Graceful restart in OSPF makes uses of OSPF Type-9 LSAs – Link Local Opaque type 3. Quote from Appendix A of RFC 3623 Graceful OSPF Restart: A. Grace-LSA Format The grace-LSA is a link-local scoped Opaque-LSA [2], having an Opaque Type of 3 and an Opaque ID equal to 0. Grace-LSAs are originated by a […]