a sending half trail extending from the node main processor and switch core. Separately and independently, i.e., without prior communication with the node main processor, an entity control path program ( ) executed by an entity processor ( ) at each node entity establishes a listening half trail between itself and the switch core. For each node entity, the entity control path program establishes the same VPI/VCI as the listening half trail. The entity processor then receives on its independently established listening half trail (i.e., on the predetermined VPI/VCI) a handshaking request. The handshaking request (HR) includes information indicating what half trail (e.g., what other VPI/VCI) the node entity can use as a sending half trail for sending control cells to node main processor. The node entity then responds to the handshaking request with a response message (RM) sent over the sending half trail. Single stage and multi-stage ATM node embodiments are provided. The entity control path program ( ) is preferably the same for each node entity.