Cisco Systems 78-11741-02 manual Configuring Ospf Area Parameters, Nonbroadcast media, IPC-228

Configuring OSPF

Configuring OSPF Area Parameters

These parameters need only be configured in those devices that are themselves eligible to become the designated router or backup designated router (in other words, routers with a nonzero router priority value).

To configure routers that interconnect to nonbroadcast networks, use the following command in router configuration mode:

Command	Purpose
Router(config-router)# neighbor ip-address	Configures a router interconnecting to nonbroadcast networks.
[priority number] [poll-interval seconds]

You can specify the following neighbor parameters, as required:

•Priority for a neighboring router

•Nonbroadcast poll interval

On point-to-multipoint, nonbroadcast networks, you now use the neighbor router configuration command to identify neighbors. Assigning a cost to a neighbor is optional.

Prior to Cisco IOS Release 12.0, some customers were using point-to-multipoint on nonbroadcast media (such as classic IP over ATM), so their routers could not dynamically discover their neighbors. This feature allows the neighbor router configuration command to be used on point-to-multipoint interfaces.

On any point-to-multipoint interface (broadcast or not), the Cisco IOS software assumed the cost to each neighbor was equal. The cost was configured with the ip ospf cost interface configuration command. In reality, the bandwidth to each neighbor is different, so the cost should differ. With this feature, you can configure a separate cost to each neighbor. This feature applies to point-to-multipoint interfaces only.

To treat the interface as point-to-multipoint when the media does not support broadcast, use the following commands beginning in interface configuration mode:

	Command	Purpose
Step 1
	Router(config-if)# ip ospf network	Configures an interface as point-to-multipoint for
	point-to-multipoint non-broadcast	nonbroadcast media.
Step 2
	Router(config-if)# exit	Enters global configuration mode.
Step 3
	Router(config)# router ospf process-id	Configures an OSPF routing process and enters router
		configuration mode.
Step 4
	Router(config-router)# neighbor ip-address[cost	Specifies a neighbor and assigns a cost to the
	number]	neighbor.

Repeat Step 4 for each neighbor if you want to specify a cost. Otherwise, neighbors will assume the cost of the interface, based on the ip ospf cost interface configuration command.

Configuring OSPF Area Parameters

Our OSPF software allows you to configure several area parameters. These area parameters, shown in the following task table, include authentication, defining stub areas, and assigning specific costs to the default summary route. Authentication allows password-based protection against unauthorized access to an area.

Cisco IOS IP Configuration Guide

IPC-228