Cisco ASA 5505 Configuration Manual page 391

Chapter 21 Configuring OSPF
Click OK.
Step 12
Configuring Route Summarization When Redistributing Routes into OSPF
When routes from other protocols are redistributed into OSPF, each route is advertised individually in
an external LSA. However, you can configure the adaptive security appliance to advertise a single route
for all the redistributed routes that are covered by a specified network address and mask. This
configuration decreases the size of the OSPF link-state database.
Routes that match the specified IP Address mask pair can be suppressed. The Tag value can be used as
a match value for controlling redistribution through route maps.
There are two areas that you can configure for route summarization:
•
•
Add a Route Summary Address
The Summary Address pane displays information about the summary addresses configured for each
OSPF routing process.
Routes learned from other routing protocols can be summarized. The metric used to advertise the
summary is the smallest metric of all the more specific routes. Summary routes help reduce the size of
the routing table.
Using summary routes for OSPF causes an OSPF ASBR to advertise one external route as an aggregate
for all redistributed routes that are covered by the address. Only routes from other routing protocols that
are being redistributed into OSPF can be summarized.
Note
To configure the software advertisement on one summary route for all redistributed routes covered by a
network address and mask, perform the following steps:
In the main ASDM home page, choose Configuration > Device Setup > Routing > OSPF > Summary
Step 1
Address.
Choose Add.
Step 2
The Add OSPF Summary Address Entry dialog box appears. This allows you to add new entries to
existing entries in the Summary Address table. Some of the summary address information cannot be
changed when editing an existing entry.
Choose the specified OSPF Process ID associated with the summary address from the OSPF Process
Step 3
drop-down list. You cannot change this information when editing an existing entry.
Step 4 Enter the IP address of the summary address in the IP Address field. You cannot change this information
when editing an existing entry.
Step 5 Choose the network mask for the summary address from the Netmask drop-down list. You cannot change
this information when editing an existing entry.
OL-20339-01
Add a Route Summary Address
Add/Edit OSPF Summary Address
OSPF does not support summary-address 0.0.0.0 0.0.0.0.
Cisco ASA 5500 Series Configuration Guide using ASDM
Customizing OSPF
21-7