Example: Configuring an OSPF Interface on a Nonbroadcast Multiaccess Network

This example shows how to configure an OSPFv2 interface on a nonbroadcast multiaccess (NBMA) network on high-end SRX Series devices.

Requirements

Before you begin:

Overview

When you configure OSPFv2 on an NBMA network, you can use nonbroadcast mode to interoperate with other equipment. Because there is no autodiscovery mechanism, you must configure each neighbor.

Nonbroadcast mode treats the NBMA network as a partially connected LAN, electing designated and backup designated routers. All routing devices must have a direct connection to both the designated and backup designated routers; otherwise, unpredictable results can occur.

When you configure the interface, specify either the IP address or the interface name. Using both the IP address and the interface name produces an invalid configuration. For nonbroadcast interfaces, specify the IP address of the nonbroadcast interface as the interface name.

In this example, you configure the Ethernet interface xe-2/0/0.0 as an OSPFv2 interface in OSPF area 0.0.0.1 and specify the following settings:

Configuration

CLI Quick Configuration

To quickly configure this example, copy the following commands, paste them into a text file, remove any line breaks, change any details necessary to match your network configuration, copy and paste the commands into the CLI at the [edit] hierarchy level, and then enter commit from configuration mode.

[edit] set interfaces xe-2/0/0 unit 0 family inet address 192.0.2.1/24set protocols ospf area 0.0.0.1 interface xe-2/0/0.0 interface-type nbmaset protocols ospf area 0.0.0.1 interface xe-2/0/0.0 neighbor 192.0.2.2 eligibleset protocols ospf area 0.0.0.1 interface xe-2/0/0.0 hello-interval 130

Step-by-Step Procedure

The following example requires you to navigate various levels in the configuration hierarchy. For instructions on how to do that, see Using the CLI Editor in Configuration Mode.

To configure an OSPFv2 interface on an NBMA network:

  1. Configure the interface.
    [edit]user@host# set interfaces xe-2/0/0 unit 0 family inet address 192.0.2.1/24
  2. Create an OSPF area.
    [edit]user@host# edit protocols ospf area 0.0.0.1
  3. Assign the interface to the area.
    In this example, include the eligible keyword to allow the neighbor to be a designated router.
    [edit protocols ospf area 0.0.0.1 ]user@host# set interface xe-2/0/0.0 interface-type nbma neighbor 192.0.2.2 eligible
  4. Configure the hello interval.
    [edit protocols ospf area 0.0.0.1 ]user@host# set interface xe-2/0/0.0 hello-interval 130

Results

From configuration mode, confirm your configuration by entering the show interfaces and the show protocols ospf commands. If the output does not display the intended configuration, repeat the configuration instructions in this example to correct it.

user@host# show interfaces
xe-2/0/0 {unit 0 {family inet {address 192.0.2.1/24;}}}
user@host# show protocols ospf
area 0.0.0.1 {interface xe-2/0/0.0 {interface-type nbma;neighbor 192.0.2.2 eligible;hello-interval 130;}}

If you are done configuring the device, enter commit from configuration mode.

Verification

Confirm that the configuration is working properly.

Verifying the OSPF Interface

Purpose

Verify the interface configuration by confirming that the Type field displays NBMA.

Action

From operational mode, enter the show ospf interface detail command.

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