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    Example: Configuring OSPF Passive Traffic Engineering Mode

    OSPF Passive Traffic Engineering Mode

    Ordinarily, interior routing protocols such as OSPF are not run on links between autonomous systems. However, for inter-AS traffic engineering to function properly, information about the inter-AS link—in particular, the address on the remote interface—must be made available inside the autonomous system (AS). This information is not normally included either in the external BGP (EBGP) reachability messages or in the OSPF routing advertisements.

    To flood this link address information within the AS and make it available for traffic engineering calculations, you must configure OSPF passive mode for traffic engineering on each inter-AS interface. You must also supply the remote address for OSPF to distribute and include it in the traffic engineering database. OSPF traffic engineering mode allows MPLS label-switched paths (LSPs) to dynamically discover OSPF AS boundary routers and to allow routers to establish a traffic engineering LSP across multiple autonomous systems.

    Example: Configuring OSPF Passive Traffic Engineering Mode

    This example shows how to configure OSPF passive mode for traffic engineering on an inter-AS interface. The AS boundary router link between the EBGP peers must be a directly connected link and must be configured as a passive traffic engineering link.

    Requirements

    Before you begin:

    Overview

    You can configure OSPF passive mode for traffic engineering on an inter-AS interface. The address used for the remote node of the OSPF passive traffic engineering link must be the same as the address used for the EBGP link. In this example, you configure interface so-1/1/0 in area 0.0.0.1 as the inter-AS link to distribute traffic engineering information with OSPF within the AS and include the following settings:

    • passive—Advertises the direct interface addresses on an interface without actually running OSPF on that interface. A passive interface is one for which the address information is advertised as an internal route in OSPF, but on which the protocol does not run.
    • traffic-engineering—Configures an interface in OSPF passive traffic-engineering mode to enable dynamic discovery of OSPF AS boundary routers. By default, OSPF passive traffic-engineering mode is disabled.
    • remote-node-id—Specifies the IP address at the far end of the inter-AS link. In this example, the remote IP address is 192.168.207.2.

    Configuration

    To quickly configure OSPF passive mode for traffic engineering, copy the following command, remove any line breaks, and paste it into the CLI.

    [edit] set protocols ospf area 0.0.0.1 interface so-1/1/0 passive traffic-engineering remote-node-id 192.168.207.2

    Step-by-Step Procedure

    To configure OSPF passive traffic engineering mode:

    1. Create an OSPF area.

      Note: To specify OSPFv3, include the ospf3 statement at the [edit protocols] hierarchy level.

      [edit]user@host# set protocols ospf area 0.0.0.1
    2. Configure interface so-1/1/0 as a passive interface configured for traffic engineering, and specify the IP address at the far end of the inter-AS link.
      [edit protocols ospf area 0.0.0.1]user@host# set interface so-1/1/0 passive traffic-engineering remote-node-id 192.168.207.2
    3. If you are done configuring the device, commit the configuration.
      [edit protocols ospf]user@host# commit

    Results

    Confirm your configuration by entering the show protocols ospf command. If the output does not display the intended configuration, repeat the instructions in this example to correct the configuration.

    user@host# show protocols ospf
    area 0.0.0.1 {interface so-1/1/0.0 {passive {traffic-engineering {remote-node-id 192.168.207.2;}}}}

    To confirm your OSPFv3 configuration, enter the show protocols ospf3 command.

    Verification

    Confirm that the configuration is working properly.

    Verifying the Status of OSPF Interfaces

    Purpose

    Verify the status of OSPF interfaces. If the interface is passive, the Adj count field is 0 because no adjacencies have been formed. Next to this field, you might also see the word Passive.

    Action

    From operational mode, enter the show ospf interface detail command for OSPFv2, and enter the show ospf3 interface detail command for OSPFv3.

    Modified: 2016-12-06