OSPF Support for Multi-VRF on CE Routers

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.

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.

Information About OSPF Support for Multi-VRF on CE Routers

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.

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. vpdn- group name
  5. exit
  6. resource-pool profile vpdn name
  7. vpdn group name
  8. vpn vrf vrf-name | id vpn-id
  9. exit
  10. router ospf process-id [vrf vpn-name ]
  11. 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

vpdn- group name

Example:


Router(config)# vpdn-group mygroup

Creates a VPDN group.

Step 5

exit

Example:


Router(config-vpdn)# exit

Leaves the configuration mode and returns to global configuration mode.

Step 6

resource-pool profile vpdn name

Example:


Router(config)# resource-pool profile vpdn company1

Creates a virtual private dialup network (VPDN) profile and enters VPDN profile configuration mode.

Step 7

vpdn group name

Example:


Router(config-vpdn-profile)# vpdn group mygroup

Associates a virtual private dialup network (VPDN) group with a customer or VPDN profile.

Step 8

vpn vrf vrf-name | id vpn-id

Example:


Router(config-vpdn)# vpn vrf grc

Specifies that the source and destination IPv4 addresses of a given virtual private dialup network (VPDN) group belong to a specified Virtual Private Network (VPN) routing and forwarding (VRF) instance.

Step 9

exit

Example:


Router(config-vpdn)# exit

Leaves the configuration mode and returns to global configuration mode.

Step 10

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 11

capability vrf-lite

Example:


Router(config-router)# 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 process command indicates that the PE router is currently connected to the backbone. 


Router# show ip ospf 12
 Routing Process "ospf 12" with ID 172.16.1.1 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 Example 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-lite command is entered to suppress the PE checks. 


!
ip cef
ip vrf grc
 rd 1:1
interface Serial2/0/0
 ip vrf forwarding grc
 ip address 192.168.1.1 255.255.255.252
!
interface Serial3/0/0
 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 192.168.2.0
 no auto-summary
 end
Device# 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, Serial2/0/0
                      [110/138] via 192.168.1.9, 00:06:08, Serial3/0/0
O IA 192.168.242.0/24 [110/74] via 192.168.1.13, 00:06:08, Serial2/0/0
O IA 192.168.193.0/24 [110/148] via 192.168.1.13, 00:06:08, Serial2/0/0
                      [110/148] via 192.168.1.9, 00:06:08, Serial3/0/0
O IA 192.168.128.0/24 [110/74] via 192.168.1.9, 00:06:08, Serial3/0/0
O IA 192.168.129.0/24 [110/84] via 192.168.1.9, 00:06:08, Serial3/0/0
O IA 192.168.130.0/24 [110/84] via 192.168.1.9, 00:06:08, Serial3/0/0
     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, Serial2/0/0
O E2    172.16.10.0 [110/5] via 192.168.1.13, 00:06:08, Serial2/0/0
O IA 192.168.131.0/24 [110/94] via 192.168.1.9, 00:06:20, Serial3/0/0
     192.168.1.0/30 is subnetted, 4 subnets
C       192.168.1.8 is directly connected, Serial3/0/0
C       192.168.1.12 is directly connected, Serial2/0/0
O       192.168.1.0 [110/128] via 192.168.1.9, 00:06:20, Serial3/0/0
O       192.168.1.4 [110/128] via 192.168.1.13, 00:06:20, Serial2/0/0

Additional References

For additional information related to OSPF support for multi-VRF on CE routers, see the following references.

Related Documents

Related Topic

Document Title

Configuring OSPF

"Configuring OSPF"

Multiprotocol Label Switching (MPLS)

Cisco IOS XE Multiprotocol Label Switching Configuration Guide, Release 2

OSPF commands

Cisco IOS IP Routing: OSPF Command Reference

Cisco IOS master command list, all releases

Cisco IOS Master Command List, All Releases

Standards

Standard

Title

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

--

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

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

RFCs

RFC

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

Cisco IOS XE Release 2.1

Cisco IOS XE Release 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

Table 2. Feature Information for OSPF Support for Multi-VRF on CE Routers

Feature Name

Releases

Feature Information

OSPF Support for Multi-VRF on CE Routers

Cisco IOS XE Release 17.4

This feature was introduced.

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.