Abstract: In order to measure the latency of a particular transport service from end to end, a method of measuring the latency of a transport connection between a first network node (N1) and a second network node (N2) is provided, which makes use of a virtual concatenation function with a buffer (B) to compensate the differential delay between members in a received virtual concatenation group. In particular, the first network node (N1) creates a virtual concatenation group which has as members at least two multiplexing units (VC4—1, VC4—2). A first of the two (VC4—1) is used as a reference for the latency measurement. The second (VC4—2) is sent to the second network node (N2), where it is looped back to said first network node (N1). The first network node (N1), by using its buffer (B) available for re-aligning members of a virtual concatenation group, determines a latency difference between the first and second multiplexing units (VC4—1, VC4—2).

Abstract: The present invention relates to a method for restoring connections in a network, in particular in a telecommunication network, the network being provided with a data plane, a control plane and a number of nodes (1, 2, 3, 4, 5, 6, 7), comprising: detecting and localizing a fault (F) within the network, determining affected connections, selecting alternative paths (1-5-3-4, 1-2-7-4, 1-5-2-3-4, 1-2-5-3-4, 1-2-3-6-4) available to recover said failed connections, replacing nominal paths (1-2-3-4) of the affected connections with selected alternative paths (1-5-3-4, 1-2-7-4, 1-5-2-3-4, 1-2-5-3-4, 1-2-3-6-4) for realizing said connections.

Abstract: To restore a failed working path (WP) in a transport network, a restoration request is relayed between adjacent network elements (NE1, NE2) and the path set up hop by hop over spare resources by establishing local crossconnections (CC1, CC2) conforming to the request according to routing information locally stored within the network elements. During failure free operation, a low priority path (LPP A) for extra traffic with different signal structure is allowed on the spare resources and pre-empted in the case of a failure. The restoration request is forwarded using the old signal structure of the extra traffic path. Only after reception of a confirmation sent back by the peering node (NE2) using the new signal structure, the I/O port (211) is also reconfigured to the new signal structure.

Abstract: Transmission signals in a transport network are multiplexed from traffic streams respectively representing paths. Each path is identified with a path tag and forwarding information is provided in each network element. Failed paths in the network are restored in that the source network element crossconnects the affected traffic stream to an alternate output port and subsequent network elements receiving this unexpected traffic stream at an input port check the received path tag, determine an appropriate output port based on the tag and the forwarding information, and establish an internal cross-connection between the input port and corresponding output port.

Abstract: Failures are localized through the use of a Tandem Connection along a segment of a transmission path (P) to be monitored, non-intrusive intermediate Tandem Connection monitors (M), and temporary Tandem Connection sources created along the path segment in the case of a failure (F) in order to forward information about the fault location at least in downstream direction but preferably also in upstream direction. In particular, a failure adjacent network element (N3) detects the failure and activates a temporary tandem connection source function (TS3d, TS3u). This function creates a valid tandem connection signal and insert therein a failed link identifier (TTI). The network element (N4) terminating the tandem connection generates an alarm report including the failed link as indicated by the failed link identifier.

Abstract: Failures are localized through the use of a Tandem Connection along a segment of a transmission path (P) to be monitored, non-intrusive intermediate Tandem Connection monitors (M), and temporary Tandem Connection sources created along the path segment in the case of a failure (F) in order to forward information about the fault location at least in downstream direction but preferably also in upstream direction. In particular, a failure adjacent network element (N3) detects the failure and activates a temporary tandem connection source function (TS3d, TS3u). This function creates a valid tandem connection signal and insert therein a failed link identifier (TTI). The network element (N4) terminating the tandem connection generates an alarm report including the failed link as indicated by the failed link identifier.

Abstract: To restore a failed working path (WP) in a transport network, a restoration request is relayed between adjacent network elements (NE1, NE2) and the path set up hop by hop over spare resources by establishing local crossconnections (CC1, CC2) conforming to the request according to routing information locally stored within the network elements. During failure free operation, a low priority path (LPP A) for extra traffic with different signal structure is allowed on the spare resources and pre-empted in the case of a failure. The restoration request is forwarded using the old signal structure of the extra traffic path. Only after reception of a confirmation sent back by the peering node (NE2) using the new signal structure, the I/O port (211) is also reconfigured to the new signal structure.

Abstract: Transmission signals in a transport network are multiplexed from traffic streams respectively representing paths. Each path is identified with a path tag and forwarding information is provided in each network element. Failed paths in the network are restored in that the source network element crossconnects the affected traffic stream to an alternate output port and subsequent network elements receiving this unexpected traffic stream at an input port check the received path tag, determine an appropriate output port based on the tag and the forwarding information, and establish an internal cross-connection between the input port and corresponding output port.