Table Of Contents

MPLS VPN: VRF Selection Using Policy-Based Routing

Finding Feature Information

Contents

Prerequisites for VRF Selection Using Policy-Based Routing

Restrictions for VRF Selection Using Policy-Based Routing

Information About VRF Selection Using Policy-Based Routing

Introduction to VRF Selection Using Policy-Based Routing

Policy-Based Routing Set Clauses: Overview

How to Configure VRF Selection Using Policy-Based Routing

Defining the Match Criteria for PBR VRF Selection

Match Criteria Defined Based on Packet Length

Prerequisites

Configuring PBR VRF Selection with a Standard Access List

Configuring PBR VRF Selection with a Named Access List

Configuring PBR VRF Selection in a Route Map

Prerequisites

Restrictions

Configuring PBR on the Interface

Restrictions

Configuring IP VRF Receive on the Interface

Verifying the Configuration of the VRF Selection Using Policy-Based Routing

Configuration Examples for VRF Selection Using Policy-Based Routing

Defining PBR VRF Selection in Access List: Example

Verifying VRF Selection Using Policy-Based Routing: Example

Additional References

Related Documents

Standards

MIBs

RFCs

Technical Assistance

Command Reference

Feature Information for VRF Selection Using Policy-Based Routing

Glossary

MPLS VPN: VRF Selection Using Policy-Based Routing

---

First Published: March 1, 2004

Last Updated: November 14, 2008

The MPLS VPN: VRF Selection Using Policy-Based Routing feature is an extension of the MPLS VPN: VRF Selection Based on Source IP Address feature. This feature introduces a policy-based routing (PBR) mechanism to classify and forward Virtual Private Network (VPN) traffic based on multiple VPN routing and forwarding (VRF) selection match criteria.

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 for VRF Selection Using Policy-Based Routing" section.

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

Contents

•Prerequisites for VRF Selection Using Policy-Based Routing

•Restrictions for VRF Selection Using Policy-Based Routing

•Information About VRF Selection Using Policy-Based Routing

•How to Configure VRF Selection Using Policy-Based Routing

•Configuration Examples for VRF Selection Using Policy-Based Routing

•Additional References

•Command Reference

•Feature Information for VRF Selection Using Policy-Based Routing

•Glossary

Prerequisites for VRF Selection Using Policy-Based Routing

The router must support PBR to configure this feature. For platforms that do not support PBR, use the VRF Selection Based on Source IP Address feature introduced in Cisco IOS Release 12.0(22)S.

A VRF must be defined prior to the configuration of this feature. An error message is displayed on the console if no VRF exists.

This document assumes that multiprotocol BGP (mBGP), Multiprotocol Label Switching (MPLS), and Cisco Express Forwarding are enabled in your network.

Restrictions for VRF Selection Using Policy-Based Routing

The VRF Selection Using Policy-Based Routing feature is supported only in service provider (-p-) images.

The VRF Selection Using Policy-Based Routing feature can coexist with the VRF Selection Based on Source IP address feature on the same router, but these features cannot be configured together on the same interface. This is designed behavior to prevent VRF table selection conflicts that could occur if these features were misconfigured together. An error message is displayed on the console if you attempt to configure the ip vrf select source and the ip policy route-map commands on the same interface.

Protocol Independent Multicast (PIM) and multicast packets do not support PBR and cannot be configured for a source IP address that is a match criterion for this feature.

The VRF Selection Using Policy-Based Routing feature cannot be configured with IP prefix lists.

Information About VRF Selection Using Policy-Based Routing

Before configuring VRF Selection Using Policy-Based Routing, you should understand the following concepts:

•Introduction to VRF Selection Using Policy-Based Routing

•Policy-Based Routing Set Clauses: Overview

Introduction to VRF Selection Using Policy-Based Routing

The VRF Selection Using Policy-Based Routing feature is an extension of the VRF Selection Based on Source IP Address feature. The PBR implementation of the VRF selection feature allows you to policy route VPN traffic based on match criteria. Match criteria are defined in an IP access list or based on packet length. The following match criteria are supported in Cisco IOS software:

•IP access lists—Define match criteria based on IP addresses, IP address ranges, and other IP packet access list filtering options. Named, numbered, standard, and extended access lists are supported. All IP access-list configuration options in Cisco IOS software can be used to define match criteria.

•Packet lengths—Define match criteria based on the length of a packet in bytes. The packet length filter is defined in a route map with the match length route-map configuration command.

Policy routing is defined in the route map. The route map is applied to the incoming interface with the ip policy route-map interface configuration command. An IP access list is applied to the route map with the match ip address route-map configuration command. Packet length match criteria are applied to the route map with the match length route-map configuration command. The set action is defined with the set vrf route-map configuration command. The match criteria are evaluated, and the appropriate VRF is selected by the set clause. This combination allows you to define match criteria for incoming VPN traffic and policy route VPN packets out to the appropriate VRF.

Policy-Based Routing Set Clauses: Overview

When you are configuring PBR, the following four set clauses can be used to change normal routing and forwarding behavior:

•set default interface

•set interface

•set ip default next-hop

•set ip next-hop

Configuring any of the set clauses will overwrite normal routing forwarding behavior of a packet.

The VRF Selection Using Policy-Based Routing feature introduces the fifth set clause that can be used to change normal routing and forwarding behavior. The set vrf command is used to select the appropriate VRF after the successful match occurs in the route map.

How to Configure VRF Selection Using Policy-Based Routing

This section contains the following procedures:

•Defining the Match Criteria for PBR VRF Selection (required)

•Configuring PBR VRF Selection in a Route Map (required)

•Configuring PBR on the Interface (required)

•Configuring IP VRF Receive on the Interface (required)

•Verifying the Configuration of the VRF Selection Using Policy-Based Routing (optional)

Defining the Match Criteria for PBR VRF Selection

The match criteria for PBR VRF route selection are defined in an access list. Standard and named access lists are supported. The following sections explain how to configure PBR route selection:

•Configuring PBR VRF Selection with a Standard Access List (required)

•Configuring PBR VRF Selection with a Named Access List (required)

Match Criteria Defined Based on Packet Length

Match criteria can also be defined based on the packet length using the match length route-map configuration command. This configuration option is defined entirely within a route map.

Prerequisites

Before you perform this task, make sure that the VRF and associated IP address are already defined.

Configuring PBR VRF Selection with a Standard Access List

Use the following commands to create a standard access list and define the PBR VRF route selection match criteria in it in order to permit or deny the transmission of VPN traffic data packets.

SUMMARY STEPS

1. enable  

2. configure terminal  

3. access-list access-list-number {deny | permit} source-addr [source-wildcard] [log]  

DETAILED STEPS

	Command or Action	Purpose
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	access-list access-list-number {deny | permit} source-addr [source-wildcard] [log] Example: Router(config)# access-list 40 permit 192.168.1.0 0.0.0.255	Creates an access list and defines the match criteria for the route map. •Match criteria can be defined based on IP addresses, IP address ranges, and other IP packet access-list filtering options. Named, numbered, standard, and extended access lists are supported. All IP access list configuration options in Cisco IOS software can be used to define match criteria. •The example creates a standard access list numbered 40. This filter will permit traffic from any host with an IP address in the 192.168.1.0/24 subnet.

Configuring PBR VRF Selection with a Named Access List

Use the following commands to define the PBR VRF route selection match criteria in a named access list in order to permit or deny the transmission of VPN traffic data packets.

SUMMARY STEPS

1. enable  

2. configure terminal  

3. ip access-list {standard | extended} [access-list-name | access-list-number]  

4. [sequence-number] {permit | deny} protocol source-addr source-wildcard destination-addr destination-wildcard [option option-value] [precedence precedence] [tos tos] [log] [time-range time-range-name] [fragments]  

DETAILED STEPS

	Command or Action	Purpose
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 access-list {standard | extended} [access-list-name | access-list-number] Example: Router(config)# ip access-list extended NAMEDACL	Specifies the IP access list type and enters the corresponding access-list configuration mode. •A standard, extended, or named access list can be used.
Step 4	[sequence-number] {permit | deny} protocol source-addr source-wildcard destination-addr destination-wildcard [option option-value][precedence precedence] [tos tos] [log] [time-range time-range-name] [fragments] Example: Router(config-ext-nacl)# permit ip any any option any-options	Defines the criteria for which the access list will permit or deny packets. •Match criteria can be defined based on IP addresses, IP address ranges, and other IP packet access-list filtering options. Named, numbered, standard, and extended access lists are supported. All IP access-list configuration options in Cisco IOS software can be used to define match criteria. •The example creates a named access list that permits any configured IP option.

Configuring PBR VRF Selection in a Route Map

Use the following commands to configure the VRF through which the outbound VPN packets will be policy routed in order to permit or deny the transmission of VPN traffic data packets.

Incoming packets are filtered through the match criteria that are defined in the route map. After a successful match occurs, the set vrf command configuration determines the VRF through which the outbound VPN packets will be policy routed.

Prerequisites

•The VRF must be defined prior to the configuration of the route map; otherwise an error message is displayed on the console.

•A receive entry must be added to the VRF selection table with the ip vrf receive command. If a match and set operation occurs in the route map but there is no receive entry in the local VRF table, the packet will be dropped if the packet destination is local.

Restrictions

None.

SUMMARY STEPS

1. enable  

2. configure terminal  

3. route-map map-tag [permit | deny] [sequence-number]  

4. match ip address {acl-number [acl-number ... | acl-name ...] | acl-name

[acl-name ... | acl-number ...]}

or

match length minimum-length maximum-length  

5. set vrf vrf-name

6. exit

DETAILED STEPS

	Command or Action	Purpose
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	route-map map-tag [permit | deny] [sequence-number] Example: Router(config)# route-map map1 permit 10	Enters route map configuration mode. Defines the conditions for redistributing routes from one routing protocol into another, or enables policy routing.
Step 4	match ip address {acl-number [acl-number ... | acl-name ...] | acl-name [acl-name ... | acl-number ...]} or match length minimum-length maximum-length Example: Router(config-route-map)# match ip address 1 or Example: Router(config-route-map)# match length 3 200	Distributes any routes that have a destination network number address that is permitted by a standard or extended access list, and performs policy routing on matched packets. •IP access lists are supported. •The example configures the route map to use standard access list 1 to define match criteria. or Specifies the Layer 3 packet length in the IP header as a match criterion in a class map. •The example configures the route map to match packets that are 3 to 200 bytes in size.
Step 5	set vrf vrf-name Example: Router(config-route-map)# set vrf map1	Defines which VRF to route VPN packets that are successfully matched in the same route map sequence for PBR VRF selection. •The example policy routes matched packets out to the VRF named map1.
Step 6	exit Example: Router(config-route-map)# exit	Exits route-map configuration mode and enters global configuration mode.

Configuring PBR on the Interface

Use the following commands to filter incoming VPN traffic data packets. Incoming packets are filtered through the match criteria that are defined in the route map.

The route map is applied to the incoming interface. The route map is attached to the incoming interface with the ip policy route-map global configuration command.

Restrictions

•The VRF Selection Using Policy-Based Routing feature can coexist with the VRF Selection Based on Source IP address feature on the same router, but the two features cannot be configured together on the same interface. This is designed behavior to prevent VRF table selection conflicts that could occur if these features were misconfigured together. An error message is displayed on the console if you attempt to configure the ip vrf select source and the ip policy route-map commands on the same interface.

SUMMARY STEPS

1. enable  

2. configure terminal

3. interface type number [name-tag]

4. ip policy route-map map-tag

5. ip vrf receive vrf-name  

6. exit

DETAILED STEPS

	Command or Action	Purpose
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	interface type number [name-tag] Example: Router(config)# interface FastEthernet 0/1	Configures an interface and enters interface configuration mode.
Step 4	ip policy route-map map-tag Example: Router(config-if)# ip policy route-map map1	Identifies a route map to use for policy routing on an interface. •The configuration example attaches the route map named map1 to the interface.
Step 5	ip vrf receive vrf-name Example: Router(config-if)# ip vrf receive VRF1	Adds the IP addresses that are associated with an interface into the VRF table. •This command must be configured for each VRF that will be used for VRF selection.
Step 6	exit Example: Router(config-if)# exit	Exits interface configuration mode and enters global configuration mode.

Configuring IP VRF Receive on the Interface

Use the following commands to insert the IP address of an interface as a connected route entry in a VRF routing table. This will prevent dropped packets.

The source IP address must be added to the VRF selection table. VRF selection is a one-way (unidirectional) feature. It is applied to the incoming interface. If a match and set operation occurs in the route map but there is no VRF receive entry in the local VRF table, the packet will be dropped if the packet destination is local.

SUMMARY STEPS

1. enable  

2. configure terminal  

3. interface type number [name-tag]  

4. ip policy route-map map-tag  

5. ip vrf receive vrf-name  

6. end  

DETAILED STEPS

	Command	Purpose
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	interface type number [name-tag] Example: Router(config)# interface FastEthernet 0/1	Configures an interface and enters interface configuration mode.
Step 4	ip policy route-map map-tag Example: Router(config-if)# ip policy route-map map1	Identifies a route map to use for policy routing on an interface. •The configuration example attaches the route map named map1 to the interface.
Step 5	ip vrf receive vrf-name Example: Router(config-if)# ip vrf receive VRF1	Adds the IP addresses that are associated with an interface into the VRF table. •This command must be configured for each VRF that will be used for VRF selection.
Step 6	end Example: Router(config-if)# end	Exits interface configuration mode, and enters privileged EXEC mode.

Verifying the Configuration of the VRF Selection Using Policy-Based Routing

To verify the configuration of the VRF Selection Using Policy-Based Routing feature, perform each of the following steps in this section in the order specified.

SUMMARY STEPS

1. enable  

2. show ip access-list [access-list-number | access-list-name]

3. show route-map [map-name]

4. show ip policy  

DETAILED STEPS

	Command or Action	Purpose
Step 1	enable Example: Router> enable	Enables privileged EXEC mode. •Enter your password if prompted.
Step 2	show ip access-list [access-list-number | access-list-name] Example: Router# show ip access-list	Displays the contents of all current IP access lists. •This command is used to verify the match criteria that are defined in the access list. Both named and numbered access lists are supported.
Step 3	show route-map [map-name] Example: Router# show route-map	Displays all route maps configured or only the one specified. •This command is used to verify match and set clauses within the route map.
Step 4	show ip policy Example: Router# show ip policy	Displays the route map used for policy routing. •This command can be used to display the route map and the associated interface.

Configuration Examples for VRF Selection Using Policy-Based Routing

This section provides the following configuration examples:

•Defining PBR VRF Selection in Access List: Example

•Verifying VRF Selection Using Policy-Based Routing: Example

Defining PBR VRF Selection in Access List: Example

In the following example, three standard access lists are created to define match criteria for three different subnets. Any packets received on the Ethernet 0/1 interface will be policy routed through the PBR-VRF-Selection route map to the VRF that is matched in the same route map sequence. If the source IP address of the packet is part of the 10.1.0.0/24 subnet, VRF1 will be used for routing and forwarding.

access-list 40 permit 10.1.0.0 0.0.255.255

access-list 50 permit 10.2.0.0 0.0.255.255

access-list 60 permit 10.3.0.0 0.0.255.255

route-map PBR-VRF-Selection permit 10

 match ip address 40

 set vrf VRF1

 !

route-map PBR-VRF-Selection permit 20

 match ip address 50

 set vrf VRF2

 !

route-map PBR-VRF-Selection permit 30

 match ip address 60

 set vrf VRF3

 !

interface Ethernet0/1

 ip address 192.168.1.6 255.255.255.252

 ip policy route-map PBR-VRF-Selection

 ip vrf receive VRF1

 ip vrf receive VRF2

 ip vrf receive VRF3 

Verifying VRF Selection Using Policy-Based Routing: Example

The following verification examples show defined match criteria and route-map policy configuration.

Verifying Match Criteria

To verify the configuration of match criteria for PBR VRF selection, use the show ip access-list command.

The following show ip access-list command output displays three subnet ranges defined as match criteria in three standard access lists:

Router# show ip access-list

Standard IP access list 40

    10 permit 10.1.0.0, wildcard bits 0.0.255.255

Standard IP access list 50

    10 permit 10.2.0.0, wildcard bits 0.0.255.255

Standard IP access list 60

    10 permit 10.3.0.0, wildcard bits 0.0.255.255

Verifying Route-Map Configuration

To verify route-map configuration, use the show route-map command. The output displays the match criteria and set action for each route-map sequence. The output also displays the number of packets and bytes that have been policy routed per each route-map sequence.

Router# show route-map

route-map PBR-VRF-Selection, permit, sequence 10

  Match clauses:

    ip address (access-lists): 40 

  Set clauses:

    vrf VRF1

  Policy routing matches: 0 packets, 0 bytes

route-map PBR-VRF-Selection, permit, sequence 20

  Match clauses:

    ip address (access-lists): 50 

  Set clauses:

    vrf VRF2

  Policy routing matches: 0 packets, 0 bytes

route-map PBR-VRF-Selection, permit, sequence 30

  Match clauses:

    ip address (access-lists): 60 

  Set clauses:

    vrf VRF3

  Policy routing matches: 0 packets, 0 bytes

Verifying PBR VRF Selection Policy

The following show ip policy command output displays the interface and associated route map that is configured for policy routing:

Router# show ip policy

Interface      Route map

Ethernet0/1        PBR-VRF-Selection

Additional References

The following sections provide references related to the MPLS VPN: VRF Selection Using Policy-Based Routing feature.

Related Documents

Related Topic	Document Title
VRF selection based on the source IP address	Directing MPLS VPN Traffic Using a Source IP Address

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 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 standards has not been modified by this feature.	—

Technical Assistance

Description

Link

The Cisco Support website provides extensive online resources, including documentation and tools for troubleshooting and resolving technical issues with Cisco products and technologies. To receive security and technical information about your products, you can subscribe to various services, such as the Product Alert Tool (accessed from Field Notices), the Cisco Technical Services Newsletter, and Really Simple Syndication (RSS) Feeds. Access to most tools on the Cisco Support website requires a Cisco.com user ID and password.

http://www.cisco.com/techsupport

Command Reference

The following commands are introduced or modified in the feature or features documented in this module. For information about these commands, see the Cisco IOS MPLS Command Reference at http://www.cisco.com/en/US/docs/ios/mpls/command/reference/mp_book.html. For information about all Cisco IOS commands, use the Command Lookup Tool at http://tools.cisco.com/Support/CLILookup or the Cisco IOS Master Command List, All Releases, at http://www.cisco.com/en/US/docs/ios/mcl/allreleasemcl/all_book.html.

•ip vrf receive

•set vrf

Feature Information for VRF Selection Using Policy-Based Routing

Table 1 lists the release history for this feature.

Not all commands may be available in your Cisco IOS software release. For release information about a specific command, see the command reference documentation.

Use Cisco Feature Navigator to find information about platform support and software image support. Cisco Feature Navigator enables you to determine which Cisco IOS and Catalyst OS software images support a specific software release, feature set, or platform. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.

---

Note Table 1 lists only the Cisco IOS software release that introduced support for a given feature in a given Cisco IOS software release train. Unless noted otherwise, subsequent releases of that Cisco IOS software release train also support that feature.

---

Table 1 Feature Information for VRF Selection Using Policy-Based Routing

Feature Name	Releases	Feature Information
MPLS VPN: VRF Selection Using Policy-Based Routing	12.3(7)T 12.2(25)S 12.2(33)SRB 12.2(33)SXI	The MPLS VPN: VRF Selection Using Policy-Based Routing feature is an extension of the MPLS VPN: VRF Selection Based on Source IP Address feature. This feature introduces a policy-based routing (PBR) mechanism to classify and forward Virtual Private Network (VPN) traffic based on multiple VPN routing and forwarding (VRF) selection match criteria. In 12.3(7)T, this feature was introduced. This feature was integrated into Cisco IOS Release 12.2(25)S. This feature was integrated into Cisco IOS Release 12.2(33)SRB. This feature was integrated into Cisco IOS Release 12.2(33)SXI. The following commands were introduced or modified: ip vrf receive, set vrf.

Glossary

PBR—policy-based routing.

VPN—Virtual Private Network.

VRF—virtual routing and forwarding.

Cisco and the Cisco Logo are trademarks of Cisco Systems, Inc. and/or its affiliates in the U.S. and other countries. A listing of Cisco's trademarks can be found at www.cisco.com/go/trademarks. Third party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (1005R)

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

© 2004—2008 Cisco Systems, Inc. All rights reserved.