Abstract: For a ring protection method in a packet transport network a failure is detected at a first network node (N4) in the ring (1, 2). The failure is communicated along the ring (1, 2) using an automatic protection switching protocol. At the first node (N4) or at a second node (N1) adjacent to the failure, a protection switch-over for at least one protected traffic stream (4) is activated by redirecting the traffic stream (4) into the reverse direction of the ring (1, 2). Selected network nodes (N2, N5) along the ring squelch the traffic stream (4) in accordance with pre-configured squelching tables. Squelching is performed only by networks nodes along the ring which perform either an add function or a drop & continue function for the traffic stream (4) to be squelched.

Abstract: Efficient protection mechanisms for ring based label-switching networks are designed to protect point-to-point label switching paths (LSPs) while preventing misconnection and mismerge situations. The protection switching is performed by nodes adjacent to the point of failure. The switching decision is based on a locally detected signal fail condition. The operation of the protection mechanisms does not require the use of any protection switching protocol. In one embodiment of the present invention, the protection is achieved by assigning an exclusive label to each LSP. In another embodiment, the protection is achieved by providing a closed-loop protection tunnel and assigning a tunnel label for each such protection tunnel. In yet another embodiment, the protection is achieved by establishing a mirror path for each protected LSP.

Abstract: Efficient protection mechanisms for ring-based label-switching networks, such as multi-protocol label switching (MPLS) networks. The protection mechanisms are designed to protect point-to-multipoint label switching paths (LSPs). In steering ring protection embodiments, the nodes of the ring network are provided with pre-configured tables that enable each node to operate in both working mode and protection mode. The information required for each node to switch between the two modes in included in its respective table during the pre-configuration of the ring network. In wrapping ring protection embodiments, the wrapping is performed by assigning a unique LSP label to each LSP and further configuring each intermediate node in the ring network to transparently pass data packets including the unique LSP label. Upon detecting a failure in a network node, the data packets including the unique LSP label are switched to a protection ring.

Abstract: For a ring protection method in a packet transport network a failure is detected at a first network node (N4) in the ring (1, 2). The failure is communicated along the ring (1, 2) using an automatic protection switching protocol. At the first node (N4) or at a second node (N1) adjacent to the failure, a protection switch-over for at least one protected traffic stream (4) is activated by redirecting the traffic stream (4) into the reverse direction of the ring (1, 2). Selected network nodes (N2, N5) along the ring squelch the traffic stream (4) in accordance with pre-configured squelching tables. Squelching is performed only by networks nodes along the ring which perform either an add function or a drop&continue function for the traffic stream (4) to be squelched.