Mpls

Configuring a Basic MPLS VPN
Document ID: 13733
Introduction Prerequisites Requirements Components Used Related Products Conventions Configure Network Diagram Configuration Procedures Configurations Verify Troubleshoot Related Information

Introduction
This document provides a sample configuration of a Multiprotocol Label Switching (MPLS) VPN when Border Gateway Protocol (BGP) or RoutingInformation Protocol (RIP) is present on the customer's site. When used with MPLS, the VPN feature allows several sites to interconnect transparently through a service provider's network. One service provider network can support several different IP VPNs. Each of these appears to its users as a private network, separate from all other networks. Within a VPN, each site can send IP packets to any othersite in the same VPN. Each VPN is associated with one or more VPN routing or forwarding instances (VRFs). A VRF consists of an IP routing table, a derived Cisco express forwarding (CEF) table, and a set of interfaces that use this forwarding table. The router maintains a separate routing and CEF table for each VRF. This prevents information being sent outside the VPN and allows the same subnet tobe used in several VPNs without causing duplicate IP address problems. The router using Multiprotocol BGP (MP−BGP) distributes the VPN routing information using the MP−BGP extended communities. For more information about the propagation of updates through a VPN, refer to these documents: • VPN Route Target Communities • BGP Distribution of VPN Routing Information • MPLS ForwardingPrerequisites
Requirements
There are no specific requirements for this document.

Components Used
The information in this document is based on these software and hardware versions: P and PE Routers • Cisco IOS® Software Release 12.2(6h) includes the MPLS VPN feature. • Any Cisco router from the 7200 series or higher supports P functionality. The Cisco 2691, as well as any 3640 series or higher routersupports PE functionality. C and CE Routers • You can use any router that can exchange routing information with its PE router. The information presented in this document was created from devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If you are working in a live network, ensure that you understand the potential impactof any command before using it.

Related Products
To implement the MPLS feature, you must have a router from the range of Cisco 2600 or higher. To select the required Cisco IOS with MPLS feature, use the Software Advisor ( registered customers only) . Also check for the additional RAM and Flash memory required to run the MPLS feature in the routers. WIC−1T, WIC−2T, and serial interfaces can beused.

Conventions
Refer to Cisco Technical Tips Conventions for more information on document conventions. The letters below represent the different types of routers and switches used. • PProvider's core router. • PEProvider's edge router. • CECustomer's edge router. • CCustomer's router. This diagram shows a typical configuration illustrating the conventions outlined above.

Configure
Inthis section, you are presented with the information to configure the features described in this document. Note: Use the Command Lookup Tool ( registered customers only) to find more information on the commands used in this document.

Network Diagram
This document uses this network setup:

Configuration Procedures
Refer to MPLS Virtual Private Networks for more information. Enabling ip cef Usethis procedure in order to enable ip cef. For improved performance, use ip cef distributed (where available). Complete these steps on the PEs after MPLS has been set up (configuring tag−switching ip on the interfaces).

1. Create one VRF for each VPN connected using the ip vrf command. When doing this: ♦ Specify the correct route distinguisher used for that VPN. This is used to extend the...