By default, when changes occur to a type 5 or type
7 LSA, OSPF recalculates new, loop-free routes for only the LSAs that
change. When a subset of LSAs in the external link-state database
change, a full recalculation is not necessary. However, through the
CLI, you can disable incremental SPF so the router can perform a full
SPF on all external LSAs in the link-state database.
disable-incremental-external-spf
Use to disable incremental external SPF on the router.
When issued, this command results in a full SPF when
an event occurs to trigger an external SPF.
