| 摘要 |
<p>A protection system for an ATM network (30) having a primary node (11,21) and a secondary node (12,13,14, 22) interconnected through an ATM transport capable network (30) of any topology. For each ATM (VPC/VCC) connection between the primary (11,21) and the secondary node (12, 13,14,22) this interconnecting network (30) makes available two independent paths (16, 17) that form independent working and protection paths. The primary node (11,21) sends traffic cells over both working path (16 or 17) and protection path (17 or 16) and receives and merges the traffic cells from both the paths (16 and 17). The secondary node (12, 22) transmits and receives traffic cells either on the bi-directional working path (16 or 17) or on the bi-directional protection paths (17 or 16) and the continuity of the working and protection path is monitored through the creation of appropriate ATM test circuits, named Test Trails (19, 20), between the primary node (11,21) and the secondary node (12,13,14,22). If the secondary node (12,13,14,22) detects discontinuity of the Test Trail (19 or 20) for the path (16 or 17) in use to carry the local traffic cells, then the local traffic cells (15) at the secondary node (12, 13,14,22) are switched onto the appropriate protection path (17 or 16) while no switching function is performed on the primary node (11). The generation of ATM-AIS (forward alarm signal) is inhibited in the primary node (11,21) and in the interconnecting network (30), whereas the generation of ATM-RDI (return alarm signal) is inhibited in the secondary node (12,13,14,22).</p> |
