| 摘要 |
<p>A communications system comprises a plurality or network of switching nodes (10,12,14,16,18,20,22) interconnected by transmission links, time division multiplexed signals (2ii,28) being transported between entry nodes (10) and egress nodes (22) as "transactions" comprising a header portion (F1-F2) and a message portion (F3-F4), which may comprise signalling. The header portion (F1-F2) comprises a sequence of node exist address (NEA) which occur in the order in which the nodes will be encountered as the signal traverses the network. In each node (10-20), the leading node exit address (NEA) determines the exit through which the signal will emerge from that node so as to reach the next node in the sequence. The entire sequence of node exit addresses (NEA) is generated by access apparatus (26) at the entry node (10), conveniently by accessing a routing database (46) by means of a unique address (DIA) of a destination interface (26A) connected to an exit of the egress node (22) to which an intended recipient is connected. The destination interface address (DIA) may conveniently be produced by accessing another look-up table (36) using the recipient's directory number (DIR.NUM).</p> |
