Configure OSPF Summary Addresses

When routes from other protocols are redistributed into OSPF, each route is advertised individually in an external LSA. However, you can configure the threat defense device to advertise a single route for all the redistributed routes that are included for 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.

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.

Procedure

Step 1

Choose Devices > Device Management, and edit the threat defense device.

Step 2

Click Routing.

Step 3

(For a virtual-router-aware device) From the virtual routers drop-down list, choose the virtual router for which you are configuring OSPF.

Step 4

Click OSPF.

Step 5

Select Summary Address > Add.

You can click Edit (edit icon) to edit, or use the right-click menu to cut, copy, past, insert, and delete summary addresses.

Step 6

Configure the following summary address options for each OSPF process:

  • OSPF Process— For a device using virtual routing, the drop-down lists the unique process IDs generated for the selected virtual router.

  • Available Network—The IP address of the summary address. Select one from the Available networks list and click Add, or to add a new network, click Add (add icon). See Network for the procedure for adding networks.

  • Tag—A 32-bit decimal value that is attached to each external route. This value is not used by OSPF itself, but may be used to communicate information between ASBRs.

  • Advertise—Advertises the summary route. Uncheck this check box to suppress routes that fall under the summary address. By default, this check box is checked.

Step 7

Click OK to save the summary address configuration.

Step 8

Click Save on the Routing page to save your changes.

What to do next

Continue with Configure OSPF Interfaces and Neighbors.