Time aware path computation

A path computation method for use in a communications network having path resources usable for implementing paths, the method having steps of:

• receiving a request for computation of a new path in the network, the request indicating a future time interval when the path is desired,
• making a selection from a log of paths already reserved represented in terms of path resource reservations for each respective reserved path, at least some of the path resource reservations having an associated time interval, and the selection comprising at least those of the reserved paths whose associated time interval corresponds to the future time interval,
• sending the selected paths as reservation requests to a path computation element, to enable the path computation element to generate a future network status at the future time interval having at least a representation of availability of the path resources at the future time interval, and
• sending the request to the path computation element to enable the path computation element to compute which path resources to select for the new path according to the future network status.

Apparatus for path computation in a communications network having path resources usable for implementing paths, the apparatus having:

• an interface arranged to receive a request for computation of a new path in the network, the request indicating a future time interval when the new path is desired;
• and
• a processor configured to:
• select paths in a log which have path resource reservations at the future time interval;
• send path reservation requests for the selected paths;
• and
• generate a future network status at the future time interval based on the selected paths, having at least a representation of availability of respective ones of the path resources at the future time interval, the generating being based on a selection from a log of paths already reserved represented in terms of path resource reservations for each respective reserved path, at least some of the path resource reservations having an associated time interval, and the selection comprising at least those of the reserved paths whose associated time interval corresponds to the future time interval, and
• the processor being configured to compute which of the path resources to select for the new path according to the future network status.

Apparatus for path computation in a communications network having path resources for implementing paths, the apparatus having:

• an interface for receiving a request for computation of a new path in the network, the request indicating a future time interval when the path is desired;
• and
• a processor configured to:
• make a selection from a log of paths already reserved represented in terms of path resource reservations for each respective reserved path, at least some of the path resource reservations having an associated time interval, and the selection comprising at least those of the reserved paths whose associated time interval corresponds to the future time interval, and
• to send the selected paths as reservation requests to a path computation element, to enable the path computation element to generate a future network status at the future time interval, and
• the processor being configured to send the request to the path computation element to enable it to compute which path resources to select for the new path.