Example: Configuring a Single-Area OSPF Network

This example shows how to configure a single OSPF network.

Requirements
Overview
Configuration
Verification

Requirements

Before you begin:

Configure network interfaces. See the Junos OS Interfaces Configuration Guide for Security Devices.
Configure security filters. See the Junos OS Security Configuration Guide.
Configure the router identifiers for the devices in your OSPF network. See Example: Configuring an OSPF Router Identifier.

Overview

To activate OSPF on a network, you must enable the protocol on all interfaces within the network on which OSPF traffic is to travel. To enable OSPF, you must configure one or more interfaces on the device within an OSPF area. Once the interfaces are configured, OSPF LSAs are transmitted on all OSPF-enabled interfaces, and the network topology is shared throughout the network.

In an AS, the backbone area is always assigned area ID 0.0.0.0 Within a simple, single-area network, this is also the ID of the area. Area IDs are unique numeric identifiers, in dotted decimal notation. Area IDs need only be unique within an AS. All other networks or areas in the AS must be directly connected to the backbone area by area border routers that have interfaces in more than one area. In this example, you create the backbone area and add interfaces such as ge-0/0/0 as needed to the OSPF area.

To use OSPF on the device, you must configure at least one OSPF area, like the one shown in Figure 1.

Figure 17: Typical Single-Area OSPF Network Topology

Image g015028.gif

Configuration

Step-by-Step Procedure

To configure a single-area OSPF network:

Configure the single-area OSPF network.
[edit]user@host# set protocols ospf area 0.0.0.0 interface ge-0/0/0
If you are done configuring the device, commit the configuration.
[edit]user@host# commit

Verification

To verify the configuration is working properly, enter the show protocols ospf command.