Constrained disjoint path computation

An apparatus for determining multiple disjoint constrained paths in a communications network, comprising a processor, and a non-transitory computer readable medium storing instructions that are executable by the processor, wherein the processor is configured to perform:

• selecting upper bound constraints of delay metrics for each path in a disjoint path combination comprising two or more disjoint paths between a source node and a destination node;
• determining a minimum-cost disjoint path combination, and a minimum-delay disjoint path combination;
• computing a maximum delay constraint by summing the delay metrics of each path in the minimum-cost disjoint path combination, and computing a minimum delay constraint by summing the delay metrics of each path in the minimum-delay disjoint path combination;
• determining a candidate space including minimum-cost disjoint path combinations having a sum of delay metrics for paths in the disjoint path combination that fall within an interval between the maximum delay constraint and the minimum delay constraint;
• and
• selecting, from the candidate space, disjoint path combinations, wherein the delay metric of each path in the disjoint path combination is within the upper bound constraints.

A non-transitory computer-readable storage medium having stored therein instructions for determining multiple disjoint constrained paths in a communications network, wherein the instructions, when executed by a processor, cause the processor to:

• select upper bound constraints of delay metrics for each path in a disjoint path combination comprising two or more disjoint paths between a source node and a destination node;
• determine a minimum-cost disjoint path combination and a minimum-delay disjoint path combination;
• compute a maximum delay constraint by summing the delay metrics of each path in the minimum-cost disjoint path combination, and compute a minimum delay constraint by summing the delay metrics of each path in the minimum-delay disjoint path combination;
• determine a candidate space including disjoint path combinations having a sum of delay metrics for paths in the disjoint path combination that fall within an interval between the maximum delay constraint and the minimum delay constraint;
• and
• select, from the candidate space, disjoint path combinations wherein the delay metric of each path in the disjoint path combination is within the upper bound constraints.