IP Routing: OSPF Configuration Guide, Cisco IOS XE Release 3S (Cisco ASR 1000)
OSPF Support for Unlimited Software VRFs per PE Router
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OSPF Support for Unlimited Software VRFs per PE Router

OSPF Support for Unlimited Software VRFs per PE Router

In a Multiprotocol Label Switching--Virtual Private Network (MPLS-VPN) deployment, each VPN routing and forwarding instance (VRF) needs a separate Open Shortest Path First (OSPF) process when configured to run OSPF. The OSPF Support for Unlimited Software VRFs per Provider Edge (PE) Router feature addresses the scalability issue for OSPF VPNs by eliminating the OSPF VPN limit of 32 processes.

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table at the end of this module.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/​go/​cfn. An account on Cisco.com is not required.

Prerequisites for OSPF Support for Unlimited Software VRFs per PE Router

You must have OSPF configured in your network.

Restrictions for OSPF Support for Unlimited Software VRFs per PE Router

Only 32 processes per VRF can be supported. For different VRF processes, there is no limit.

Information About OSPF Support for Unlimited Software VRFs per PE Router

Before Cisco IOS Releases 12.3(4)T and 12.0(27)S, a separate OSPF process was necessary for each VRF that receives VPN routes via OSPF. When VPNs are deployed, an MPLS Provider Edge (PE) router will be running both multiprotocol Border Gateway Protocol (BGP) for VPN distribution, and Interior Gateway Protocol (IGP) for PE-P connectivity. OSPF is commonly used as the IGP between a customer edge (CE) router and a PE router. OSPF was not scalable in a VPN deployment because of the limit of 32 processes. By default, one process is used for connected routes and another process is used for static routes; therefore only 28 processes can be created for VRFs.

The OSPF Support for Unlimited Software VRFs per Provider Edge Router feature allows for an approximate range of 300 to 10,000 VRFs, depending on the particular platform and on the applications, processes, and protocols that are currently running on the platform.

How to Configure OSPF Support for Unlimited Software VRFs per PE Router

Configuring Unlimited Software VRFs per PE Router

SUMMARY STEPS

    1.    enable

    2.    configure terminal

    3.    ip vrf vpn-name

    4.    exit

    5.    router ospf process-id [vrf vpn-name]

    6.    end

    7.    show ip ospf [process-id]


DETAILED STEPS
     Command or ActionPurpose
    Step 1 enable


    Example:
    Router> enable
     

    Enables privileged EXEC mode.

    • Enter your password if prompted.
     
    Step 2 configure terminal


    Example:
    Router# configure terminal
     

    Enters global configuration mode.

     
    Step 3 ip vrf vpn-name


    Example:
    Router(config)# ip vrf crf-1
     

    Defines a VPN routing and forwarding (VRF) instance and enters VRP configuration mode.

     
    Step 4 exit


    Example:
    Router(config-vrf)# exit
     

    Returns to global configuration mode.

     
    Step 5 router ospf process-id [vrf vpn-name]


    Example:
    Router(config)# router ospf 1 vrf crf-1
     

    Enables OSPF routing.

    • The process-id argument identifies the OSPF process.
    • Use the vrf keyword and vpn-name argument to identify the VPN already defined in Step 3.
    Note   

    You can now configure as many OSPF VRF processes as needed. Repeat Steps 3-5 as needed.

     
    Step 6 end


    Example:
    Router(config-router)# end
     

    Returns to privileged EXEC mode.

     
    Step 7 show ip ospf [process-id]


    Example:
    Router# show ip ospf 1
     

    Displays general information about OSPF routing processes.

     

    Configuration Examples for OSPF Support for Unlimited Software VRFs per PE Router

    Example Configuring OSPF Support for Unlimited Software VRFs per PE Router

    This example shows a basic OSPF configuration using the router ospf command to configure OSPF VRF processes for the VRFs first, second, and third:

    Router> enable
    Router# configure terminal
    Router(config)# ip vrf first
    Router(config-vrf)# exit
    Router(config)# ip vrf second
    Router(config-vrf)# exit
    Router(config)# ip vrf third
    Router(config-vrf)# exit
    Router(config)# router ospf 12 vrf first
    Router(config-router)# exit
    Router(config)# router ospf 13 vrf second
    Router(config-router)# exit
    Router(config)# router ospf 14 vrf third
    Router(config)# end
    

    Example Verifying OSPF Support for Unlimited Software VRFs per PE Router

    This example illustrates the output from the show ip ospf command to verify that OSPF VRF process 12 has been created for the VRF named first. The output that relates to the VRF first appears in bold.

    Router# show ip ospf 12
    main ID type 0x0005, value 0.0.0.100
     Supports only single TOS(TOS0) routes
     Supports opaque LSA
     Supports Link-local Signaling (LLS)
     Supports area transit capability
     Connected to MPLS VPN Superbackbone, VRF first
     It is an area border router
     Initial SPF schedule delay 5000 msecs
     Minimum hold time between two consecutive SPFs 10000 msecs
     Maximum wait time between two consecutive SPFs 10000 msecs
     Incremental-SPF disabled
     Minimum LSA interval 5 secs
     Minimum LSA arrival 1000 msecs
     LSA group pacing timer 240 secs
     Interface flood pacing timer 33 msecs
     Retransmission pacing timer 66 msecs
     Number of external LSA 0. Checksum Sum 0x0
     Number of opaque AS LSA 0. Checksum Sum 0x0
     Number of DCbitless external and opaque AS LSA 0
     Number of DoNotAge external and opaque AS LSA 0
     Number of areas in this router is 1. 1 normal 0 stub 0 nssa
     Number of areas transit capable is 0
     External flood list length 0
        Area BACKBONE(0)
            Number of interfaces in this area is 1
            Area has no authentication
            SPF algorithm last executed 00:00:15.204 ago
            SPF algorithm executed 2 times
            Area ranges are
            Number of LSA 1. Checksum Sum 0xD9F3
            Number of opaque link LSA 0. Checksum Sum 0x0
            Number of DCbitless LSA 0
            Number of indication LSA 0
            Number of DoNotAge LSA 0
            Flood list length 0

    Additional References

    The following sections provide references related to the OSPF Support for Unlimited Software VRFs per Provider Edge Router feature.

    Related Documents

    Related Topic

    Document Title

    Configuring OSPF

    "Configuring OSPF"

    Standards

    Standard

    Title

    None

    --

    MIBs

    MIB

    MIBs Link

    No new or modified MIBs are supported by this feature, and support for existing MIBs has not been modified by this feature.

    To locate and download MIBs for selected platforms, Cisco IOS XE releases, and feature sets, use Cisco MIB Locator found at the following URL:

    http:/​/​www.cisco.com/​go/​mibs

    RFCs

    RFC

    Title

    None

    --

    Technical Assistance

    Description

    Link

    The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

    http:/​/​www.cisco.com/​cisco/​web/​support/​index.html

    Feature Information for OSPF Support for Unlimited Software VRFs per PE Router

    The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

    Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/​go/​cfn. An account on Cisco.com is not required.

    Table 1 Feature Information for OSPF Support for Unlimited Software VRFs per Provider Edge Router

    Feature Name

    Releases

    Feature Information

    OSPF Support for Unlimited Software VRFs per Provider Edge Router

    Cisco IOS XE Release 2.1

    In a Multiprotocol Label Switching--Virtual Private Network (MPLS-VPN) deployment, each VPN routing and forwarding instance (VRF) needs a separate Open Shortest Path First (OSPF) process when configured to run OSPF. The OSPF Support for Unlimited Software VRFs per Provider Edge Router feature addresses the scalability issue for OSPF VPNs by eliminating the OSPF VPN limit of 32 processes.