This is the TE-specific routing metric (cost) assigned to this link, used by RSVP-TE/CSPF path computation to decide which links are preferred when computing explicit or constrained paths for MPLS tunnels -- lower cost generally means a more preferred link. This is distinct from a plain IGP metric because it's specifically consulted during constraint-based tunnel path selection, so changing it can redirect where new tunnels get signaled without touching regular IP routing. Setting this to an artificially high value like 65535 on an aging or congested link is a common technique to steer new tunnel placements away from it while leaving normal IP traffic routing untouched.