Constrained Shortest Path First For Temporal Tunnel Services

A method implemented in a network element (NE), comprising:

• receiving, via a receiver, a request requesting creation of a temporal label switched path (LSP) in a network, wherein the request indicates an ingress, an egress, a network constraint, a scheduled time interval having an elastic range, a predetermined start time and a predetermined end time for the temporal LSP to carry first traffic in a shifted time interval within the elastic range of the scheduled time interval;
• computing, via a processor, a shortest path for the temporal LSP by determining a minimum amount of time to shift the scheduled time interval from the start time such that the path satisfies the network constraint in a shifted time interval and the shifted time interval is positioned within the elastic time range and with the minimum time shift;
• determining, via the processor, whether a next hop link from the NE to a next downstream node on the shortest path comprises a sufficient amount of network resources in the shifted time interval to satisfy the network constraint;
• and
• reserving, via the processor, the network resource on the next hop link for use during the shifted time interval for the temporal LSP in advance of the predetermined start time according to the network constraint to facilitate data forwarding for the temporal LSP in the shifted time interval when the next hop link from the NE to the next downstream node on the shortest path comprises the sufficient amount of network resources in the shifted time interval to satisfy the network constraint.

An apparatus, comprising:

• a receiver configured to receive a request requesting creation of a temporal label switched path (LSP) in a network, wherein the request indicates an ingress, an egress, a network constraint and a scheduled time interval having an elastic range, a predetermined start time and a predetermined end time for the temporal LSP to carry traffic in a shifted time interval within the elastic range of the scheduled time interval;
• a processor coupled to the receiver and configured to:
• compute a shortest path for the temporal LSP by determining a minimum amount of time to shift the scheduled time interval from the start time such that the path satisfies the network constraint in a shifted time interval and the shifted time interval is positioned within the elastic time range and with the minimum time shift;
• determine whether a next hop link from the apparatus to a next downstream node on the shortest path comprises a sufficient amount of network resources in the shifted time interval to satisfy the network constraint;
• and
• reserve the network resource on the next hop link for use during the shifted time interval for the temporal LSP in advance of a predetermined start time according to the network constraint to facilitate data forwarding for the temporal LSP in the shifted time interval.