Configuring Ospf Area Parameters - Cisco 7604 Configuration Manual

Configuring OSPF

Configuring OSPF Area Parameters

You can configure several area parameters. These area parameters (shown in the following task table)
include setting authentication, defining stub areas, and assigning specific costs to the default summary
route. Authentication provides password-based protection against unauthorized access to an area.
Stub areas are areas into which information on external routes is not sent. Instead, there is a default
external route generated by the ABR, into the stub area for destinations outside the autonomous system.
To take advantage of the OSPF stub area support, default routing must be used in the stub area. To further
reduce the number of LSAs sent into a stub area, you can configure the no-summary keyword of the
area stub command on the ABR to prevent it from sending summary link advertisement (LSA type 3)
into the stub area.
To specify area parameters for your network, perform the following steps:
If you have not already done so, enter the router configuration mode for the OSPF process you want to
Step 1
configure by entering the following command:
hostname(config)# router ospf process_id
Enter any of the following commands:
Step 2
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•
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The following example shows how to configure the OSPF area parameters:
hostname(config)# router ospf 2
hostname(config-router)# area 0 authentication
hostname(config-router)# area 0 authentication message-digest
hostname(config-router)# area 17 stub
Catalyst 6500 Series Switch and Cisco 7600 Series Router Firewall Services Module Configuration Guide using ASDM
8-14
Number of interfaces in this area is 1
Area has no authentication
SPF algorithm executed 2 times
Area ranges are
Number of LSA 5. Checksum Sum 0x 209a3
Number of opaque link LSA 0. Checksum Sum 0x
Number of DCbitless LSA 0
Number of indication LSA 0
Number of DoNotAge LSA 0
Flood list length 0
To enable authentication for an OSPF area, enter the following command:
hostname(config-router)# area area-id authentication
To enable MD5 authentication for an OSPF area, enter the following command:
hostname(config-router)# area area-id authentication message-digest
To define an area to be a stub area, enter the following command:
hostname(config-router)# area area-id stub [no-summary]
To assign a specific cost to the default summary route used for the stub area, enter the following
command:
hostname(config-router)# area area-id default-cost cost
The cost is an integer from 1 to 65535. The default is 1.
Chapter 8 Configuring IP Routing and DHCP Services
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