Multiarea OSPF is used to divide a large OSPF network. Too many routers in one area increase the load on the CPU and create a large link-state database. In this chapter, directions are provided to effectively partition a large single area into multiple areas. Area 0 used in a single-area OSPF is known as the backbone area.

Discussion is focused on the LSAs exchanged between areas. In addition, activities for configuring OSPFv2 and OSPFv3 are provided. The chapter concludes with the show commands used to verify OSPF configurations.