| 摘要 |
<p>A method of ring protection is provided. The method includes feeding traffic on two transmission rings at a head end node and summing all traffic received on the transmission rings at the head end node. When a facility failure is detected, by a remote node, on one of the two transmission rings, transmitting forward alarm signals on the one transmission ring and return alarm signals on the other transmission ring and globally selecting the one transmission ring to transmit traffic and the other transmission ring to receive traffic from the head end node. When a remote node receives a forward alarm signal, the remote node passes the forward alarm signal on the transmission ring on which the forward alarm signal was received and globally selects the transmission ring on which the forward alarm signal was received to transmit traffic and the other transmission ring to receive traffic from the head end node. In one embodiment, the protection scheme is applied to ATM on SDH/SONET ring topologies where traffic flow is to/from a head end node from/to remote nodes. In one embodiment, the protection scheme is applied to an access network, a metropolitan network or the like. In one embodiment, the access network is an asynchronous digital subscriber line (ADSL) access network, an xDSL access network or other broadband access network. For example, the head end node may be is any one one of a number of access network equipment elements such as, an ADSL transmission unit-central office, a central office DSLAM, an integrated DLC, a remote DSLAM that is subtended from a DSLAM or an ATM switch, a remote access multiplexer subtented from a DSLAM or an ATM switch, or the like.</p> |
