OSPF Support for Multi-VRF on CE Routers

Last Updated: June 24, 2011

The OSPF Support for Multi-VRF on CE Routers feature provides the capability of suppressing provider edge (PE) checks that are needed to prevent loops when the PE is performing a mutual redistribution of packets between the OSPF and BGP protocols. When VPN routing and forward (VRF) is used on a router that is not a PE (that is, one that is not running BGP), the checks can be turned off to allow for correct population of the VRF routing table with routes to IP prefixes.

OSPF multi-VRF allows you to split the router into multiple virtual routers, where each router contains its own set of interfaces, routing table, and forwarding table.

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest feature information and caveats, see 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 document.

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.

Information About OSPF Support for Multi-VRF on CE Routers

The OSPF Support for Multi-VRF on CE Routers feature provides the capability of suppressing provider edge (PE) checks that are needed to prevent loops when the PE is performing a mutual redistribution of packets between the OSPF and BGP protocols. When VPN routing and forward (VRF) is used on a router that is not a PE (that is, one that is not running BGP), the checks can be turned off to allow for correct population of the VRF routing table with routes to IP prefixes.

OSPF multi-VRF allows you to split the router into multiple virtual routers, where each router contains its own set of interfaces, routing table, and forwarding table. OSPF multi-VRF gives you the ability to segment parts of your network and configure those segments to perform specific functions, yet still maintain correct routing information.

How to Configure OSPF Support for Multi-VRF on CE Routers

Configuring the Multi-VRF Capability for OSPF Routing

Before You Begin

CEF must be running on the network.


SUMMARY STEPS

1.    enable

2.    show ip ospf [process-id]

3.    configure terminal

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

5.    capability vrf-lite


DETAILED STEPS
  Command or Action Purpose
Step 1
enable


Example:

Router> enable

 

Enables higher privilege levels, such as privileged EXEC mode.

  • Enter your password if prompted.
 
Step 2
show ip ospf [process-id]


Example:

Router> show ip ospf 1

 

Displays the status of the router. If the display indicates that the router is connected to the VPN backbone, you can use the capability vrf-lite command to decouple the PE router from the VPN backbone.

 
Step 3
configure terminal


Example:

Router# configure terminal

 

Enters global configuration mode.

 
Step 4
router ospf process-id [vrf vpn-name]


Example:

Router(config)# router ospf 1 vrf grc

 

Enables OSPF routing and enters router configuration mode.

  • The process-id argument identifies the OSPF process.
  • Use the vrf keyword and vpn-name argument to identify a VPN.
 
Step 5
capability vrf-lite


Example:

Router(config)# capability vrf-lite

 

Applies the multi-VRF capability to the OSPF process.

 

Verifying the OSPF Multi-VRF Configuration

No specific debug or show commands are associated with this feature. You can verify the success of the OSPF multi-VRF configuration by using the show ip ospf[process-id] command to verify that the router is not connected to the VPN backbone.

This output from the show ip ospf processcommand indicates that the PE router is currently connected to the backbone. 

Router# show ip ospf 12
 Routing Process "ospf 12" with ID 151.1.1.1 and Domain ID 0.0.0.12
 Supports only single TOS(TOS0) routes
 Supports opaque LSA
 Connected to MPLS VPN Superbackbone
 SPF schedule delay 5 secs, Hold time between two SPFs 10 secs
 Minimum LSA interval 5 secs. Minimum LSA arrival 1 secs
 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 0. 0 normal 0 stub 0 nssa
 External flood list length 0

When the OSPF VRF process is configured with the capability vrf-lite command under the router ospf command, the "Connected to MPLS VPN Superbackbone" line will not be present in the display.

Configuration Examples for OSPF Support for Multi-VRF on CE Routers

Example Configuring the Multi-VRF Capability

This example shows a basic OSPF network with a VRF named grc configured. The capability vrf-litecommand is entered to suppress the PE checks.

!
ip cef
ip vrf grc
   rd 1:1
interface Serial2/0
  ip vrf forwarding grc
  ip address 192.168.1.1 255.255.255.252
!
interface Serial3/0
  ip vrf forwarding grc
  ip address 192.168.2.1 255.255.255.252
...
!
router ospf 9000 vrf grc
  log-adjacency-changes
  capability vrf-lite
  redistribute rip metric 1 subnets
  network 192.168.1.0 0.0.0.255 area 0
!
router rip
  address-family ipv4 vrf grc
  redistribute ospf 9000 vrf grc
  network network 192.168.2.0
  no auto-summary
  end
Router# show ip route vrf grc
Routing Table: grc
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area 
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route
Gateway of last resort is not set
O IA 192.168.192.0/24 [110/138] via 192.168.1.13, 00:06:08, Serial2/0
                      [110/138] via 192.168.1.9, 00:06:08, Serial3/0
O IA 192.168.242.0/24 [110/74] via 192.168.1.13, 00:06:08, Serial2/0
O IA 192.168.193.0/24 [110/148] via 192.168.1.13, 00:06:08, Serial2/0
                      [110/148] via 192.168.1.9, 00:06:08, Serial3/0
O IA 192.168.128.0/24 [110/74] via 192.168.1.9, 00:06:08, Serial3/0
O IA 192.168.129.0/24 [110/84] via 192.168.1.9, 00:06:08, Serial3/0
O IA 192.168.130.0/24 [110/84] via 192.168.1.9, 00:06:08, Serial3/0
     172.16.0.0/24 is subnetted, 2 subnets
O E2    172.16.9.0 [110/5] via 192.168.1.13, 00:06:08, Serial2/0
O E2    172.16.10.0 [110/5] via 192.168.1.13, 00:06:08, Serial2/0
O IA 192.168.131.0/24 [110/94] via 192.168.1.9, 00:06:20, Serial3/0
     192.168.1.0/30 is subnetted, 4 subnets
C       192.168.1.8 is directly connected, Serial3/0
C       192.168.1.12 is directly connected, Serial2/0
O       192.168.1.0 [110/128] via 192.168.1.9, 00:06:20, Serial3/0
O       192.168.1.4 [110/128] via 192.168.1.13, 00:06:20, Serial2/0

Example Verifying the OSPF Multi-VRF Configuration

This example illustrates the output display from the show ip ospf process command after OSPF multi-VRF has been configured on the router.

Router# show ip ospf database external 172.16.0.0 self
            OSPF Router with ID (10.0.0.1) (Process ID 100)
                 Type-5 AS External Link States
   LS age: 175
   Options: (No TOS-capability, DC)
   LS Type: AS External Link
   Link State ID: 172.16.0.0 (External Network Number )
   Advertising Router: 10.0.0.1
   LS Seq Number: 80000001
   Checksum: 0xEA9E
   Length: 36
   Network Mask: /8
         Metric Type: 2 (Larger than any link state path)
         MTID: 0
         Metric: 20
         Forward Address: 0.0.0.0
         External Route Tag: 0

Additional References

Related Documents

Related Topic

Document Title

Configuring OSPF

Configuring OSPF

Multiprotocol Label Switching (MPLS)

MPLS Multi-VRF (VRF Lite) Support

Standards

Standards

Title

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

--

MIBs

MIBs

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 software releases, and feature sets, use Cisco MIB Locator found at the following URL:

http://www.cisco.com/go/mibs

RFCs

RFCs

Title

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

--

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 Multi-VRF on CE Routers

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 Multi-VRF on CE Routers

Feature Name

Releases

Feature Information

OSPF Support for Multi-VRF on CE Routers

12.0(21)ST 12.0(22)S 12.2(8)B 12.2(13)T 12.2(14)S Cisco IOS XE 3.1.0 SG

The OSPF Support for Multi-VRF on CE Routers feature provides the capability to suppress provider edge (PE) checks that are needed to prevent loops when the PE is performing a mutual redistribution of packets between the OSPF and BGP protocols. When VPN routing and forwarding (VRF) is used on a router that is not a PE (that is, one that is not running BGP), the checks can be turned off to allow for correct population of the VRF routing table with routes to IP prefixes.

The following commands are introduced or modified in the feature documented in this module:

  • capability vrf-lite

Glossary

CE Router --Customer Edge router, an edge router in the C network, defined as a C router which attaches directly to a P router.

C Network --Customer (enterprise or service provider) network.

C Router --Customer router, a router in the C network.

LSA --link-state advertisement . Broadcast packet used by link-state protocols that contains information about neighbors and path costs. LSAs are used by the receiving routers to maintain their routing tables.

PE Router --Provider Edge router, an edge router in the P network, defined as a P router which attaches directly to a C router.

P Network --MPLS-capable service provider core network. P routers perform MPLS.

P Router --Provider router, a router in the P network.

SPF --shortest path first. A routing algorithm that iterates on length of path to determine a shortest-path spanning tree.

VPN --Virtual Private Network. Enables IP traffic to travel securely over a public TCP/IP network by encrypting all traffic from one network to another.

VRF --VPN Routing and Forwarding.

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Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.