OSPF Summarization

In OSPF, summarization can be configured on two types of routers: ABR/s and/or ASBRs. The internal OSPF routes can only be summarized on ABRs whereas the external (redistributed) routes can only be summarized on ASBRs. When summarizing internal routes on ABRs the “area xx range” command must be used, where xx is the area id. Summarization on ASBR can be accomplished by using the “summary address” command.