Selection of backup LFA for OSPF routing protocol

The default loop-free alternative (LFA) selection algorithm or criteria can be overridden with an LFA policy. These policies are configured per destination per primary next-hop interface or per destination. These backup policies enforce LFA selection based on admin-group, srlg, node, bandwidth, protection-type, and metric attributes of the backup path. During backup shortest-path-first (SPF) computation, each attribute (both node and link) of the backup path, stored per backup next hop, is accumulated by IGP. For the routes created internally by IGP, the attribute set of every backup path is evaluated against the policy configured per destination per prefix primary next-hop interface. The first or the best backup path is selected and installed as the backup next hop in the routing table.