A NEW PROTOCOL FOR ROUTE DISCOVERY IN MULTIPLE-RING NETWORKS .2. MULTICAST, RECOVERY AND HIGH-SPEED PROCESSING

A new MAC protocol for route discovery in multiple-ring network, calle d the FTRD-protocol, was introduced in Part I. The present paper shows how the FTRD-protocol can find a description of a tree that spans a g roup of destinations. By placing such a description in the header of i ts frame, a source station can efficiently multicast the frame to the destination group. This requires no change in the operation of the sou rce routing bridges. Another issue addressed in the paper is the recov ery of the FTRD-protocol from error and failure conditions. When a bri dge or the source suspects that the protocol is deadlocked. it initiat es an independent recovery protocol that clears the network and prepar es it for a new execution of the FTRD-protocol. The last issue address ed in the paper is the execution of the FTRD-protocol in a network wit h high-speed rings. The problem in such a network is that the bridges do not have sufficient time, after recognizing the route identity, to took in the local table and decide whether the relevant fields in the received frame need to be altered.