Chapter 16. Summarizing External Routes
summary-address ip-address mask
summary-address ip-address mask not-advertise
ip-address—. IP address of the summary route.
mask—. Subnet mask used to generate the summary.
Purpose: OSPF can summarize routes that have been redistributed into OSPF. The summary can be applied to routes redistributed from a dynamic routing protocol, static routes, and connected routes. The router performing the redistribution is called an Autonomous System Boundary Router (ASBR). The summary-address command can be used on an ASBR or an Area Border Router (ABR). When used on an ABR, only external OSPF routes can be summarized. Using the not-advertise keyword suppresses the advertisement of the summary route by ...