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Cisco IOS Software Releases 12.0 S

MPLS VPNs over IP Tunnels

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MPLS VPNs over IP Tunnels

Table Of Contents

MPLS VPNs over IP Tunnels

Contents

Prerequisites for the MPLS VPNs over IP Tunnels Feature

Supported Line Cards for the Cisco 12000 Series Internet Router

Supported Line Cards for the Cisco 10720 Internet Router

Restrictions for the MPLS VPNs over IP Tunnels Feature

MPLS VPNs over IP Tunnels Feature Information

Deploying Layer 3 VPNs Over Multipoint L2TPv3 Tunnels

Advertising Tunnel Type and Tunnel Capabilities Between PE Routers—BGP

Configuring the PE Routers and Managing Address Space

Packet Validation Mechanism

Configuring Quality of Service Using the Modular QoS CLI

MPLS VPN Carrier Supporting Carrier over IP Tunnels

BGP Multipath Load Sharing for MPLS VPNs over IP Tunnels

Configuring MPLS VPNs over IP Tunnels

Configuring a VRF for an L2TPv3 Tunnel

Configuring a Multipoint L2TPv3 Tunnel

Prerequisites

Troubleshooting

Configuring a Route Map for a Layer 3 VPN

Defining an Address Space and Configuring BGP

Configuring Tunnel Marking on an Encapsulation Interface

Mapping Tunnel Marking to QoS-group and Discard-Class

Configuring MPLS VPN Carrier Supporting Carrier over IP Tunnels

Prerequisites

Configuring the Backbone-Carrier PE Router

Configuring the Customer-Carrier PE Router

Verifying the VRF and RiV

Verifying the Multipoint L2TPv3 Tunnel

Verifying the Modular QoS CLI Configuration

Troubleshooting Tips

Verifying the MPLS VPN—Carrier Supporting Carrier Configuration

Configuration Examples for MPLS VPNs over IP Tunnels

Configuring the VRF and RiV—Example

Configuring the Multipoint L2TPv3 Tunnel—Example

Configuring a Route Map for the Layer 3 VPN—Example

Defining Address Space and Configuring BGP—Example

Configuring Tunnel Marking on the Encapsulation Interface—Example

Mapping Tunnel Marking to QoS-group and Discard-Class—Example

Configuring MPLS VPN Carrier Supporting Carrier over IP Tunnels—Examples

Configuration for an ISP Customer Carrier

Configuration for an MPLS VPN Customer Carrier

Verifying the VRF—Example

Verifying the Multipoint L2TPv3 Tunnel—Examples

Verifying QoS Configuration—Example

Verifying MPLS VPN Carrier Supporting Carrier over IP Tunnels—Example

Additional References

Related Documents

Standards

MIBs

RFCs

Technical Assistance

Command Reference

address-family ipv4—BGP

clear ip bgp

clear tunnel l3vpn l2tpv3

show ip bgp ipv4


MPLS VPNs over IP Tunnels


Part Number OL-8694-01 (Rev C0), September 26, 2006

The MPLS VPNs over IP Tunnels feature introduces the capability to deploy Layer 3 Virtual Private Network (VPN) services, as proposed in RFC 2547, BGP/MPLS VPNs, over an IP core network using L2TPv3 multipoint tunneling instead of Multiprotocol Label Switching (MPLS). This feature allows L2TPv3 tunnels to be configured as multipoint tunnels to transport IP VPN services across the core IP network. Because multipoint tunnels support multiple endpoints, only one tunnel must be configured on each Provider Edge (PE) router. This feature also introduces a simple packet validation mechanism to enforce VPN integrity.

Feature History for MPLS VPNs over IP Tunnels

Release
Modification

12.0(28)S

This feature was introduced.

12.0(30)S

Support for the Cisco 12000 Series Internet Router, the Route Processor (RP), and Performance Route Processor (PRP) was integrated into Cisco IOS Release 12.0(30)S.

12.0(31)S

Support for the MPLS VPNs over IP Tunnels feature was added on the Cisco 12000 series Internet router on the following interfaces:

2.5G ISE SPA Interface Processor (SIP):

2-Port T3/E3 Serial shared port adaptor (SPA)

4-Port T3/E3 Serial SPA

2-Port Channelized T3 SPA

4-Port Channelized T3 Serial SPA

Support for the MPLS VPN—Carrier Supporting Carrier (CsC) feature on interfaces configured for MPLS VPNs over IP Tunnels was added to IP Services Engine (ISE) line cards on the Cisco 12000 series Internet router.

12.0(31)S1

Support was added for Cisco 12000 series ISE line cards that are configured for external BGP (eBGP) and internal BGP (iBGP) multipath load balancing in a BGP MPLS-VPN network (see BGP Multipath Load Sharing for Both eBGP and iBGP in an MPLS-VPN).

12.0(32)S

Support for the Cisco 10720 Internet router was added.

12.0(32)SY

Support was added for Engine 5 shared port adapters (SPAs) and SPA Interface Processors (SIPs) on the Cisco 12000 series Internet router.

Support for E5 interfaces configured for eBGP and iBGP multipath load sharing in a BGP MPLS network was also added (see BGP Multipath Load Sharing for Both eBGP and iBGP in an MPLS-VPN).

Support for the MPLS VPN Carrier Supporting Carrier over IP Tunnels feature on customer-facing interfaces on the Cisco 10720 Internet router was added.


Finding Support Information for Platforms and Cisco IOS Software Images

To use Cisco Feature Navigator to find information about platform support and Cisco IOS software image support, go to http://www.cisco.com/go/fn. You must have an account on Cisco.com. If you do not have an account or have forgotten your username or password, click Cancel at the login dialog box and follow the instructions.

Contents

Prerequisites for the MPLS VPNs over IP Tunnels Feature

Restrictions for the MPLS VPNs over IP Tunnels Feature

MPLS VPNs over IP Tunnels Feature Information

Configuring MPLS VPNs over IP Tunnels

Configuration Examples for MPLS VPNs over IP Tunnels

Additional References

Command Reference

Prerequisites for the MPLS VPNs over IP Tunnels Feature

CEF or dCEF (for distributed platforms) must be enabled on all participating routers.

Supported Line Cards for the Cisco 12000 Series Internet Router

This section lists the Cisco 12000 series Internet router line cards that support the MPLS VPNs over IP Tunnels feature with backbone-facing interfaces (BFIs) in the network core and customer-facing interfaces (CFI) on the network edge.

Supported Backbone-Facing Interfaces

4-port OC-3 POS ISE

8-port OC-3 POS ISE

16-port OC-3 POS ISE

4-port OC-12 POS ISE

1-port OC-48 POS ISE

4-port GE ISE

IP Services Engine (ISE/Engine 3) shared port adapters (SPAs):

2-port channelized T3 to DS0

4-port channelized T3 to DS0

2-port T3/E3 Serial

4-port T3/E3 Serial

Engine 5 shared port adapters:

1-port channelized STM-1c/OC-3c to DS0

2-port channelized T3 to DS0

4-port channelized T3 to DS0

8-port channelized T1/E1

1-port 10-Gigabit Ethernet

2-port Gigabit Ethernet

5-port Gigabit Ethernet

10-port Gigabit Ethernet

8-port Fast Ethernet

8-port 10/100 Ethernet

4-port OC-3/STM4 POS

8-port OC-3/STM4 POS

2-port OC-12/STM4 POS

4-port OC-12/STM4 POS

8-port OC-12/STM4 POS

2-port OC-48/STM16 POS/RPR

1-port OC-192/STM64 POS/RPR VSR

1-port OC-192/STM64 POS/RPR SMLR

1-port OC-192/STM64 POS/RPR XFP

SPA Interface Processors (SIPs):

12000-SIP-400 (2.5G ISE SPA Interface Processor)

12000-SIP-600 (10G Engine 5 SPA Interface Processor)

12000-SIP-401 (2.5G multiservice engine SPA Interface Processor)

12000-SIP-501 (5G multiservice engine SPA Interface Processor)

12000-SIP-601 (10G multiservice engine SPA Interface Processor)

Supported Customer-Facing Interfaces

4-port OC-3 POS ISE

8-port OC-3 POS ISE

16-port OC-3 POS ISE

4-port OC-12 POS ISE

1-port OC-48 POS ISE

1-port channelized OC-12 (DS1) POS ISE

4-port OC-12 ATM ISE

4-port OC-3 ATM ISE

4-port GE ISE

IP Services Engine (ISE/Engine 3) shared port adapters (SPAs):

2-port channelized T3 to DS0

4-port channelized T3 to DS0

2-port T3/E3 Serial

4-port T3/E3 Serial

Engine 5 shared port adapters:

1-port channelized STM-1c/OC-3c to DS0

8-port channelized T1/E1

1-port 10-Gigabit Ethernet

2-port Gigabit Ethernet

5-port Gigabit Ethernet

10-port Gigabit Ethernet

8-port Fast Ethernet

8-port 10/100 Ethernet

4-port OC-3/STM4 POS

8-port OC-3/STM4 POS

2-port OC-12/STM4 POS

4-port OC-12/STM4 POS

8-port OC-12/STM4 POS

2-port OC-48/STM16 POS/RPR

1-port OC-192/STM64 POS/RPR

1-port OC-192/STM64 POS/RPR

1-port OC-192/STM64 POS/RPR

SPA Interface Processors (SIPs):

12000-SIP-400 (2.5G ISE SPA Interface Processor)

12000-SIP-600 (10G Engine 5 SPA Interface Processor

12000-SIP-401 (2.5G multiservice engine SPA Interface Processor)

12000-SIP-501 (5G multiservice engine SPA Interface Processor)

12000-SIP-601 (10G multiservice engine SPA Interface Processor)

Supported Line Cards for the Cisco 10720 Internet Router

This section describes the Cisco 10720 Internet router line cards that support the MPLS VPNs over IP Tunnels feature on backbone-facing and customer-facing interfaces.

Supported Backbone-Facing Interfaces on Uplink Cards

24-port 10/100 Fast Ethernet

4-port Gigabit Ethernet 8-port 10/100BASE-TX (Revision A and Revision B versions)

2-port OC-48c/STM-16c POS/SRP—Allows you to change Packet-over-SONET (POS) interfaces to Dynamic Packet Transport (DPT)/Spatial Reuse Protocol (SRP).

Dual Mode IEEE 802.17 RPR/SRP—Allows you to use the OC-48c/STM-16c interfaces in either SRP or Resilient Packet Ring (RPR)-IEEE mode.

Supported Customer-Facing Interfaces on Access Cards

24-port 10/100 Fast Ethernet

4-port Gigabit Ethernet 8-port 10/100BASE-TX (Revision A and Revision B versions)

802.1Q VLAN encapsulation is supported on these backbone-facing and customer-facing 10720 interfaces when they are configured as member interfaces of a Fast EtherChannel or Gigabit EtherChannel bundle.

For more information about supported line cards, see the Cross-Platform Release Notes for Cisco IOS Release 12.0 S.

Restrictions for the MPLS VPNs over IP Tunnels Feature

Configuring Static Routes

When you configure static routes in an MPLS or MPLS VPN network, some variations of the ip route and ip route vrf commands are not supported for the MPLS VPNs over IP Tunnels feature in the following trains of Cisco IOS software that support the Tag Forwarding Information Base (TFIB):

Cisco IOS Releases 12.xT

Cisco IOS Releases 12.xM

Cisco IOS Release 12.0S

The TFIB cannot resolve prefixes when the recursive route over which the prefixes travel disappears and then reappears. However, certain command variations are supported in Cisco IOS releases that support the MPLS Forwarding Infrastructure (MFI), such as Cisco IOS Release 12.2(25)S and later releases. Refer to Table 1 and Table 2 for the ip route and ip route vrf commands that are supported and not supported when configuring static routes in an MPLS environment.

Table 1 describes the ip route and ip route vrf commands that are supported to configure static routes in an IP core network configured for MPLS VPNs over IP Tunnels.

Table 1 Commands Supported for Configuring Static Routes in an MPLS VPNs over IP Tunnels Network

MPLS Configuration
Commands Supported to Configure Static Routes

Standard MPLS network

ip route destination-prefix mask interface next-hop-address

MPLS network in which you configure load sharing with static nonrecursive routes on an outbound interface

ip route destination-prefix mask interface1 next-hop1
ip route
destination-prefix mask interface2 next-hop2

MPLS VPN in which the next hop and interface are in the same Virtual Private Network (VPN) routing and forwarding (VRF) table

ip route vrf vrf-name destination-prefix mask next-hop-address

ip route vrf vrf-name destination-prefix mask interface next-hop-address

ip route vrf vrf-name destination-prefix mask interface1 next-hop1
ip route vrf vrf-name destination-prefix mask interface2 next-hop2

MPLS VPN in which the next hop is in the global routing table in the MPLS core network (for example, the internal gateway)

ip route vrf vrf-name destination-prefix mask next-hop-address global

ip route vrf vrf-name destination-prefix mask interface next-hop-address
(This command is supported when the next hop and interface are in the core IP network.)

MPLS VPN in which you configure load sharing with static nonrecursive routes on an outbound interface

ip route destination-prefix mask interface1 next-hop1
ip route
destination-prefix mask interface2 next-hop2

MPLS VPN in which the next hop is in the global routing table on a CE router (for example, when the IP route prefix for the destination is the loopback address of the CE router as in EBGP multihop cases)

ip route vrf vrf-name destination-prefix mask interface next-hop-address

MPLS VPN in which the next hop is in the global routing table on a CE router and in which you configure load sharing with static nonrecursive routes on an outbound interface

ip route destination-prefix mask interface1 nexthop1
ip route
destination-prefix mask interface2 nexthop2


Table 2 describes the ip route and ip route vrf commands that are not supported to configure static routes in an IP core network configured for MPLS VPNs over IP Tunnels.

Table 2 Commands Not Supported for Configuring Static Routes in an MPLS VPNs over IP Tunnels Network

MPLS Configuration
Commands Not Supported to Configure Static Routes

MPLS VPN in which the next hop is in the global routing table in the MPLS core network and in which you enable load sharing so that the next hop can be reached through two paths

ip route destination-prefix mask next-hop-address

MPLS VPN in which the next hop is in the global routing table in the MPLS core network and in which you enable load sharing so that the destination can be reached through two next hops

ip route vrf destination-prefix mask next-hop1 global
ip route vrf destination-prefix mask next-hop2 global

MPLS VPN that uses TFIB and in which the next hop and interface are in the same VRF table

ip route vrf vrf-name destination-prefix mask next-hop1
ip route vrf
vrf-name destination-prefix mask next-hop2


MPLS VPNs over IP Tunnels Feature Information

Deploying Layer 3 VPNs Over Multipoint L2TPv3 Tunnels

Advertising Tunnel Type and Tunnel Capabilities Between PE Routers—BGP

Configuring the PE Routers and Managing Address Space

Packet Validation Mechanism

Configuring Quality of Service Using the Modular QoS CLI

MPLS VPN Carrier Supporting Carrier over IP Tunnels

BGP Multipath Load Sharing for MPLS VPNs over IP Tunnels

Deploying Layer 3 VPNs Over Multipoint L2TPv3 Tunnels

VPN services are traditionally deployed over IP core networks by configuring MPLS or through L2TPv3 tunnels using point-to-point links. This feature introduces the capability to deploy Layer 3 VPN services by configuring multipoint L2TPv3 tunnels over an existing IP core network. This feature is configured only on PE routers and requires no configuration on the core routers.

The L2TPv3 multipoint tunnel network allows Layer 3 VPN services to be carried through the core without the configuration of MPLS. L2TPv3 multipoint tunnelling supports multiple tunnel endpoints, which creates a full mesh topology that requires only one tunnel to be configured on each PE router. This feature provides the capability for VPN traffic to be carried from enterprise networks across cooperating service provider core networks to remote sites.

Advertising Tunnel Type and Tunnel Capabilities Between PE Routers—BGP

Border Gateway Protocol (BGP) is used to advertise the tunnel endpoints and the subaddress family identifier (SAFI) specific attributes (which contains the tunnel type, and tunnel capabilities). This feature introduces the tunnel SAFI and the BGP SAFI-Specific Attribute (SSA) attribute.

The tunnel SAFI:

Defines the tunnel endpoint and carries the endpoint IPv4 address and next hop.

Is identified by the SAFI number 64.

The BGP SSA:

Carries the BGP preference and BGP flags. It also carries the tunnel cookie, tunnel cookie length, and session ID.

Is identified by attribute number 19.

These attributes allow BGP to distribute tunnel encapsulation information between PE routers. VPNv4 traffic is routed through these tunnels. The next hop, advertised in BGP VPNv4 updates, determines which tunnel to use for routing tunnel traffic.

Configuring the PE Routers and Managing Address Space

One multipoint L2TPv3 tunnel is configured on each PE router. To create the VPN, configure a unique Virtual Routing and Forwarding (VRF) instance. The tunnel that transports the VPN traffic across the core network resides in its own address space. A special purpose VRF called a Resolve in VRF (RiV) is created to manage the tunnel address space. You also configure the address space under the RiV that is associated with the tunnel and a static route in the RiV to route outgoing traffic through the tunnel.

Packet Validation Mechanism

The MPLS VPNs over IP Tunnels feature provides a simple mechanism to validate received packets from appropriate peers. The multipoint L2TPv3 tunnel header is automatically configured with a 64-bit cookie and L2TPv3 session ID. This packet validation mechanism protects the VPN from illegitimate traffic sources, such as injecting a rogue packet into the tunnel to gain access to the VPN. The cookie and session ID are not user-configurable; however, they are visible in the packet as it is routed between the two tunnel endpoints. This packet validation mechanism does not protect the VPN from hackers who have the ability to monitor legitimate traffic between PE routers.

Configuring Quality of Service Using the Modular QoS CLI

To configure the bandwidth on the encapsulation and decapsulation interfaces, use the modular QoS CLI (MQC). This task is optional.

Use the MQC to configure the IP precedence or Differentiated Services Code Point (DSCP) value set in the IP carrier header during packet encapsulation. To set these values, enter a standalone set command or a police command using the keyword tunnel. In the input policy on the encapsulation interface, you can set the precedence or DSCP value in the IP payload header by using MQC commands without the keyword tunnel.


Note You must attach a QoS policy to the physical interface—not to the tunnel interface.


If Modified Deficit Round Robin (MDRR)/Weighted Random Early Detection (WRED) is configured for the encapsulation interface in the input direction, the final value of the precedence or DSCP field in the IP carrier header is used to determine the precedence class for which the MDRR/WRED policy is applied. On the decapsulation interface in the input direction, you can configure a QoS policy based on the precedence or DSCP value in the IP carrier header of the received packet. In this case, an MQC policy with a class to match on precedence or DSCP value will match the precedence or DSCP value in the received IP carrier header.

Similarly, the precedence class for which the MDRR/WRED policy is applied on the decapsulation input direction is also determined by precedence or DSCP value in the IP carrier header.

MPLS VPN Carrier Supporting Carrier over IP Tunnels

You can configure the MPLS VPN—Carrier Supporting Carrier (CsC) feature on the following interfaces that are configured for the MPLS VPNs over IP Tunnels feature:

IP Services Engine (ISE) and Engine 5 interfaces on a Cisco 12000 series Internet router

Fast Ethernet and Gigabit Ethernet interfaces on a Cisco 10720 Internet router

The router must be deployed as a PE router in a service-provider core network. The MPLS VPN Carrier Supporting Carrier over IP Tunnels feature is supported only on customer-facing interfaces.


Note For information about the ISE and Engine 5 shared port adaptors (SPAs) and SPA interface processors (SIPs) supported on Cisco 12000 series routers, refer to the Cisco 12000 Series Routers SPA Hardware Installation Guide.


The MPLS VPN Carrier Supporting Carrier over IP Tunnels feature enables one MPLS VPNs over IP Tunnel-based service provider to allow other service providers to use a segment of its backbone network.

Backbone carrier—Service provider that provides the segment of the backbone network to the other provider

Customer carrier—Service provider that uses the segment of the backbone network

The backbone carrier benefits in the following ways:

The backbone carrier can accommodate either IP or MPLS VPN traffic from many customer carriers (including labelled customer traffic) and give them access to its MPLS VPNs over IP Tunnels-backbone. The backbone carrier does not need to create and maintain separate backbones for its customer carriers. Using one multipoint L2TPv3 tunnel for each customer carrier simplifies the backbone carrier's VPN operations.

The MPLS VPN Carrier Supporting Carrier over IP Tunnels feature is scalable. You can change the tunnel configuration for a customer carrier to meet changing bandwidth and connectivity needs. The feature can accommodate unplanned growth and changes to enable tens of thousands of VPNs to be set up over the same MPLS VPNs over IP Tunnels network. A service provider can offer both VPN and Internet services.

The MPLS VPN—Carrier Supporting Carrier feature focuses on a backbone carrier that offers Border Gateway Protocol and Multiprotocol Label Switching (BGP/MPLS) VPN services.

When you configure the MPLS VPN—Carrier Supporting Carrier feature on a Cisco 12000 series Internet router, the customer carrier can be either:

An Internet service provider (ISP)

A BGP/MPLS VPN service provider

For sample configurations of the MPLS VPN—Carrier Supporting Carrier feature for each type of customer carrier, see Configuring MPLS VPN Carrier Supporting Carrier over IP Tunnels—Examples.

When configured on a Cisco 10720 Internet router, the MPLS VPN—Carrier Supporting Carrier feature supports only customer-carrier VPNs that are configured as an MPLS VPN over IP Tunnels network.

For information about configuring a backbone carrier for the Carrier Supporting Carrier feature to allow other service providers to use a segment of its backbone network, refer to:

MPLS VPN—Carrier Supporting Carrier (using the Label Distribution Protocol (LDP) to carry the MPLS labels and an Internal Gateway Protocol (IGP) to carry the routes between PE and CE routers)

MPLS VPN—Carrier Supporting Carrier—IPv4 BGP Label Distribution (using the Border Gateway Protocol (BGP) to transport routes and MPLS labels between the PE routers and CE routers using multiple paths)

BGP Multipath Load Sharing for MPLS VPNs over IP Tunnels

You can configure external BGP (eBGP) and internal BGP (iBGP) multipath load balancing on the following customer-facing interfaces that are configured for the MPLS VPNs over IP Tunnels feature:

IP Services Engine (ISE) interfaces on a Cisco 12000 series Internet router

Engine 5 interfaces on shared port adapters (SPAs) on a Cisco 12000 series Internet router

The BGP Multipath Load Sharing for eBGP and iBGP feature:

Allows you to configure multipath load balancing with both external BGP and internal BGP paths in BGP networks that are configured to use MPLS VPNs. When faced with multiple routes to the same destination, BGP chooses the best route for routing traffic toward the destination so that no individual router is overburdened.

Is useful for multi-homed autonomous systems and PE routers that import both eBGP and iBGP paths from multihomed and stub networks.

For information about how to configure and use BGP multipath load sharing for both eBGP and iBGP paths, refer to BGP Multipath Load Sharing for Both eBGP and iBGP in an MPLS-VPN.

Configuring MPLS VPNs over IP Tunnels

To deploy Layer 3 VPN services over multipoint L2TPv3 tunnels, you create a VRF instance, create the multipoint L2TPv3 tunnel, redirect the VPN IP traffic to the tunnel, and configure the BGP VPNv4 exchange so that BGP updates are filtered through a route-map and prefixes are resolved in the VRF table. The configuration steps are described in the following sections:

Configuring a VRF for an L2TPv3 Tunnel

Configuring a Multipoint L2TPv3 Tunnel

Configuring a Route Map for a Layer 3 VPN

Defining an Address Space and Configuring BGP

Configuring Tunnel Marking on an Encapsulation Interface

Mapping Tunnel Marking to QoS-group and Discard-Class

Configuring MPLS VPN Carrier Supporting Carrier over IP Tunnels

Verifying the VRF and RiV

Verifying the Multipoint L2TPv3 Tunnel

Verifying the Modular QoS CLI Configuration

Verifying the MPLS VPN—Carrier Supporting Carrier Configuration

Configuring a VRF for an L2TPv3 Tunnel

The VPN is created by configuring a unique Virtual Routing and Forwarding (VRF) instance. The tunnel that transports the VPN traffic across the core network resides in its own address space. A special purpose VRF called a Resolve in VRF (RiV) is created to manage the tunnel address space.

SUMMARY STEPS

1. enable

2. configure terminal

3. ip vrf vrf-name

4. rd as-number:network-number | ip-address:network number

5. route-target import as-number:network-number | ip-address:network number

6. route-target export as-number:network-number | ip-address:network number

7. exit

8. ip vrf vrf-name

9. rd as-number:network-number | ip-address:network number

10. end

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 vrf vrf-name

Example:

Router(config)# ip vrf CUSTOMER_A

Creates a VRF routing table and specifies the VRF name (or tag).

The ip vrf command creates a VRF routing table and a CEF table, which are both named using the vrf-name argument. Associated with these tables is the default route-distinguisher value.

Step 4 

rd as-number:network-number | ip-address:network-number

Example:

Router(config-vrf)# rd 100:110

Creates routing and forwarding tables for the VRF instance created in Step 3.

There are two formats for configuring the route distinguisher argument. It can be configured in the as-number:network number (ASN:nn) format, as shown in the example, or it can be configured in the IP address:network number format (IP-address:nn).

Step 5 

route-target [export | import | both] as-number:network-number | ip-address:network-number

Example:

Router(config-vrf)# route-target import 100:1000

Imports routing information from the target VPN extended community.

Step 6 

route-target [export | import | both] as-number:network-number | ip-address:network-number

Example:

Router(config-vrf)# route-target export 100:1000

Exports routing information to the target VPN extended community.

Step 7 

exit

Example:

Router(config-vrf)# exit

Exits VRF configuration mode and enters global configuration mode.

Step 8 

ip vrf vrf-name

Example:

Router(config)# ip vrf MY_RIV

Creates the special Resolve in VRF (RiV) VRF instance and table that will be used for the tunnel and redirection of the IP address.

Creates a VRF routing table and specifies the VRF name (or tag). The ip vrf command creates a VRF routing table and a CEF table; both are named using the vrf-name argument. Associated with these tables is the default route-distinguisher value.

Step 9 

rd as-number:network-number | ip-address:network-number

Example:

Router(config-vrf)# rd 1:1

Creates routing and forwarding tables for the VRF instance created in Step 8.

There are two formats for configuring the route distinguisher argument. It can be configured in the as-number:network number (ASN:nn) format, as shown in the example, or it can be configured in the IP address:network number format (IP-address:nn).

Step 10 

end

Example:

Router(config-vrf)# end

Exits VRF configuration mode and enters privileged EXEC mode.

Proceed to the next task "Configuring a Multipoint L2TPv3 Tunnel."

Configuring a Multipoint L2TPv3 Tunnel

Border Gateway Protocol (BGP) is used to advertise the tunnel type, tunnel capabilities, and tunnel-specific attributes. BGP is also used to distribute VPNv4 routing information between PE routers on the edge of the network, which maintains peering relationships between the VPN service and VPN sites. The next hop advertised in BGP VPNv4 updates triggers tunnel endpoint discovery.

Prerequisites

The IP address of the interface, specified as the tunnel source, should match the IP address used by BGP as the next hop for the VPNv4 update. The BGP configuration will include the neighbor ip-address update-source loopback 0 command.

SUMMARY STEPS

1. enable

2. configure {terminal | memory | network}

3. interface tunnel interface-number

4. ip vrf forwarding RiV-name

5. ip address ip-address subnet-mask

6. tunnel source loopback interface-number

7. tunnel mode l3vpn l2tpv3 multipoint

8. end

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 

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3 

interface tunnel interface-number

Example:

Router(config)# interface tunnel 1

Enters interface configuration mode, and creates the tunnel.

Step 4 

ip vrf forwarding RiV-name

Example:

Router(config-if)# ip vrf forwarding MY_RIV

Associates the VRF with an interface or the subinterface.

The RiV name is configured for the VRF argument in this step.

Step 5 

ip address ip-address subnet-mask

Example:

Router(config-if)# ip-address 172.16.1.3 255.255.255.255

Specifies the IP address for the tunnel.

Step 6 

tunnel source loopback interface-number

Example:

Router(config-if)# tunnel source loopback 0

Associates the tunnel source IP address with the loopback interface.

Step 7 

tunnel mode l3vpn l2tpv3 multipoint

Example:

Router(config-if)# tunnel mode l3vpn l2tpv3 multipoint

Sets the mode for the Layer 3 VPN tunnel as l2tpv3 multipoint.

Step 8 

end

Example:

Router(config-if)# end

Exits interface configuration mode and enters privileged EXEC mode.

Troubleshooting

To generate and distribute a new L2TPv3 session for a Layer 3 VPN, use the clear tunnel l3vpn l2tpv3 command. This command is issued on the PE router. The hold-time argument is used to configure the amount of time that the existing session remains valid, while the new session is propagated to peers. The default value for the hold-time argument is 15 seconds. This is enough time for most networks. However, this value can be increased if it takes longer for the new session to propagate to all other PE routers.

Proceed to the next task "Configuring a Route Map for a Layer 3 VPN."

Configuring a Route Map for a Layer 3 VPN

Configure a route map to set the next hop to be resolved within the VRF table.

SUMMARY STEPS

1. enable

2. configure {terminal | memory | network}

3. route-map map-name

4. set ip next-hop in-vrf RiV-name

5. end

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 

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3 

route-map map-name [permit|deny] [sequence-number]

Example:

Router(config)# route-map SELECT_UPDATE_FOR_L3VPN permit 10

Enters route-map configuration mode, and creates a route-map.

Step 4 

set ip next-hop in-vrf RiV-name

Example:

Router(config-route-map)# set ip next-hop in-vrf MY_RIV

Specifies that the next hop is to be resolved in the VRF table for the specified VRF.

The RiV is configured for the VRF argument in this step.

Step 5 

end

Example:

Router(config-if)# end

Exits route-map configuration mode and enters privileged EXEC mode.

Proceed to the next task "Defining an Address Space and Specifying Address Resolution."

Defining an Address Space and Configuring BGP

Use the configuration task procedure in this section to set up the BGP VPNv4 exchange so that the updates are filtered through a route-map and interesting prefixes are resolved in the VRF table. The tunnel that transports the VPN traffic across the BGP core network resides in its own address space. The RiV is specified in this configuration to direct packet forwarding and next hop resolution.

SUMMARY STEPS

1. enable

2. configure {terminal | memory | network}

3. ip route vrf riv-vrf-name o.o.o.o o.o.o.o tunnel interface-number

4. router bgp as-number

5. neighbor ip-address | peer-group-name remote-as as-number

6. neighbor ip-address | peer-group-name update-source interface-type

7. address-family vpnv4 [unicast]

8. neighbor ip-address | peer-group-name activate

9. neighbor ip-address | peer-group-name route-map map-name {in | out}

10. exit-address-family

11. address-family ipv4 [tunnel]

12. neighbor ip-address | peer-group-name activate

13. end

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 

configure {terminal | memory | network}

Example:

Router# configure terminal

Enters global configuration mode.

Step 3 

ip route vrf riv-vrf-name 0.0.0.0 0.0.0.0 tunnel n

Example:

Router(config)# ip route vrf MY_RIV 0.0.0.0 0.0.0.0 tunnel 1

Sets the packet forwarding to the Resolve-in-VRF (RiV).

Note A 0.0.0.0 0.0.0.0 default route must be configured for the RiV. If the default route is not configured, the next hop may not be resolvable.

Step 4 

router bgp as-number

Example:

Router (config)# router bgp 100

Specifies the number of an autonomous system that identifies the router to other BGP routers and tags the routing information passed along.

Step 5 

neighbor {ip-address | peer-group-name} remote-as as-number

Example:

Router(config-router)# neighbor 172.16.1.2 remote-as 100

Adds an entry to the BGP or multiprotocol BGP neighbor table.

Step 6 

neighbor {ip-address | peer-group-name} update-source interface-type

Example:

Router(config-router)# neighbor 172.16.1.2 update-source Loopback 0

Specifies a specific operational interface that BGP sessions use for TCP connections.

Step 7 

address-family vpnv4 [unicast]

Example:

Router(config-router)# address-family vpnv4 unicast

Specifies address family configuration mode for configuring routing sessions, such as BGP, that use standard VPNv4 address prefixes.

Step 8 

neighbor {ip-address | peer-group-name} activate

Example:

Router(config-router-af)# neighbor 172.16.1.2 activate

Enables the exchange of information with a neighboring router. Use the neighbor activate command in address family configuration or router configuration mode

Step 9 

neighbor {ip-address | peer-group-name} route-map map-name {in | out}

Example:

Router(config-router-af)# neighbor 172.16.1.2 route-map SELECT_UPDATE_FOR_L3VPN in

Applies a route map to incoming or outgoing routes. Use once for each inbound route.

Step 10 

exit-address-family

Example:

Router(config-router-af)# exit-address-family

Exits address family configuration mode, and enters router configuration mode.

Step 11 

address-family ipv4 [tunnel]

Example:

Router(config-router)# address-family ipv4 tunnel

Enter address family configuration mode for the IPv4 tunnel SAFI.

The configuration of this SAFI allows BGP to advertise the tunnel endpoints and SAFI specific attribute (which contains the tunnel type and the tunnel capabilities) between the PE routers.

Note Redistribution is enabled automatically within this SAFI.

Step 12 

neighbor {ip-address | peer-group-name} activate

Example:

Router(config-router-af)# neighbor 172.16.1.2 activate

Enables the exchange of information with a neighboring router. Use the neighbor activate command in address family configuration or router configuration mode

Step 13 

end

Example:

Router(config-router-af)# end

Exits address-family configuration mode and enters privileged EXEC mode.

Proceed to the next task "Configuring Tunnel Marking on an Encapsulation Interface."

Configuring Tunnel Marking on an Encapsulation Interface

QoS can optionally be configured to control bandwidth. As part of encapsulation, the precedence or Differentiated Services Code Point (DSCP) value in the IP carrier header can be set using the MQC. This can be achieved by configuring a standalone set action or by configuring a policing action using the keyword tunnel. In the input policy on the encapsulation interface, the precedence or DSCP value in the IP payload header can be set using MQC commands without using the keyword tunnel. Sample configurations appear below.


Note The policy must be attached to the physical interface—not the tunnel interface.


If Modified Deficit Round Robin (MDRR)/Weighted Random Early Detection (WRED) is configured for the encapsulation interface in the input direction, the final value of the precedence or DSCP field in the IP carrier header is used to determine the precedence class for which the MDRR/WRED policy is applied.

Release 12.0(32)SY adds scaled QoS capabilities on the Cisco 12000 platform by manipulating the tunnel header on the ingress PE. This will allow you to provide transparent QoS services by deliver end-to-end QoS enabled MVPN services,

SUMMARY STEPS

1. enable

2. configure terminal

3. policy-map policy-map-name

4. class {class-name | class-default}

5. set ip dscp tunnel dscp-value

or

set ip precedence tunnel precedence-value

or

police bps [burst-normal] [burst-max] conform-action action exceed-action action

6. exit  

7. exit  

8. interface type number [name-tag]

9. description string  

10. ip vrf forwarding vrf-name

11. ip address ip-address mask [secondary]

12. service-policy {input | output} policy-map-name

13. end

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 

policy-map policy-map-name

Example:

Router(config)# policy-map set_prec_tun

Creates or modifies a policy map that can be attached to one or more interfaces to specify a service policy, and enters policy-map configuration mode.

Enter the policy map name.

Step 4 

class {class-name | class-default}

Example:

Router(config-pmap)# class class-default

Specifies the name of the class whose policy you want to create or change, or specifies the default class (commonly known as the class-default class) before you configure its policy. Also enters policy-map class mode.

Enter the class name or enter the class-default keyword.

Step 5 

set ip dscp tunnel dscp-value

Example:

Router(config-pmap-c)# set ip dscp tunnel 2

(Optional) Sets or marks the differentiated services code point (DSCP) value in the tunnel header on the ingress interface. The tunnel marking value is a number from 0 to 63 when configuring DSCP.

Enter the tunnel value.

 

or

set ip precedence tunnel precedence-value

Example:

Router(config-pmap-c)# set ip precedence tunnel 2

(Optional) Sets or marks the IP precedence value in the tunnel header on the ingress interface. The tunnel marking value is a number from 0 to 7 when configuring IP precedence.

Enter the tunnel value.

 

or

police bps [burst-normal] [burst-max] conform-action action exceed-action action

Example:

Router(config-pmap-c)# police 1280000 conform-action set-dscp-tunnel-transmit 3

exceed-action drop


or

Router(config-pmap-c)# police cir 1280000 
conform-action set-prec-tunnel-transmit 3 
exceed-action drop

(Optional) Configures traffic policing on the basis of the bits per second (bps) specified and the actions specified.

If you use traffic policing in your network, you can implement the L2TPv3 tunnel marking feature with the set-dscp-tunnel-transmit or set-prec-tunnel-transmit traffic policing commands instead of the set ip dscp tunnel or the set ip precedence tunnel commands shown in Step 5.

The tunnel marking value for the traffic policing commands is from 0 to 63 when using set-dscp-tunnel-transmit and from 0 to 7 when using set-prec-tunnel-transmit.

Enter the bps, any optional burst sizes, and the desired conform and exceed actions.

Enter the set-dscp-tunnel-transmit or set-prec-tunnel-transmit commands after the conform-action keyword.

Note This is an example of one QoS feature you can configure at this step. Other QoS features include Weighted Random Early Detection (WRED), Weighted Fair Queueing (WFQ), and traffic shaping. Enter the command for the specific QoS feature you want to configure. For more information about QoS features, refer to Cisco IOS Quality of Service Solutions Configuration Guide, Release 12.3.

Step 6 

exit

Example:

Router(config-pmap-c)# exit

Exits policy-map class configuration mode and enters policy-map configuration mode.

Step 7 

exit

Example:

Router(config-pmap)# exit

Exits policy-map configuration mode and enters global configuration mode.

Step 8 

interface type number [name-tag]

Example:

Router(config)# interface POS0/0

Configures the interface type specified and enters interface configuration mode.

Enter interface type.

Step 9 

description string

Example:

Router(config-if)# description IP VPN Encapsulation - Customer Facing

Adds a description to the interface configuration.

Step 10 

ip vrf forwarding vrf-name

Example:

Router(config-if)# ip vrf forwarding IP_VPN

Associates the VRF with an interface or the subinterface.

Step 11 

ip address ip-address mask [secondary]

Example:

Router(config-if)# ip address 192.168.123.4 255.255.255.0

Sets a primary or secondary IP address for an interface.

Step 12 

service-policy {input | output} policy-map-name

Example:

Router(config-if)# service-policy input set_prec_tun

Specifies the name of the policy map to be attached to the input or output direction of the interface.

Policy maps can be configured on ingress or egress routers. They can also be attached in the input or output direction of an interface. The direction (input or output) and the router (ingress or egress) to which the policy map should be attached varies according your network configuration.

Enter the input keyword followed by the policy map name.

Note For this feature, only the incoming interface configured with the input keyword is supported.

Step 13 

end

Example:

Router(config-if)# end

(Optional) Exits interface configuration mode, and enters privileged EXEC mode.

Proceed to the next task "Mapping Tunnel Marking to Qos-group and Discard-Class."

Mapping Tunnel Marking to QoS-group and Discard-Class

On the decapsulation interface in the input direction, the QoS policy can be constructed based on the IP precedence or DSCP value in the IP carrier header of the received packet. In this case, an MQC policy with a class to match on precedence or DSCP value matches the IP precedence or DSCP value in the received IP carrier header.

Similarly, the IP precedence class (for which the MDRR/WRED policy is applied on the decapsulation input direction) is also determined by the IP precedence or DSCP value in the IP carrier header. Qos-group and discard-class values can then be used to construct an output policy for the Decapsulation interface to configure Modified Deficit Round Robin (MDRR)/Weighted Random Early Detection (WRED).

SUMMARY STEPS

1. enable

2. configure terminal

3. policy-map policy-map-name

4. class {class-name | class-default}

5. set qos-group {group-id}

6. set discard-class value

7. exit

8. exit

9. interface type number [name-tag]

10. description string

11. ip address ip-address mask [secondary]

12. no ip directed-broadcast [access-list-number] | [extended access-list-number]

13. service-policy {input | output} policy-map-name

14. end

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 

policy-map policy-map-name

Example:

Router(config)# policy-map set_qos_disc_from_prec

Creates or modifies a policy map that can be attached to one or more interfaces to specify a service policy, and enters policy-map configuration mode.

Enter the policy map name.

Step 4 

class {class-name | class-default}

Example:

Router(config-pmap)# class match_prec1

Specifies the name of the class whose policy you want to create or change, or specifies the default class (commonly known as the class-default class) before you configure its policy. Also enters policy-map class mode.

Enter the class name or enter the class-default keyword.

A class policy is defined for each class group.

Step 5 

set qos-group {group-id}

Example:

Router(config-pmap-c)# set qos-group 1

Sets a QoS group identifier (ID) that can be used to classify packets.

Step 6 

set discard-class value

Example:

Router(config-pmap-c)# set discard-class 1

Marks a packet with a discard-class value.

Step 7 

exit

Example:

Router(config-pmap-c)# exit

Exits policy-map class configuration mode and enters policy-map configuration mode.

Step 8 

exit

Example:

Router(config-pmap)# exit

Exits policy-map configuration mode and enters global configuration mode.

Step 9 

interface type number [name-tag]

Example:

Router(config)# interface POS1/0

Configures the interface type specified and enters interface configuration mode.

Enter interface type.

Step 10 

description string

Example:

Router(config-if)# description IP VPN Decapsulation - Backbone Facing

Adds a description to the interface configuration.

Step 11 

ip directed-broadcast [access-list-number] | [extended access-list-number]

Example:

Router(config-if)# no ip directed-broadcast

Enables the translation of a directed broadcast to physical broadcasts.

This configuration is designed to disable this functionality.

Step 12 

ip address ip-address mask [secondary]

Example:

Router(config-if)# ip address 192.168.234.5 255.255.255.0

Sets a primary or secondary IP address for an interface.

Step 13 

service-policy {input | output} policy-map-name

Example:

Router(config-if)# service-policy input set_qos_disc_from_prec

Specifies the name of the policy map to be attached to the input or output direction of the interface.

Policy maps can be configured on ingress or egress routers. They can also be attached in the input or output direction of an interface. The direction (input or output) and the router (ingress or egress) to which the policy map should be attached varies according your network configuration.

Enter the input keyword followed by the policy map name.

Note For this feature, only the incoming interface configured with the input keyword is supported.

Step 14 

end

Example:

Router(config-if)# end

(Optional) Exits interface configuration mode, and enters privileged EXEC mode.

Proceed to the sections, Verifying the VRF and RiV and Verifying the Multipoint L2TPv3 Tunnel, to verify the configuration of the MPLS-VPNs over IP Tunnels feature.

Configuring MPLS VPN Carrier Supporting Carrier over IP Tunnels

To enable a backbone carrier to share its backbone network, configured for the MPLS VPNs over IP Tunnels feature with a customer carrier, you must perform the following tasks:

1. Configure the PE router in the MPLS VPNs over IP Tunnels backbone-carrier network.

2. Configure the CE router in the customer-carrier network that links to the edge router of the backbone carrier.

This section describes how to perform each task. For more detailed information about the configuration procedure and command syntaxes, refer to the "Configuration Tasks" section in the MPLS VPN—Carrier Supporting Carrier and MPLS VPN—Carrier Supporting Carrier—IPv4 BGP Label Distribution documents.

Prerequisites

The PE routers of the backbone carrier require 128 MB of memory.

The backbone carrier must enable the PE router to check that the packets it receives from the CE router contain only the labels that the PE router advertised to the CE router. This prevents data spoofing, which occurs when a packet from an unrecognized IP address is sent to a router.

A routing protocol is required between the PE and CE routers that connect the backbone carrier to the customer carrier. The routing protocol enables the customer carrier to exchange IGP routing information with the backbone carrier. Use the same routing protocol that the customer carrier uses. RIP, OSPF, eBGP, and static routing are supported as the routing protocol.

To connect the backbone carrier to the customer carrier, one of the following combinations of routing protocols is required on the PE and CE routers that connect the backbone carrier to the customer carrier:

IGP and LDP

eBGP and labels

All PE routers that link the backbone carrier to the customer carrier must run this Cisco IOS software image. Other PE routers, CE routers, and P routers do not need to run this software image, but they must run a version of Cisco IOS software that supports MPLS VPNs.

Every packet that crosses the backbone carrier must be encapsulated, so that the packet includes MPLS labels. To ensure that the packets are encapsulated, you must enter the mpls ip command on each PE router that connects to a CE router.

The following features are not supported in the MPLS VPN—Carrier Supporting Carrier feature:

ATM MPLS

Carrier-supporting-carrier traffic engineering

Carrier-supporting-carrier class of service (CoS)

RSVP aggregation

VPN Multicast between the customer carrier and the backbone carrier network

Configuring the Backbone-Carrier PE Router

SUMMARY STEPS

1. enable

2. configure terminal

3. mpls label protocol ldp

4. mpls ip

5. end

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 

mpls label protocol ldp

Example:

Router(config)# mpls label protocol ldp

Sets the default label distribution protocol for all interfaces to be LDP.

Step 4 

mpls ip

Example:

Router(config)# mpls ip

Enables MPLS on the VRF interface of the PE router in the backbone-carrier network, as configured in Configuring a VRF for an L2TPv3 Tunnel.

Step 5 

end

Example:

Router(config-if)# end

Exits global configuration mode, and enters privileged EXEC mode.

Configuring the Customer-Carrier PE Router

SUMMARY STEPS

1. enable

2. configure terminal

3. mpls label protocol ldp

4. mpls ip

5. end

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 

mpls label protocol ldp

Example:

Router(config)# mpls label protocol ldp

Sets the default label distribution protocol for all interfaces to be LDP.

Step 4 

mpls ip

Example:

Router(config)# mpls ip

Enables MPLS on the VRF interface of the CE router in the customer-carrier network, as configured in Configuring a VRF for an L2TPv3 Tunnel.

Step 5 

end

Example:

Router(config-if)# end

Exits global configuration mode, and enters privileged EXEC mode.

1. Proceed to Verifying the MPLS VPN—Carrier Supporting Carrier Configuration to verify the status of LDP sessions that were configured for the Carrier Supporting Carrier feature between the backbone carrier and customer carrier. The customer-carrier sites should appear as a VPN customer to the backbone carrier.configured for the MPLS-VPNs over IP Tunnels feature.

2. Then proceed to the sections, Verifying the VRF and RiV and Verifying the Multipoint L2TPv3 Tunnel, to verify the configuration of the MPLS-VPNs over IP Tunnels feature.

Verifying the VRF and RiV

Use the following steps to verify the configuration of the VRF and RiV.

SUMMARY STEPS

1. enable

2. show ip bgp vpnv4 vrf vrf-name

3. show ip route vrf vrf-name

4. show ip cef vrf vrf-name

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 bgp vpnv4 {all | rd route-distinguisher | vrf vrf-name} [ip-prefix/length [longer-prefixes] [output-modifiers]] [network-address [mask] [longer-prefixes] [output-modifiers]] [cidr-only] [community] [community-list] [dampened-paths] [filter-list] [flap-statistics] [inconsistent-as] [neighbors] [paths [line]] [peer-group] [quote-regexp] [regexp] [summary] [tags]

Example:

Router# show ip bgp vpnv4 vrf MY_RIV

Displays VPN address information from the BGP table. This command is used to verify that the specified VRF has been received by BGP. The BGP table entry should show that the route-map has worked and that the next hop is showing in the RiV. If the VRF route is not in the BGP VRF, reconfigure the VRF and route distinguisher.

Step 3 

show ip route vrf vrf-name [connected] [protocol [as-number] [tag] [output-modifiers]] [ip-prefix] [list number [output-modifiers]] [profile] [static [output-modifiers]] [summary [output-modifiers]] [supernets-only [output-modifiers]] [traffic-engineering [output-modifiers]]

Example:

Router# show ip route vrf MY_RIV

Displays the IP routing table associated with a VRF instance. The show ip route vrf command is used to verify that the VRF is in the routing table. If the VRF is in the routing table but the PE router still cannot be reached using the ping command, reconfigure the VRF and route distinguisher.

Step 4 

show ip cef vrf vrf-name [ip-prefix [mask [longer-prefixes]] [detail] [output-modifiers]] [interface interface-number] [adjacency] [interface interface-number] [detail] [discard] [drop] [glean] [null] [punt] [output-modifiers]] [detail [output-modifiers]] [non-recursive [detail] [output-modifiers]] [summary [output-modifiers]] [traffic [prefix-length] [output-modifiers]] [unresolved [detail] [output-modifiers]]

Example:

Router# show ip cef vrf MY_RIV

Displays the CEF forwarding table associated with VRF that was configured for the VPN. This command is used to verify that the correct VRF routes are in the CEF table. If the VRF route is not in the CEF table, reconfigure the VRF and route distinguisher.

Verifying the Multipoint L2TPv3 Tunnel

Use the following steps to verify the configuration of the multipoint L2TPv3 tunnel.

SUMMARY STEPS

1. enable

2. show interface interface

3. show l2tun

4. show tunnel endpoint vrf-name

5. show ip bgp ipv4 tunnel [ip-address | summary]

DETAILED STEPS

 
Command or Action
Purpose

Step 1 

enable

Example:

Router> enable

Enables privileged EXEC mode.

Enter your password if prompted.

Step 2 

show interface interface

Example:

Router# show interface Tunnel 1

Displays the information about the specified interface.

This command used to verify that the tunnel interface is correctly configured and functioning properly.

Step 3 

show l2tun

Example:

Router# show l2tun

Displays the state of L2TPv3 tunnels and currently configured sessions.

This command is used to verify tunnel and session information.

Step 4 

show tunnel endpoint interface

Example:

Router# show tunnel endpoint

Displays source and destination information for tunnel endpoints.

This command is used to verify that the tunnel endpoints were created correctly.

Step 5 

show ip bgp ipv4 tunnel [ip-address | summary]

Example:

Router# show ip bgp ipv4 tunnel summary

Displays "tunnel" SAFI specific information.

This command is used to verify the tunnel type, tunnel capabilities, tunnel-specific attributes, and tunnel endpoints.

Verifying the Modular QoS CLI Configuration

To verify that this feature is configured as intended and that either the IP precedence or DSCP value is set as expected, complete the following steps.

SUMMARY STEPS

1. enable

2. show policy-map interface interface-name

or

show policy-map policy-map

3. exit

DETAILED STEPS

 
Command or Action
Purpose

Step 1 

enable

Example:

Router> enable

Enables privileged EXEC mode.

Enter your password if prompted.

Step 2 

show policy-map interface interface-name

Example:

Router# show policy-map interface s4/0

(Optional) Displays the packet statistics of all classes that are configured for all service policies either on the specified interface or subinterface or on a specific PVC on the interface.

Enter the interface name.

 

or

show policy-map policy-map

Example:

Router# show policy-map qos3

(Optional) Displays the configuration of all classes for a specified service policy map or all classes for all existing policy maps.

Enter a policy map name.

Step 3 

exit

Example:

Router# exit

Exits privileged EXEC mode.

Troubleshooting Tips

Use the commands in the "Verifying the Modular QoS CLI Configuration" section to verify that you achieved the intended configuration and that the feature is functioning correctly. If, after using the show commands listed above, you find that the configuration is not correct or the feature is not functioning as expected, perform these operations:

If the configuration is not the one you intended, complete the following procedures:

Use the show running-config command and analyze the output of the command.

If the policy map does not appear in the output of the show running-config command, enable the logging console command. Attach the policy map to the interface again.

Verifying the MPLS VPN—Carrier Supporting Carrier Configuration

To verify the MPLS VPN—Carrier Supporting Carrier feature on interfaces configured for MPLS VPNs over IP Tunnels on PE routers in a backbone carrier network:

1. Follow the procedure in this section to verify the status of LDP sessions between the backbone carrier and customer carrier configured for the Carrier Supporting Carrier feature.

2. Follow the procedures in Verifying the VRF and RiV and Verifying the Multipoint L2TPv3 Tunnel to verify the configuration of the MPLS-VPNs over IP Tunnels feature.

To verify the status of LDP sessions between the backbone carrier and customer carrier configured for the MPLS VPN—Carrier Supporting Carrier feature, complete the following steps. The customer-carrier sites should appear as a VPN customer to the backbone carrier.configured for the MPLS VPNs over IP Tunnels feature.

SUMMARY STEPS

1. enable

2. show mpls ldp discovery vrf vpn-name

or

show mpls ldp discovery all

3. exit

DETAILED STEPS

 
Command or Action
Purpose

Step 1 

enable

Example:

Router> enable

Enables privileged EXEC mode.

Enter your password if prompted.

Step 2 

show mpls ldp discovery vrf vpn-name

Example:

Router# show mpls ldp discovery vrf vpn1

(Optional) Displays the neighbor discovery information for the specified VPN routing/forwarding instance (vpn-name).

Enter the name of the VRF RiV instance created in Configuring a VRF for an L2TPv3 Tunnel for the L2TPv3 tunnel.

 

or

show mpls ldp discovery all

Example:

Router# show mpls ldp discovery all

(Optional) Displays LDP discovery information for all VPNs, including those in the default routing domain.

Step 3 

exit

Example:

Router# exit

Exits privileged EXEC mode.

Configuration Examples for MPLS VPNs over IP Tunnels

Configuring the VRF and RiV—Example

Configuring the Multipoint L2TPv3 Tunnel—Example

Configuring a Route Map for the Layer 3 VPN—Example

Defining Address Space and Configuring BGP—Example

Configuring Tunnel Marking on the Encapsulation Interface—Example

Mapping Tunnel Marking to QoS-group and Discard-Class—Example

Configuring MPLS VPN Carrier Supporting Carrier over IP Tunnels—Examples

Verifying the VRF—Example

Verifying the Multipoint L2TPv3 Tunnel—Examples

Verifying QoS Configuration—Example

Verifying MPLS VPN Carrier Supporting Carrier over IP Tunnels—Example


Note 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.


Configuring the VRF and RiV—Example

The following sample configuration creates and configures the VRF and RiV:

ip vrf vrf-name
 rd 100:110 
 route-target import 100:1000 
 route-target export 100:1000 
 exit 
ip vrf MY_RIV 
 rd 1:1 
 end

Configuring the Multipoint L2TPv3 Tunnel—Example

The following sample configuration creates and configures the L2TPv3 tunnel:

interface tunnel 1
 ip vrf forwarding MY_RIV
 ip-address 172.16.1.3 255.255.255.255
 tunnel source loopback 0
 tunnel mode l3vpn l2tpv3 multipoint
 end

Configuring a Route Map for the Layer 3 VPN—Example

The following sample configuration creates an inbound route map to set the next hop to be resolved within the VRF:

route-map SELECT_UPDATE_FOR_L3VPN permit 10
 set ip next-hop in-vrf MY_RIV
 end

Defining Address Space and Configuring BGP—Example

The following sample configuration defines address space for the VPN and configures BGP:

ip route vrf MY_RIV 0.0.0.0 0.0.0.0 tunnel 1
router bgp 100 
 neighbor 172.16.1.2 remote-as 100
 neighbor 172.16.1.2 update-source Loopback 0
 address-family vpnv4 unicast
 neighbor 172.16.1.2 activate
 neighbor 172.16.1.2 route-map SELECT_UPDATE_FOR_L3VPN in 
 exit-address-family
 address-family ipv4 tunnel
 neighbor 176.16.1.2 activate
 end

Configuring Tunnel Marking on the Encapsulation Interface—Example

The following examples show how to configure QoS to control bandwidth. These examples show how to configure IP precedence or DSCP using individual set actions or by configuring policing actions.

In the following example, a policy map named "set_prec_tun" is created and the IP precedence is configured in the policy map. You could use the set ip dscp tunnel command instead of the set ip precedence tunnel command if you do not use IP precedence in your network.

policy-map set_prec_tun 
 class class-default 
  set ip precedence tunnel 2 
  set ip precedence 2 

In the following example, the IP precedence is configured as a policing action using the police command. Like the previous example, DSCP or IP precedence can be configured.

policy-map policer_prec_tun 
 class class-default 
  police cir 1280000 conform-action set-prec-tunnel-transmit 3 exceed-action drop 

The following example attaches the policy map to the interface. This step is required regardless of which method is used to configure IP precedence or DSCP.

interface POS0/0 
 description IP VPN Encapsulation - Customer Facing
 ip vrf forwarding IP_VPN 
 ip address 192.168.123.4 255.255.255.0
 service-policy input set_prec_tun

Mapping Tunnel Marking to QoS-group and Discard-Class—Example

The following example configures the policy on the decapsulation interface in the input direction. The QoS policy can be constructed based on the precedence or DSCP value in the IP carrier header of the received packet. The MQC policy is configured to match on the IP precedence or DSCP value received in the IP carrier header.

policy-map set_qos_disc_from_prec 
 class match_prec1 
  set qos-group 1 
  set discard-class 1 
 class match_prec2 
  set qos-group 2
  set discard-class 2 
 class match_prec3 
  set qos-group 3 
  set discard-class 3 
 class class-default 
  set discard-class 4 
  set qos-group 4 

The following example attaches the policy map to the interface:

interface POS1/0 
 description IP VPN Decapsulation - Backbone Facing 
 ip address 192.168.234.5 255.255.255.0 
 no ip directed-broadcast 
 ip router isis 
 service-policy input set_qos_disc_from_prec 

Configuring MPLS VPN Carrier Supporting Carrier over IP Tunnels—Examples

Figure 1 shows examples of how to configure the Carrier Supporting Carrier (CsC) feature on the interfaces of supported ISE and Engine 5 line cards in the PE routers of a backbone carrier (configured for the MPLS VPNs over IP Tunnels feature) and on the CE routers in one of the following types of customer carrier network:

Internet service provider (ISP) with IP networks

MPLS VPN customer carrier with MPLS/IP networks

Configuration for an ISP Customer Carrier

The following example shows how to configure the MPLS VPN Carrier Supporting Carrier over IP Tunnels feature for an ISP customer carrier to interconnect IP networks over a backbone MPLS VPNs over IP Tunnels network.

Figure 1 MPLS VPN Carrier Supporting Carrier over IP Tunnels for an ISP Customer Carrier

In this example, the following conditions apply:

The customer carrier exchanges external IPv4 routes directly.

The customer carrier exchanges internal IPv4 routes (and labels) with the backbone carrier.

The backbone carrier exchanges customer carrier internal IPv4 routes as VPNv4 routes.

The backbone carrier exchanges IPv4 tunnel endpoints internally.

For the MPLS VPN Carrier Supporting Carrier over IP Tunnels configuration shown in Figure 1, you must configure the two PE routers (CSC_PE1 and CSC-PE2) in the backbone carrier network and the two CE routers (CSC-CE1 and CSC-CE2) in the customer carrier networks, as described in the following sections.

CSC-CE1 Configuration

hostname csc-ce1

mpls label protocol ldp

interface Loopback0
 ip address 10.100.2.2 255.255.255.255
 no ip directed-broadcast
 no ip route-cache
 no ip mroute-cache

interface Loopback1
 ip address 10.101.2.2 255.255.255.255
 no ip directed-broadcast
 no ip route-cache

interface Loopback2
 ip address 10.102.2.2 255.255.255.255
 no ip directed-broadcast

interface POS2/0
 no ip address
 no ip directed-broadcast
 encapsulation frame-relay
 no keepalive
 tag-switching ip
 crc 32
 clock source internal

interface POS2/0.100 point-to-point
 ip address 192.168.80.4 255.255.255.0
 no ip directed-broadcast
 mpls label protocol ldp
 tag-switching ip
 frame-relay interface-dlci 100   

interface POS2/0.200 point-to-point
 ip address 192.168.80.5 255.255.255.0
 no ip directed-broadcast
 mpls bgp forwarding
 frame-relay interface-dlci 200   

interface POS2/0.300 point-to-point
 ip address 192.168.80.6 255.255.255.0
 no ip directed-broadcast
 mpls label protocol ldp
 tag-switching ip
 frame-relay interface-dlci 300   

interface POS2/0.400 point-to-point
 ip address 192.168.80.11 255.255.255.0
 no ip directed-broadcast
 frame-relay interface-dlci 400   

interface POS6/3
 no ip address
 no ip directed-broadcast
 encapsulation frame-relay
 no keepalive
 crc 32
 clock source internal

interface POS6/3.100 point-to-point
 ip address 192.168.70.4 255.255.255.0
 no ip directed-broadcast
 frame-relay interface-dlci 70   

interface POS6/3.200 point-to-point
 ip address 192.168.70.5 255.255.255.0
 no ip directed-broadcast
 mpls label protocol ldp
 tag-switching ip
 frame-relay interface-dlci 200   

interface POS6/3.300 point-to-point
 ip address 192.168.70.6 255.255.255.0
 no ip directed-broadcast
 frame-relay interface-dlci 300   

router ospf 16
 log-adjacency-changes
 redistribute connected subnets
 network 192.168.70.4.0.0.0.255 area 100
 network 192.168.80.4.0.0.0.255 area 100

router ospf 26
 log-adjacency-changes
 redistribute connected subnets
 redistribute bgp 200 subnets
 network 192.168.70.5.0.0.0.255 area 200
 network 192.168.80.5.0.0.0.255 area 200

router ospf 3
 log-adjacency-changes
 redistribute connected subnets
 network 192.168.70.6.0.0.0.255 area 3
 network 192.168.80.6.0.0.0.255 area 3
 network 10.102.2.2 0.0.0.0 area 3

router bgp 200
 bgp log-neighbor-changes
 neighbor 192.168.80.5 remote-as 100
 neighbor 10.101.1.1 remote-as 200
 neighbor 10.101.1.1 update-source Loopback1
 neighbor 10.201.1.1 remote-as 200
 neighbor 10.201.1.1 update-source Loopback1
 neighbor 10.201.2.2 remote-as 200
 neighbor 10.201.2.2 update-source Loopback1

 address-family ipv4
 redistribute ospf 26
 neighbor 192.168.80.5 activate
 neighbor 192.168.80.5 send-label
 no neighbor 10.101.1.1 activate
 no neighbor 10.201.1.1 activate
 no neighbor 10.201.2.2 activate
 no auto-summary
 no synchronization
 exit-address-family

 address-family vpnv4
 neighbor 10.101.1.1 activate
 neighbor 10.101.1.1 send-community extended
 neighbor 10.201.1.1 activate
 neighbor 10.201.1.1 send-community extended
 neighbor 10.201.2.2 activate
 neighbor 10.201.2.2 send-community extended
 exit-address-family

CSC-PE1 Configuration

hostname csc-pe1

ip vrf forwarding

ip vrf my_riv
 rd 1:1

ip vrf vpn100
 rd 100:100
 route-target export 100:100
 route-target import 100:100

ip vrf vpn200
 rd 200:200
 route-target export 200:200
 route-target import 200:200

ip vrf vpn300
 rd 300:300
 route-target export 300:300
 route-target import 300:300

mpls label protocol ldp

interface Loopback0
 ip address 10.127.80.80 255.255.255.255
 no ip directed-broadcast
 ip router isis 
 no ip route-cache

interface Tunnel100
 bandwidth 10000
 ip vrf forwarding my_riv
 ip address 192.168.1.1 255.255.255.255
 no ip redirects
 no ip directed-broadcast
 tunnel source Loopback0
 tunnel mode l3vpn l2tpv3 multipoint

interface POS4/0
 no ip address
 no ip directed-broadcast
 encapsulation frame-relay
 no keepalive
 mpls label protocol ldp
 tag-switching ip
 crc 32
 clock source internal

interface POS4/0.100 point-to-point
 ip vrf forwarding vpn100
 ip address 192.168.80.4 255.255.255.0
 no ip directed-broadcast
 mpls label protocol ldp
 tag-switching ip
 frame-relay interface-dlci 100   

interface POS4/0.200 point-to-point
 ip vrf forwarding vpn200
 ip address 192.168.80.5 255.255.255.0
 no ip directed-broadcast
 mpls bgp forwarding
 frame-relay interface-dlci 200   

interface POS4/0.300 point-to-point
 ip vrf forwarding vpn300
 ip address 192.168.80.6 255.255.255.0
 no ip directed-broadcast
 mpls label protocol ldp
 tag-switching ip
 frame-relay interface-dlci 300   

interface POS5/0
 ip address 192.168.90.4 255.255.255.0
 no ip directed-broadcast
 ip router isis 
 no keepalive
 crc 32
 clock source internal

router ospf 16 vrf vpn100
 log-adjacency-changes
 redistribute bgp 100 subnets
 network 192.168.80.4.0.0.0.255 area 100

router ospf 3 vrf vpn300
 log-adjacency-changes
 redistribute bgp 100 subnets
 network 192.168.80.6.0.0 0.255 area 3

router isis 
 net 49.0001.0000.0000.000a.00

router bgp 100
 bgp log-neighbor-changes
 neighbor 10.10.10.10 remote-as 100
 neighbor 10.10.10.10 update-source Loopback0
 neighbor 10.20.20.20 remote-as 100
 neighbor 10.20.20.20 update-source Loopback0
 neighbor 10.30.30.30 remote-as 100
 neighbor 10.30.30.30 update-source Loopback0

 address-family ipv4
 no neighbor 10.10.10.10 activate
 no neighbor 10.20.20.20 activate
 no neighbor 10.30.30.30 activate
 no auto-summary
 no synchronization
 exit-address-family

 address-family ipv4 tunnel
 neighbor 10.10.10.10 activate
 neighbor 10.20.20.20 activate
 neighbor 10.30.30.30 activate
 exit-address-family

 address-family vpnv4
 neighbor 10.10.10.10 activate
 neighbor 10.10.10.10 send-community both
 neighbor 10.10.10.10 route-map rmap1 in
 neighbor 10.20.20.20 activate
 neighbor 10.20.20.20 send-community both
 neighbor 10.20.20.20 route-map rmap1 in
 neighbor 10.30.30.30 activate
 neighbor 10.30.30.30 send-community both
 neighbor 10.30.30.30 route-map rmap1 in
 exit-address-family

 address-family ipv4 vrf vpn300
 redistribute connected
 redistribute ospf 3 vrf vpn300
 no auto-summary
 no synchronization
 exit-address-family

 address-family ipv4 vrf vpn200
 neighbor 192.168.80.5 remote-as 200
 neighbor 192.168.80.5 activate
 neighbor 192.168.80.5 as-override
 neighbor 192.168.80.5 send-label
 no auto-summary
 no synchronization
 exit-address-family

 address-family ipv4 vrf vpn100
 redistribute connected
 redistribute ospf 16 vrf vpn100
 no auto-summary
 no synchronization
 exit-address-family

 address-family ipv4 vrf my_riv
 no auto-summary
 no synchronization
 exit-address-family

 address-family ipv4 vrf forwarding
 no auto-summary
 no synchronization
 exit-address-family

ip route vrf my_riv 0.0.0.0 0.0.0.0 Tunnel100

route-map rmap1 permit 10
 set ip next-hop in-vrf my_riv

CSC-CE2 Configuration

hostname csc-ce2

mpls label protocol ldp
no mpls traffic-eng auto-bw timers frequency 0

interface Loopback1
 ip address 10.201.2.2 255.255.255.255
 no ip directed-broadcast
 no ip route-cache
 no ip mroute-cache

interface POS12/0
 ip address 192.168.110.4 255.255.255.0
 no ip directed-broadcast
 no keepalive
 mpls ldp discovery transport-address 11.11.11.11
 mpls label protocol ldp
 tag-switching ip
 crc 32
 clock source internal

router ospf 17
 log-adjacency-changes
 redistribute connected subnets
 network 192.168.110.4.0.0.0.255 area 100

router bgp 200
 bgp log-neighbor-changes
 neighbor 10.101.1.1 remote-as 200
 neighbor 10.101.1.1 update-source Loopback1
 neighbor 10.101.2.2 remote-as 200
 neighbor 10.101.2.2 update-source Loopback1
 neighbor 10.201.1.1 remote-as 200
 neighbor 10.201.1.1 update-source Loopback1

 address-family ipv4
 no neighbor 10.101.1.1 activate
 no neighbor 10.101.2.2 activate
 no neighbor 10.201.1.1 activate
 no auto-summary
 no synchronization
 exit-address-family

 address-family vpnv4
 neighbor 10.101.1.1 activate
 neighbor 10.101.1.1 send-community extended
 neighbor 10.101.2.2 activate
 neighbor 10.101.2.2 send-community extended
 neighbor 10.201.1.1 activate
 neighbor 10.201.1.1 send-community extended
 exit-address-family

ip classless
ip route 192.168.80.8 255.255.255.0 110.8.0.1
ip route 192.168.80.11 255.255.255.0 110.11.0.1 

CSC-PE2 Configuration

hostname csc-pe2

ip vrf forwarding

ip vrf my_riv
 rd 1:1

ip vrf vpn100
 rd 100:100
 route-target export 100:100
 route-target import 100:100

mpls label protocol ldp

interface Loopback0
 ip address 10.127.10.10 255.255.255.255
 no ip directed-broadcast
 ip router isis 

interface Loopback1
 ip vrf forwarding vpn100
 ip address 10.127.12.12 255.255.255.255
 no ip directed-broadcast

interface Tunnel100
 ip vrf forwarding my_riv
 ip address 192.168.3.3 255.255.255.255
 no ip redirects
 no ip directed-broadcast
 tunnel source Loopback0
 tunnel mode l3vpn l2tpv3 multipoint

interface POS6/0
 ip address 192.168.100.4 255.255.255.0
 no ip directed-broadcast
 ip router isis 
 crc 32
 clock source internal

interface POS8/0
 ip vrf forwarding vpn100
 ip address 192.168.110.4 255.255.255.0
 no ip directed-broadcast
 no keepalive
 mpls ldp discovery transport-address 12.12.12.12
 mpls label protocol ldp
 tag-switching ip
 crc 32
 clock source internal

router ospf 17 vrf vpn100
 log-adjacency-changes
 redistribute connected subnets
 redistribute bgp 100 subnets
 network 192.168.110.4.0.0.0.255 area 100

router isis 
 net 49.0001.0000.0000.000c.00

router bgp 100
 no synchronization
 bgp log-neighbor-changes
 neighbor 10.127.80.80 remote-as 100
 neighbor 10.127.80.80 update-source Loopback0
 no auto-summary

 address-family ipv4 tunnel
 neighbor 10.127.80.80 activate
 exit-address-family

 address-family vpnv4
 neighbor 10.127.80.80 activate
 neighbor 10.127.80.80 send-community both
 neighbor 10.127.80.80 route-map rmap1 in
 exit-address-family

 address-family ipv4 vrf vpn400
 redistribute connected
 no auto-summary
 no synchronization
 exit-address-family

 address-family ipv4 vrf vpn100
 redistribute connected
 redistribute ospf 17 vrf vpn100
 no auto-summary
 no synchronization
 exit-address-family

 address-family ipv4 vrf my_riv
 no auto-summary
 no synchronization
 exit-address-family

 address-family ipv4 vrf forwarding
 no auto-summary
 no synchronization
 exit-address-family

ip route vrf my_riv 0.0.0.0 0.0.0.0 Tunnel100

route-map rmap1 permit 10
 set ip next-hop in-vrf my_riv

Configuration for an MPLS VPN Customer Carrier

Figure 2 shows how to configure the MPLS VPN Carrier Supporting Carrier over IP Tunnels feature for an MPLS VPN customer carrier to interconnect MPLS/IP networks over a backbone MPLS VPNs over IP Tunnels network.

Figure 2 MPLS VPN Carrier Supporting Carrier over IP Tunnels for an MPLS VPN Customer Carrier

In this example, the following conditions apply:

The customer carrier exchanges external VPNv4 routes directly.

The customer carrier exchanges internal IPv4 routes (and labels) with the backbone carrier.

The backbone carrier exchanges customer carrier internal IPv4 routes as VPNv4 routes.

The backbone carrier exchanges IPv4 tunnel endpoints internally.

For the MPLS VPN Carrier Supporting Carrier over IP Tunnels configuration shown in Figure 2, you must configure the two PE routers (CSC-PE1 and CSC-PE2) in the backbone carrier network and the two CE routers (CSC-CE1 and CSC-CE2) in the customer carrier networks, as described in the following sections.

CSC-CE1 Configuration

hostname csc-ce1

mpls label protocol ldp

interface Loopback0
 ip address 10.127.100.2 255.255.255.255
 no ip directed-broadcast
 no ip route-cache
 no ip mroute-cache

interface Loopback1
 ip address 10.127.101.2 255.255.255.255
 no ip directed-broadcast
 no ip route-cache

interface Loopback2
 ip address 10.127.102.2 255.255.255.255
 no ip directed-broadcast

interface POS2/0
 no ip address
 no ip directed-broadcast
 encapsulation frame-relay
 no keepalive
 tag-switching ip
 crc 32
 clock source internal

interface POS2/0.100 point-to-point
 ip address 192.168.80.4 255.255.255.0
 no ip directed-broadcast
 mpls label protocol ldp
 tag-switching ip
 frame-relay interface-dlci 100   

interface POS2/0.200 point-to-point
 ip address 192.168.80.5 255.255.255.0
 no ip directed-broadcast
 mpls bgp forwarding
 frame-relay interface-dlci 200   

interface POS2/0.300 point-to-point
 ip address 192.168.80.6 255.255.255.0
 no ip directed-broadcast
 mpls label protocol ldp
 tag-switching ip
 frame-relay interface-dlci 300   

interface POS2/0.400 point-to-point
 ip address 192.168.80.11 255.255.255.0
 no ip directed-broadcast
 frame-relay interface-dlci 400   

interface POS6/3
 no ip address
 no ip directed-broadcast
 encapsulation frame-relay
 no keepalive
 crc 32
 clock source internal

interface POS6/3.100 point-to-point
 ip address 192.168.70.4 255.255.255.0
 no ip directed-broadcast
 frame-relay interface-dlci 70   

interface POS6/3.200 point-to-point
 ip address 192.168.70.5 255.255.255.0
 no ip directed-broadcast
 mpls label protocol ldp
 tag-switching ip
 frame-relay interface-dlci 200   

interface POS6/3.300 point-to-point
 ip address 192.168.70.6 255.255.255.0
 no ip directed-broadcast
 frame-relay interface-dlci 300   

router ospf 16
 log-adjacency-changes
 redistribute connected subnets
 network 192.168.70.4.0.0.0.255 area 100
 network 192.168.80.4.0.0 0.255 area 100

router ospf 26
 log-adjacency-changes
 redistribute connected subnets
 redistribute bgp 200 subnets
 network 192.168.70.5.0.0.0.255 area 200
 network 192.168.80.5.0.0.0.255 area 200

router ospf 3
 log-adjacency-changes
 redistribute connected subnets
 network 192.168.70.6.0.0.0.255 area 3
 network 192.168.80.6.0.0.0.255 area 3
 network 10.102.2.2 0.0.0.0 area 3

router bgp 200
 bgp log-neighbor-changes
 neighbor 192.168.80.5.remote-as 100
 neighbor 10.101.1.1 remote-as 200
 neighbor 10.101.1.1 update-source Loopback1
 neighbor 10.201.1.1 remote-as 200
 neighbor 10.201.1.1 update-source Loopback1
 neighbor 10.201.2.2 remote-as 200
 neighbor 10.201.2.2 update-source Loopback1

 address-family ipv4
 redistribute ospf 26
 neighbor 192.168.80.5.activate
 neighbor 192.168.80.5 send-label
 no neighbor 10.101.1.1 activate
 no neighbor 10.201.1.1 activate
 no neighbor 10.201.2.2 activate
 no auto-summary
 no synchronization
 exit-address-family

 address-family vpnv4
 neighbor 10.101.1.1 activate
 neighbor 10.101.1.1 send-community extended
 neighbor 10.201.1.1 activate
 neighbor 10.201.1.1 send-community extended
 neighbor 10.201.2.2 activate
 neighbor 10.201.2.2 send-community extended
 exit-address-family

CSC-PE1 Configuration

hostname csc-pe1

ip vrf forwarding

ip vrf my_riv
 rd 1:1

ip vrf vpn100
 rd 100:100
 route-target export 100:100
 route-target import 100:100

ip vrf vpn200
 rd 200:200
 route-target export 200:200
 route-target import 200:200

ip vrf vpn300
 rd 300:300
 route-target export 300:300
 route-target import 300:300

mpls label protocol ldp

interface Loopback0
 ip address 10.127.80.80 255.255.255.255
 no ip directed-broadcast
 ip router isis 
 no ip route-cache

interface Tunnel100
 bandwidth 10000
 ip vrf forwarding my_riv
 ip address 192.168.1.1 255.255.255.255
 no ip redirects
 no ip directed-broadcast
 tunnel source Loopback0
 tunnel mode l3vpn l2tpv3 multipoint

interface POS4/0
 no ip address
 no ip directed-broadcast
 encapsulation frame-relay
 no keepalive
 mpls label protocol ldp
 tag-switching ip
 crc 32
 clock source internal

interface POS4/0.100 point-to-point
 ip vrf forwarding vpn100
 ip address 192.168.80.4 255.255.255.0
 no ip directed-broadcast
 mpls label protocol ldp
 tag-switching ip
 frame-relay interface-dlci 100   

interface POS4/0.200 point-to-point
 ip vrf forwarding vpn200
 ip address 192.168.80.5 255.255.255.0
 no ip directed-broadcast
 mpls bgp forwarding
 frame-relay interface-dlci 200   

interface POS4/0.300 point-to-point
 ip vrf forwarding vpn300
 ip address 192.168.80.6 255.255.255.0
 no ip directed-broadcast
 mpls label protocol ldp
 tag-switching ip
 frame-relay interface-dlci 300   

interface POS5/0
 ip address 192.168.90.4 255.255.255.0
 no ip directed-broadcast
 ip router isis 
 no keepalive
 crc 32
 clock source internal

router ospf 16 vrf vpn100
 log-adjacency-changes
 redistribute bgp 100 subnets
 network 192.168.80.4.0.0.0.255 area 100

router ospf 3 vrf vpn300
 log-adjacency-changes
 redistribute bgp 100 subnets
 network 192.168.80.6.0.0.0.255 area 3

router isis 
 net 49.0001.0000.0000.000a.00

router bgp 100
 bgp log-neighbor-changes
 neighbor 10.10.10.10 remote-as 100
 neighbor 10.10.10.10 update-source Loopback0
 neighbor 10.20.20.20 remote-as 100
 neighbor 10.20.20.20 update-source Loopback0
 neighbor 10.30.30.30 remote-as 100
 neighbor 10.30.30.30 update-source Loopback0

 address-family ipv4
 no neighbor 10.10.10.10 activate
 no neighbor 10.20.20.20 activate
 no neighbor 10.30.30.30 activate
 no auto-summary
 no synchronization
 exit-address-family

 address-family ipv4 tunnel
 neighbor 10.10.10.10 activate
 neighbor 10.20.20.20 activate
 neighbor 10.30.30.30 activate
 exit-address-family

 address-family vpnv4
 neighbor 10.10.10.10 activate
 neighbor 10.10.10.10 send-community both
 neighbor 10.10.10.10 route-map rmap1 in
 neighbor 10.20.20.20 activate
 neighbor 10.20.20.20 send-community both
 neighbor 10.20.20.20 route-map rmap1 in
 neighbor 10.30.30.30 activate
 neighbor 10.30.30.30 send-community both
 neighbor 10.30.30.30 route-map rmap1 in
 exit-address-family

 address-family ipv4 vrf vpn300
 redistribute connected
 redistribute ospf 3 vrf vpn300
 no auto-summary
 no synchronization
 exit-address-family

 address-family ipv4 vrf vpn200
 neighbor 192.168.80.5.remote-as 200
 neighbor 192.168.80.5 activate
 neighbor 192.168.80.5 as-override
 neighbor 192.168.80.5 send-label
 no auto-summary
 no synchronization
 exit-address-family

 address-family ipv4 vrf vpn100
 redistribute connected
 redistribute ospf 16 vrf vpn100
 no auto-summary
 no synchronization
 exit-address-family

 address-family ipv4 vrf my_riv
 no auto-summary
 no synchronization
 exit-address-family

 address-family ipv4 vrf forwarding
 no auto-summary
 no synchronization
 exit-address-family

ip route vrf my_riv 0.0.0.0 0.0.0.0 Tunnel100

route-map rmap1 permit 10
 set ip next-hop in-vrf my_riv

CSC-CE2 Configuration

hostname csc-ce2

interface Loopback0
 ip address 10.127.200.2 255.255.255.255
 no ip directed-broadcast
 no ip route-cache
 no ip mroute-cache

interface Loopback1
 ip address 10.127.201.2 255.255.255.255
 no ip directed-broadcast
 no ip route-cache
 no ip mroute-cache

interface Loopback2
 ip address 10.127.202.2 255.255.255.255
 no ip directed-broadcast

interface Loopback3
 ip address 10.127.203.2 255.255.255.255
 no ip directed-broadcast

interface Loopback4
 ip address 10.127.204.2 255.255.255.255
 no ip directed-broadcast

interface Loopback5
 ip address 10.127.11.11 255.255.255.255
 no ip directed-broadcast

interface POS2/0
 ip address 192.168.110.5 255.255.255.0
 no ip directed-broadcast
 no keepalive
 mpls bgp forwarding
 tag-switching ip
 crc 32
 clock source internal

router ospf 27
 log-adjacency-changes
 redistribute connected subnets
 redistribute bgp 200 subnets
 network 192.168.110.5.0.0.0.255 area 200
 network 192.168.120.5.0.0.0.255 area 200
 network 10.201.2.2 0.0.0.0 area 200

router bgp 200
 bgp log-neighbor-changes
 neighbor 10.101.1.1 remote-as 200
 neighbor 10.101.1.1 update-source Loopback1
 neighbor 10.101.2.2 remote-as 200
 neighbor 10.101.2.2 update-source Loopback1
 neighbor 192.168.110.5 remote-as 100
 neighbor 192.168.110.7 remote-as 100
 neighbor 10.201.1.1 remote-as 200
 neighbor 10.201.1.1 update-source Loopback1

 address-family ipv4
 redistribute eigrp 27
 redistribute ospf 27
 no neighbor 10.101.1.1 activate
 no neighbor 10.101.2.2 activate
 neighbor 192.168.110.5 activate
 neighbor 192.168.110.5 send-label
 neighbor 192.168.110.7 activate
 neighbor 192.168.110.7 send-label
 no neighbor 10.201.1.1 activate
 no auto-summary
 no synchronization
 exit-address-family

 address-family vpnv4
 neighbor 10.101.1.1 activate
 neighbor 10.101.1.1 send-community extended
 neighbor 10.101.2.2 activate
 neighbor 10.101.2.2 send-community extended
 neighbor 10.201.1.1 activate
 neighbor 10.201.1.1 send-community extended
 exit-address-family

 address-family ipv4 vrf vpn201
 redistribute connected
 no auto-summary
 no synchronization
 exit-address-family

ip classless
ip route 192.168.80.8 255.255.255.0 110.8.0.1
ip route 192.168.80.11 255.255.255.0 110.11.0.1 

CSC-PE2 Configuration

hostname csc-pe2-2

ip vrf forwarding

ip vrf my_riv
 rd 1:1

ip vrf vpn200
 rd 200:200
 route-target export 200:200
 route-target import 200:200

interface Loopback0
 ip address 10.127.20.20 255.255.255.255
 no ip directed-broadcast
 ip router isis 
 no ip route-cache
 no ip mroute-cache

interface Tunnel100
 bandwidth 10000
 ip vrf forwarding my_riv
 ip address 192.168.5.5 255.255.255.255
 no ip redirects
 no ip directed-broadcast
 tunnel source Loopback0
 tunnel mode l3vpn l2tpv3 multipoint

interface POS3/0
 ip vrf forwarding vpn200
 ip address 192.168.110.5 255.255.255.0
 no ip directed-broadcast
 no keepalive
 mpls bgp forwarding
 crc 32
 clock source internal

interface POS6/0
 ip address 192.168.100.5 255.255.255.0
 no ip directed-broadcast
 ip router isis 
 crc 32
 clock source internal

router isis 
 net 49.0001.0000.0000.000d.00

router bgp 100
 bgp log-neighbor-changes
 neighbor 10.127.80.80 remote-as 100
 neighbor 10.127.80.80 update-source Loopback0

 address-family ipv4
 no neighbor 10.127.80.80 activate
 no auto-summary
 no synchronization
 exit-address-family

 address-family ipv4 tunnel
 neighbor 10.127.80.80 activate
 exit-address-family

 address-family vpnv4
 neighbor 10.127.80.80 activate
 neighbor 10.127.80.80 send-community both
 neighbor 10.127.80.80 route-map rmap1 in
 exit-address-family

 address-family ipv4 vrf vpn400
 redistribute connected
 no auto-summary
 no synchronization
 exit-address-family

 address-family ipv4 vrf vpn200
 neighbor 192.168.110.5 remote-as 200
 neighbor 192.168.110.5 activate
 neighbor 192.168.110.5 as-override
 neighbor 192.168.110.5 send-label
 neighbor 192.168.110.7 remote-as 200
 neighbor 192.168.110.7 activate
 neighbor 192.168.110.7 as-override
 neighbor 192.168.110.7 send-label
 no auto-summary
 no synchronization
 exit-address-family

 address-family ipv4 vrf my_riv
 no auto-summary
 no synchronization
 exit-address-family

 address-family ipv4 vrf forwarding
 no auto-summary
 no synchronization
 exit-address-family

ip route vrf my_riv 0.0.0.0 0.0.0.0 Tunnel100 

Verifying the VRF—Example

Use the show ip bgp vpnv4, show ip route vrf, and show ip cef vrf commands to verify that VRF and RiV are configured correctly propagating to the appropriate routing and forwarding tables.

Verify that the specified VRF prefix has been received by BGP. The BGP table entry should show that the route-map has worked and that the next hop is showing in the RiV. Use the show ip bgp vpnv4 command as shown in this example:

Router# show ip bgp vpnv4 vrf vrf-name 10.10.10.4
BGP routing table entry for 100:1:10.10.10.4/24, version 12
Paths: (1 available, best #1)
  Not advertised to any peer
  Local
    172.16.1.2 in "vrf-name" from 172.16.1.2 (172.16.1.2)
      Origin incomplete, metric 0, localpref 100, valid, internal, best
      Extended Community: RT:100:1

Use the show ip route vrf command to confirm that the same information has been propagated to the routing table:

Router# show ip route vrf vrf-name 10.10.10.4 
Routing entry for 10.10.10.4/24
  Known via "bgp 100", distance 200, metric 0, type internal
  Last update from 172.16.1.2 00:23:07 ago
  Routing Descriptor Blocks:
  * 172.16.1.2 (vrf-name), from 172.16.1.2, 00:23:07 ago
      Route metric is 0, traffic share count is 1

AS Hops 0

Use the show ip cef vrf command to verify that the same information has been propagated to the CEF forwarding table:

Router# show ip cef vrf vrf-name
Prefix              Next Hop             Interface
0.0.0.0/0           attached             Tunnel1
0.0.0.0/32          receive
10.10.10.4/32       10.10.10.4           Tunnel1
172.16.1.2/32       receive
224.0.0.0/4         drop
224.0.0.0/24        receive
255.255.255.255/32  receive
Router# show ip cef vrf CUSTOMER_A
Prefix              Next Hop             Interface
0.0.0.0/0           drop                 Null0 (default route handler entry)
0.0.0.0/32          receive
192.168.0.0/8       10.10.10.4           Tunnel1
10.0.4.0/24         10.10.10.4           Tunnel1
10.0.6.0/24         attached             Serial2/0
10.0.6.0/32         receive
10.0.6.1/32         receive
10.0.6.255/32       receive
224.0.0.0/4         drop
224.0.0.0/24        receive
255.255.255.255/32  receive

Verifying the Multipoint L2TPv3 Tunnel—Examples

Use the show interface, show l2tun, and show tunnel endpoint commands to verify the configuration of the, tunnel interface, L2TPv3 tunnel and tunnel endpoints.

Use the show interface command, as show in the display, to verify that the tunnel interface is up and configured correctly:

Router# show interface Tunnel 1
Tunnel1 is up, line protocol is up 
  Hardware is Tunnel
  Internet address is 172.16.1.2/32
  MTU 1514 bytes, BW 9 Kbit, DLY 500000 usec, rely 255/255, load 1/255
  Encapsulation TUNNEL, loopback not set
  Keepalive not set
  Tunnel source 10.10.10.6 (Loopback0)
  Tunnel protocol/transport Multi-L2TPv3 (L3VPN), sequencing disabled
  Transporting l3vpn traffic to routes recursing through "MY_RIV"
  Key disabled
  Checksumming of packets disabled,  fast tunneling enabled
  Last input never, output never, output hang never
  Last clearing of "show interface" counters never
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
  Queueing strategy: fifo
  Output queue: 0/0 (size/max)
  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
     0 packets input, 0 bytes, 0 no buffer
     Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
     0 packets output, 0 bytes, 0 underruns
     0 output errors, 0 collisions, 0 interface resets
     0 output buffer failures, 0 output buffers swapped out

Use the show l2tun command, as shown in the display, to verify tunnel and session information:

Router# show l2tun
 Tunnel and Session Information Total tunnels 0 sessions 1

L3VPN Session Information Total sessions 1

LocID      Cookie
1025       0xC0DEE550DEADBEEF

Use the show tunnel endpoint command, as shown in the display to verify that the tunnel endpoints were created correctly:

Router# show tunnel endpoint
 Tunnel1 running in Multi-L2TPv3 (L3VPN) mode
  RFC2547/L3VPN Tunnel endpoint discovery is active on Tu1
  Transporting l3vpn traffic to all routes recursing through "MY_RIV"
 Endpoint 10.10.10.4 via destination 10.10.10.4

Use the show ip bgp ipv4 tunnel command, as shown in the display to verify tunnel specific information configured under the "tunnel" SAFI:

Router# show ip bgp ipv4 tunnel
BGP table version is 3, local router ID is 10.3.3.3
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
              r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete
   Network          Next Hop            Metric LocPrf Weight Path
*> 10.3.3.3/32       0.0.0.0                 0         32768 ?
*>i10.5.5.5/32       10.5.5.5                0    100      0 ?
ssacount=1, type L2TP, len 16
        pref 0,flags 0,cookielen 8,ss_id 402,cookie_high D0338947,cookie_low 69DCF79E
ssacount=1, type L2TP, len 16
        pref 0,flags 0,cookielen 8,ss_id 401,cookie_high 6FB30F92,cookie_low A7E61105

Verifying QoS Configuration—Example

This section contains sample output from the show policy-map interface command and the show policy-map command. The output from these commands can be used to verify and monitor the feature configuration in your network.

The following is sample output from the show policy-map interface command. In this sample output, the character string "set precedence tunnel 6" indicates that the tunnel marking has been configured to set the IP precedence in the header of tunneled packets.

Router# show policy-map interface

POS0/0.1 

  Service-policy input: tunnel (1196)

    Class-map: frde (match-any) (1197/18)
      0 packets, 0 bytes
      5 minute offered rate 0 bps, drop rate 0 bps
      Match: fr-de  (1198)
      Set Policy:
        set precedence tunnel 6

    Class-map: class-default (match-any) (1200/0)
      0 packets, 0 bytes
      5 minute offered rate 0 bps, drop rate 0 bps
      Match: any  (1201)
      Set Policy:
        set precedence tunnel 3

The following is sample output from the show policy-map command. In this sample output, the character string "ip precedence tunnel 4" indicates that the tunnel marking on L2TPv3 feature has been configured to set the IP precedence in the header of an L2TPv3 tunneled packet.

Router# show policy-map

Policy Map TUNNEL_MARKING
    Class MATCH_FRDE

set ip precedence tunnel 4

Verifying MPLS VPN Carrier Supporting Carrier over IP Tunnels—Example

This section shows how to use the show mpls ldp discovery command to display the status of the label distribution protocol (LDP) sessions between a PE router in the backbone-carrier (MPLS VPNs over IP Tunnels) network and the CE router in a customer carrier network.

The following example shows the LDP sessions in VRF Customer A of the PE router of the backbone carrier.

Router# show mpls ldp discovery vrf customer_a

Local LDP Identifier:
	139.0.0.0:0
Discovery Sources:
	Interfaces:
		Ethernet1/0 (ldp): xmit/recv
			LDP Id: 55.0.0.1:0
		POS6/0 (ldp): xmit

The next example shows how to display all LDP sessions that are active on the router.

Router# show mpls ldp discovery all
Local LDP Identifier:
	141.141.141.141:0
Discovery Sources:
	Interfaces:
		Ethernet1/5 (ldp): xmit/recv
			LDP Id: 5.5.5.5:0
VRF vpn1: Local LDP Identifier:
	139.0.0.1:0
Discovery Sources:
	Interfaces:
		Ethernet1/0 (ldp): xmit/recv
			LDP Id: 55.0.0.1:0
		POS6/0 (ldp): xmit	Local LDP Identifier:

The Local LDP Identifier field shows the LDP identifier for the local label switching router for this session. The Interfaces field displays the interfaces configured for the Carrier Supporting Carrier feature that are performing LDP discovery activity:

xmit indicates that the interface is transmitting LDP discovery hello packets.

recv indicates that the interface is receiving LDP discovery hello packets.

Additional References

For additional information related to this feature, refer to the following references:

Related Documents

Related Topic
Document Title

CEF switching

Cisco IOS Switching Services Configuration Guide, Release 12.3

QoS—Tunnel Marking

QoS: Tunnel Marking for L2TPv3 Tunnels

VPN configuration

Cisco IOS Dial Services Configuration Guide, Release 12.3 and Cisco IOS Switching Services Configuration Guide, Release 12.3

VPN Routing and Forwarding (VRF) instances

Cisco IOS Switching Services Configuration Guide, Release 12.3

Globally configuring the Label Distribution Protocol (LDP) on every interface associated with a specified Interior Gateway Protocol (IGP) instance

MPLS LDP Autoconfiguration

Configuring PE routers in an MPLS VPN-based service provider to allow other service providers to use a segment of its backbone network:

Using LDP to carry the labels and IGP to carry the routes between PE and CE routers.

Using the Border Gateway Protocol (BGP) to transport routes and MPLS labels between the PE routers and CE routers using multiple paths.

MPLS VPN—Carrier Supporting Carrier

MPLS VPN—Carrier Supporting Carrier—IPv4 BGP Label Distribution


Standards

Standard
Title

IPv4-Tunnel SAFI

IPv4-Tunnel SAFI

http://www.ietf.org/internet-drafts/draft-nalawade-kapoor-tunnel-safi-02.txt


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 obtain lists of supported MIBs by platform and Cisco IOS release, and to download MIB modules, go to the Cisco MIB website on Cisco.com at the following URL:

http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml


RFCs

RFCs
Title

RFC 2547

BGP/MPLS VPNs


Technical Assistance

Description
Link

Technical Assistance Center (TAC) home page, containing 30,000 pages of searchable technical content, including links to products, technologies, solutions, technical tips, and tools. Registered Cisco.com users can log in from this page to access even more content.

http://www.cisco.com/public/support/tac/home.shtml


Command Reference

This section documents modified commands.

address-family ipv4—BGP

clear ip bgp

clear tunnel l3vpn l2tpv3

show ip bgp ipv4

address-family ipv4—BGP

To enter address family configuration mode to configure an IPv4 routing session under a BGP routing process, use the address-family ipv4 command in router configuration mode. To disable an address family specific IPv4 routing session, use the no form of this command.

address-family ipv4 [multicast | unicast | vrf vrf-name | tunnel]

no address-family ipv4 [multicast | unicast | vrf vrf-name | tunnel]

Syntax Description

multicast

(Optional) Specifies an IPv4 multicast address prefix routing session.

unicast

(Optional) Specifies an IPv4 unicast address prefix routing session.

vrf vrf-name

(Optional) Specifies the name of the virtual routing and forwarding (VRF) instance to associate with an IPv4 routing session and subsequent address family configuration mode commands.

tunnel

(Optional) Specifies a IPv4 routing session for multipoint tunnelling.


Defaults

IP Version 4 address prefixes are not enabled. Unicast address prefixes are the default when IP Version 4 address prefixes are configured.

Command Modes

Router configuration

Command History

Release
Modification

12.0(5)T

This command was introduced. The address-family ipv4 command replaces the match nlri and set nlri commands.

12.0(28)S

The tunnel keyword was integrated in Cisco IOS Release 12.0(28)S.

12.0(30)S

Support for the Cisco 12000 series Internet router was added.


Usage Guidelines

The address-family ipv4 command places the router in an address family configuration mode, from which you can configure address family and subaddress family specific routing sessions that use standard IP Version 4 address prefixes. To leave an address family configuration mode and return to router configuration mode, type exit.

Routing information for address family IP Version 4 is advertised by default when you configure a BGP routing session using the neighbor remote-as command unless you enter the no bgp default ipv4-unicast command.

The tunnel keyword is used to enable the tunnel subaddress family identifier (SAFI) under the IPv4 address family identifier. This SAFI is used to advertise the tunnel endpoints and the SAFI specific attributes (which contain the tunnel type and tunnel capabilities). Redistribution of tunnel endpoints into the BGP IPv4 tunnel SAFI table occurs automatically when the tunnel address-family is configured. However, peers need to be activated under the tunnel address-family before the sessions can exchange tunnel information.

Examples

The following example places the router in tunnel address family configuration mode:

Router(config)# router bgp 100
Router(config-router)# address-family ipv4 tunnel
Router(config-router-af)#

The following example places the router in IPv4 address family configuration mode:

Router(config)# router bgp 100
Router(config-router)# address-family ipv4
Router(config-router-af)#

The following example places the router in IPv4 multicast address family configuration mode:

Router(config)# router bgp 100
Router(config-router)# address-family ipv4 multicast
Router(config-router-af)#

The following example places the router in IPv4 unicast address family configuration mode:

Router(config)# router bgp 100
Router(config-router)# address-family ipv4 unicast
Router(config-router-af)#

The following example places the router in address family configuration mode and specifies cisco as the name of the VRF instance to associate with subsequent IP Version 4 address family configuration mode commands:

Router(config)# router bgp 100
Router(config-router)# address-family ipv4 vrf cisco
Router(config-router-af)#

Note Use this form of the command, which specifies a VRF, only to configure routing exchanges between provider edge (PE) and customer edge (CE) devices.


Related Commands

Command
Description

address-family vpnv4

Places the router in address family configuration mode for configuring routing sessions such as BGP, RIP, or static routing sessions that use standard VPN Version 4 address prefixes.

neighbor activate

Enables the exchange of information with a BGP neighboring router.


clear ip bgp

To reset a BGP connection using BGP soft reconfiguration, use the clear ip bgp command in privileged EXEC mode.

clear ip bgp {* | neighbor-address | peer-group peer-group-name} [ipv4 tunnel] [soft [in | out]]

Syntax Description

*

Specifies that all current BGP sessions will be reset.

neighbor-address

Specifies that only the identified BGP neighbor will be reset.

peer-group peer-group-name

Specifies that only the specified BGP peer group will be reset.

ipv4 tunnel

(Optional) Specifies that only the "tunnel" SAFI IPv4 session will be reset.

soft

(Optional) Soft reset. Does not reset the session.

in | out

(Optional) Triggers inbound or outbound soft reconfiguration. If the in or out option is not specified, both inbound and outbound soft reset is triggered.


Defaults

No reset is initiated.

Command Modes

Privileged EXEC

Command History

Release
Modification

10.0

This command was introduced.

12.0(6)T

12.0(2)S

The dynamic inbound soft reset capability was added.


Usage Guidelines

You can reset inbound routing table updates dynamically or by generating new updates using stored update information. Using stored update information required additional memory for storing the updates.

To reset inbound routing table updates dynamically, all BGP routers must support the route refresh capability. To determine whether a BGP router supports this capability, use the show ip bgp neighbors command. If a router supports the route refresh capability, the following message is displayed:

Received route refresh capability from peer.

If all BGP routers support the route refresh capability, use the clear ip bgp {* | address | peer-group-name} in command. You need not use the soft keyword, because soft reset is automatically assumed when the route refresh capability is supported.

To generate new inbound updates from stored update information (rather than dynamically) without resetting the BGP session, you must preconfigure the local BGP router using the neighbor soft-reconfiguration inbound command. This preconfiguration causes the software to store all received updates without modification regardless of whether an update is accepted by the inbound policy. Storing updates is memory intensive and should be avoided if possible.

Outbound BGP soft configuration has no memory overhead and does not require any preconfiguration. You can trigger an outbound reconfiguration on the other side of the BGP session to make the new inbound policy take effect.

Use this command whenever any of the following changes occur:

Additions or changes to the BGP-related access lists

Changes to BGP-related weights

Changes to BGP-related distribution lists

Changes to BGP-related route maps

Examples

The following example clears the inbound session with the neighbor 10.108.1.1 without resetting the session:

Router# clear ip bgp 10.108.1.1 soft in

The following example clears the outbound session with the peer group named corp without resetting the session:

Router# clear ip bgp peer-group corp soft out

Related Commands

Command
Description

neighbor soft-reconfiguration

Configures the Cisco IOS software to start storing updates.

show ip bgp

Displays entries in the BGP routing table.


clear tunnel l3vpn l2tpv3

To reset a Layer 3 VPN session over a L2TPv3 tunnel, use the clear tunnel l3vpn l2tpv3 command in privileged EXEC mode.

clear tunnel l3vpn l2tpv3 [hold-time]

Syntax Description

hold-time

(optional) Configures the amount of time that the existing tunnel session will remain valid, while the new session is propagated to peers. The range of the hold-time argument is from 1 to 59 seconds. The default value is 15 seconds.


Defaults

No reset is initiated.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.0(28)S

This command was integrated in Cisco IOS Release 12.0(28)S.

12.0(30)S

Support for the Cisco 12000 series Internet router was added.


Usage Guidelines

This command is used to generate and distribute a new L2TPv3 session for a Layer 3 VPN. This command is issued on the PE router. The hold-time argument is used to configure the amount of time that the existing session will remain valid, while the new session is propagated to peers. The default value for the hold-time argument is 15 seconds. This should be enough time for most networks. However, this value can be increased if it takes longer for the new session to propagate to all other PE routers.

Examples

The following example resets the existing L2TPv3 session for a Layer 3 VPN and generates a new session:

Router# clear tunnel l3vpn l2tpv3

show ip bgp ipv4

To display entries in the IP version 4 (IPv4) Border Gateway Protocol (BGP) routing table, use the show ip bgp ipv4 command in EXEC mode.

show ip bgp ipv4 {multicast | unicast | tunnel [ip-address | summary]}

Syntax Description

multicast

Displays entries for multicast routes.

unicast

Displays entries for unicast routes.

tunnel

Displays entries configured under the "tunnel" SAFI.

ip-address

Displays tunnel specific information for the specified IP address.

summary

Displays a summary of all routing information configured under the "tunnel" SAFI.


Command Modes

EXEC

Command History

Release
Modification

12.0(5)T

This command was introduced.


Examples

The following is sample output from the show ip bgp ipv4 unicast command:

Router# show ip bgp ipv4 unicast
 BGP table version is 4, local router ID is 10.0.40.1
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal
Origin codes: i - IGP, e - EGP, ? - incomplete

   Network          Next Hop            Metric LocPrf Weight Path
*> 10.10.10.0/24   172.16.10.1              0            0  300 i
*> 10.10.20.0/24   172.16.10.1              0            0  300 i
*  10.20.10.0/24   172.16.10.1              0            0  300 i

The following is sample output from the show ip bgp ipv4 multicast command:

Router# show ip bgp ipv4 multicast
 BGP table version is 4, local router ID is 10.0.40.1
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal
Origin codes: i - IGP, e - EGP, ? - incomplete

   Network          Next Hop            Metric LocPrf Weight Path
*> 10.10.10.0/24   172.16.10.1              0            0  300 i
*> 10.10.20.0/24   172.16.10.1              0            0  300 i
*  10.20.10.0/24   172.16.10.1              0            0  300 i

The following is sample output from the show ip bgp ipv4 tunnel command:

Router# show ip bgp ipv4 tunnel
BGP table version is 3, local router ID is 10.3.3.3
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
              r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete
   Network          Next Hop            Metric	LocPrf													Weight		Path
*> 10.3.3.3/32       0.0.0.0 											0    	 		32768 		?
*>i10.5.5.5/32       10.5.5.5 											0    100			0 		?
ssacount=1, type L2TP, len 16
        pref 0,flags 0,cookielen 8,ss_id 402,cookie_high D0338947,cookie_low 69DCF79E
ssacount=1, type L2TP, len 16
        pref 0,flags 0,cookielen 8,ss_id 401,cookie_high 6FB30F92,cookie_low A7E61105

The following is sample output from the show ip bgp ipv4 summary command:

Router# show ip bgp ipv4 tunnel summary
BGP router identifier 10.3.3.3, local AS number 1
BGP table version is 3, main routing table version 3
..
2 BGP SAFI-Specific-Attr entries using 80 bytes of memory
..
Neighbor        V    AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
10.5.5.5        4     1     422     413        3    0    0 05:28:23        1

The following is sample output from the show ip bgp tunnel command when a single IP address is specified:

Router# show ip bgp ip tunnel 10.5.5.5
BGP routing table entry for 10.5.5.5/32, version 2
Paths: (1 available, best #1, table IPv4-Tunnel-BGP-Table)
  Not advertised to any peer
  Local
    10.5.5.5 (metric 30) from 10.5.5.5 (10.5.5.5)
      Origin incomplete, metric 0, localpref 100, valid, internal, best
      SAFI Specific Attribute: ssacount=1, type L2TP, len 16
        pref 0,flags 0,cookielen 8,ss_id 402,cookie_high D0338947,cookie_low 69DCF79E

Table 3 describes the significant fields shown in the display.

Table 3 show ip bgp ipv4 unicast Field Descriptions 

Field
Description

BGP table version

Internal version number of the table. This number is incremented whenever the table changes.

local router ID

IP address of the router.

Status codes

Status of the table entry. The status is displayed at the beginning of each line in the table. It can be one of the following values:

s—Table entry is suppressed.

d—Table entry is damped.

h—Table entry history.

*—Table entry is valid.

>—Table entry is the best entry to use for that network.

i—Table entry was learned through an internal BGP (iBGP) session.

Origin codes

Origin of the entry. The origin code is displayed at the end of each line in the table. It can be one of the following values:

i—Entry originated from an Interior Gateway Protocol (IGP) and was advertised with a network router configuration command.

e—Entry originated from an Exterior Gateway Protocol (EGP).

?—Origin of the path is not clear. Usually, this is a router that is redistributed into BGP from an IGP.

Network

IP address of a network entity.

Next Hop

IP address of the next system that is used when forwarding a packet to the destination network. An entry of 0.0.0.0 indicates that the router has some non-BGP routes to this network.

Metric

If shown, the value of the interautonomous system metric.

LocPrf

Local preference value as set with the set local-preference route-map configuration command. The default value is 100.

Weight

Weight of the route as set using autonomous system filters.

Path

Autonomous system paths to the destination network. There can be one entry in this field for each autonomous system in the path.


Related Commands

Command
Description

show ip bgp

Displays entries in the BGP routing table.