What is the different type of route summarization available in OSPF?

OSPF allows for two forms of summarization.
-One form of summarization is used when summarizing routes redistributed in to OSPF from another routing protocol.

-The other form of summarization is used when summarizing an area. With both forms of summarization, summary LSAs are created and flooded toward Location 0, or the central source area. The backbone location, in turn, floods the url states to the other areas.