How CSPF Selects a Path

To select a path, CSPF follows these steps:

Computes LSPs one at a time, beginning with the highest priority LSP (the one with the lowest setup priority value). Among LSPs of equal priority, CSPF starts with those that have the highest bandwidth requirement.
Prunes the TED of all the links that are not full duplex and do not have sufficient reservable bandwidth.
If the LSP configuration includes the include statement, prunes all links that do not share any included colors.
If the LSP configuration includes the exclude statement, prunes all links that contain excluded colors. If the link does not have a color, it is accepted.
Finds the shortest path toward the LSP’s egress router, taking into account explicit-path constraints. For example, if the path must pass through Router A, two separate SPFs are computed, one from the ingress router to Router A, the other from Router A to the egress router.
If several paths have equal cost, chooses the one whose last-hop address is the same as the LSP’s destination.
If several equal-cost paths remain, selects the one with the fewest number of hops.
If several equal-cost paths remain, applies the CSPF load-balancing rule configured on the LSP (least fill, most fill, or random).