Patent ID: 8867333

Claim:
A method for determining a restoration path corresponding to a primary path for a new service in a mesh network having a plurality of nodes interconnected by a plurality of links, the method comprising: (A) for each of a plurality of candidate restoration paths associated with the primary path: (1) for each link in the candidate restoration path: (i) assigning a link cost to the link; (ii) determining whether the primary path requires any additional restoration bandwidth to be reserved on the link based on whether the primary path is SRLG-disjoint from each other primary path that is currently protected by that link, wherein: a shared risk link group (SRLG) is a set of two or more links, for which a failure of any one link in the SRLG is associated with a relatively high risk of failure of the other links in the SRLG; and two paths are SRLG-disjoint when no two links in the two paths are members of any one SRLG; (iii) determining that sharing is possible for the link when it is determined that no additional restoration bandwidth is required to be reserved on the link; (iv) reducing the link cost by a factor R for each link of each candidate restoration path for which sharing is possible, wherein the factor R is a function of a sharing degree for each link; and (v) when sharing is not possible, then: (a) determining whether utilization of the link is greater than a specified threshold; (b) when the link utilization is greater than the specified threshold, then assigning the link cost as a function of an administrative weight for the link and available capacity on the link; and (c) when the link utilization is less than the specified threshold, then assigning the link cost as a function of the administrative weight for the link; and (2) generating a path cost for the candidate restoration path based on a sum of the link costs for the links of that candidate restoration path; and (B) selecting one of the candidate restoration paths for the primary path based on minimum path cost.