Name
summary-address — router, OSPF, IS-IS, BGP
Synopsis
BGP:
summary-addressaddress subnet-maskno summary-addressaddress subnet-mask
OSPF:
summary-addressaddress subnet-mask[not-advertise] [tagtag-value] no summary-addressaddress subnet-mask
IS-IS:
summary-addressaddress subnet-mask{level-1 | level-2 | level-1-2} no summary-addressaddress subnet-mask{level-1 | level-2 | level-1-2}
Configures
Route summarization
Default
Disabled
Description
This command allows you to create a single route that covers a set of smaller routes, thus reducing the number of routes in the routing table. Use the no form of the command to return to the default, where the router does not summarize routes.
-
address The destination address for the summarized route.
-
subnet-mask A subnet mask that indicates which addresses should be included in the summarized route.
-
level-1,level-2,level-1-2 IS-IS only. The router summarizes only routes that are being redistributed into the given level.
-
not-advertise Optional. OSPF only. Routes are not advertised when translating a type 7 link state announcement from OSPF.
-
tagtag-value Optional. OSPF only. Used as a match value for route maps.
Example
Assume that we know routes for 10.10.1.0, 10.10.2.0, 10.10.3.0, and so on. Instead of advertising separate routes, we can summarize by combining these routes into a single route for 10.10.0.0:
summary-address 10.10.0.0 255.255.0.0