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Table Of Contents
MPLS Virtual Private Networks (VPNs)
BGP Distribution of VPN Routing Information
Related Features and Technologies
Supported Standards, MIBs and RFCs
Configuring BGP PE to PE or PE to CE Routing Sessions
Configuring RIP PE to CE Routing Sessions
Configuring Static Route PE to CE Routing Sessions
show tag-switching forwarding vrf
MPLS Virtual Private Networks (VPNs)
Feature History
12.0(5)T
This feature was introduced.
12.0(21)ST
This feature was implemented on the Cisco 10720 Internet router and integrated into Cisco IOS Release 12.0(21)ST.
12.0(22)S
This feature was implemented on the Cisco 12000 series Internet Router on the following line cards: the 6E3-SMB and 12E3-SMB line cards, the 6-port channelized T3 (6CT3-SMB) line card, the OC-192c/STM-64c Packet-over-SONET (POS) line card, and the Quad OC-48c STM-16c POS line card and integrated into Cisco IOS Release 12.0(22)S.
12.0(23)S
This feature was integrated into Cisco IOS Release 12.0(23)S. The ip route static inter-vrf command was introduced.
12.2(13)T
This feature was implemented on the Cisco 7200 and Cisco 7500 series routers and integrated into Cisco IOS Release 12.2(13)T. Support was added for the ip route static inter-vrf command.
This document describes the Multiprotocol Label Switching (MPLS) Virtual Private Network (VPN) feature and includes the following sections:
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Supported Standards, MIBs and RFCs
Feature Overview
The IP Virtual Private Network (VPN) feature for Multiprotocol Label Switching (MPLS) allows a Cisco IOS network to deploy scalable IPv4 Layer 3 VPN backbone services. An IP VPN is the foundation companies use for deploying or administering value-added services including applications and data hosting network commerce, and telephony services to business customers. In private local area networks (LANs), IP-based intranets have fundamentally changed the way companies conduct their business. Companies are moving their business applications to their intranets to extend over a wide area network (WAN). Companies are also embracing the needs of their customers, suppliers, and partners by using extranets (an intranet that encompasses multiple businesses). With extranets, companies reduce business process costs by facilitating supply-chain automation, electronic data interchange (EDI), and other forms of network commerce. To take advantage of this business opportunity, service providers must have an IP VPN infrastructure that delivers private network services to businesses over a public infrastructure.
IP Virtual Private Networks
To effectively implement an IP VPN in your facility, ensure that your IP VPN meets the following basic requirements:
Privacy—All IP VPNs offer privacy over a shared (public) network infrastructure. Most companies use an encrypted tunnel. This is only one of several ways to provide network and data privacy.
Scalability—For proper service delivery, VPNs must scale to serve hundreds of thousands of sites and users. Besides being a managed service, VPNs are also a management tool for service providers to control access to services. One example is Closed User Groups for data and voice services.
Flexibility—IP VPNs must handle the any-to-any traffic patterns characteristic of corporate intranets and extranets, in which data no longer flows to and from a central location. VPNs must also have the inherent flexibility to add new sites quickly, connect users over different media, and meet the increasingly sophisticated transport and bandwidth requirements of new intranet applications.
Predictable Performance—Performance needs vary widely requiring different classes of service, but the common requirement is that the performance is predictable. Examples of the ranges of performance requirements include:
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MPLS Virtual Private Networks
MPLS VPNs allow service providers to deploy scalable VPNs and build the foundation to deliver value-added services, including:
Connectionless Service—A significant technical advantage of MPLS VPNs is that they are connectionless. The Internet owes its success to its basic technology, TCP/IP. TCP/IP is built on packet-based, connectionless network paradigm. This means that no prior action is necessary to establish communication between hosts, making it easy for two parties to communicate. To establish privacy in a connectionless IP environment, current VPN solutions impose a connection-oriented, point-to-point overlay on the network. Even if it runs over a connectionless network, a VPN cannot take advantage of the ease of connectivity and multiple services available in connectionless networks. When you create a connectionless VPN, you do not need tunnels and encryption for network privacy, thus eliminating significant complexity.
Centralized Service—Building VPNs in Layer 3 allows delivery of targeted services to a group of users represented by a VPN. A VPN must give service providers more than a mechanism for privately connecting users to intranet services. It must also provide a way to flexibly deliver value-added services to targeted customers. Scalability is critical, because customers want to use services privately in their intranets and extranets. Because MPLS VPNs are seen as private intranets, you may use new IP services such as:
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You can customize several combinations of specialized services for individual customers. For example, a service that combines IP multicast with a low-latency service class enables video conferencing within an intranet.
Scalability—If you create a VPN using connection-oriented, point-to-point overlays, Frame Relay, or ATM virtual connections (VCs), the VPN's key deficiency is scalability. Specifically, connection-oriented VPNs without fully meshed connections between customer sites are not optimal. MPLS-based VPNs instead use the peer model and Layer 3 connectionless architecture to leverage a highly scalable VPN solution. The peer model requires a customer site to peer with only one provider edge (PE) router as opposed to all other CPE or customer edge (CE) routers that are members of the VPN. The connectionless architecture allows the creation of VPNs in Layer 3, eliminating the need for tunnels or VCs.
Other scalability issues of MPLS VPNs are due to the partitioning of VPN routes between PE routers and the further partitioning of VPN and IGP routes between PE routers and provider (P) routers in a core network.
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This increases the scalability of the provider's core and ensures that no one device is a scalability bottleneck.
Security—MPLS VPNs offer the same level of security as connection-oriented VPNs. Packets from one VPN do not inadvertently go to another VPN.
Security is provided in the following areas:
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Easy to Create—To take full advantage of VPNs, it must be easy for customers to create new VPNs and user communities. Because MPLS VPNs are connectionless, no specific point-to-point connection maps or topologies are required. You can add sites to intranets and extranets and form closed user groups. When you manage VPNs in this manner, it enables membership of any given site in multiple VPNs, maximizing flexibility in building intranets and extranets.
Flexible Addressing—To make a VPN service more accessible, customers of a service provider can design their own addressing plan, independent of addressing plans for other service provider customers. Many customers use private address spaces, as defined in RFC 1918, and do not want to invest the time and expense of converting to public IP addresses to enable intranet connectivity. MPLS VPNs allow customers to continue to use their present address spaces without network address translation (NAT) by providing a public and private view of the address. A NAT is required only if two VPNs with overlapping address spaces want to communicate. This enables customers to use their own unregistered private addresses, and communicate freely across a public IP network.
Integrated Class of Service (CoS) Support—CoS is an important requirement for many IP VPN customers. It provides the ability to address two fundamental VPN requirements:
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Network traffic is classified and labeled at the edge of the network before traffic is aggregated according to policies defined by subscribers and implemented by the provider and transported across the provider core. Traffic at the edge and core of the network can then be differentiated into different classes by drop probability or delay.
Straightforward Migration—For service providers to quickly deploy VPN services, use a straightforward migration path. MPLS VPNs are unique because you can build them over multiple network architectures, including IP, ATM, Frame Relay, and hybrid networks.
Migration for the end customer is simplified because there is no requirement to support MPLS on the customer edge (CE) router and no modifications are required to a customer's intranet.
For a list of platforms supported by MPLS VPNs, see the "Supported Platforms" section.
Figure 1 shows an example of a VPN with a service provider (P) backbone network, service provider edge routers (PE), and customer edge routers (CE).
Figure 1 VPNs with a Service Provider Backbone
A VPN contains customer devices attached to the CE routers. These customer devices use VPNs to exchange information between devices. Only the PE routers are aware of the VPNs.
Figure 2 shows five customer sites communicating within three VPNs. The VPNs can communicate with the following sites:
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Figure 2 Customer Sites within VPNs
VPN Operation
Each VPN is associated with one or more VPN routing/forwarding instances (VRFs). A VRF defines the VPN membership of a customer site attached to a PE router. A VRF consists of an IP routing table, a derived Cisco Express Forwarding (CEF) table, a set of interfaces that use the forwarding table, and a set of rules and routing protocol parameters that control the information that is included into the routing table.
A one-to-one relationship does not necessarily exist between customer sites and VPNs. A given site can be a member of multiple VPNs, as shown in Figure 2. However, a site can only associate with only one VRF. A customer site's VRF contains all the routes available to the site from the VPNs of which it is a member.
Packet forwarding information is stored in the IP routing table and the CEF table for each VRF. A separate set of routing and CEF tables is maintained for each VRF. These tables prevent information from being forwarded outside a VPN, and also prevent packets that are outside a VPN from being forwarded to a router within the VPN.
VPN Route Target Communities
The distribution of VPN routing information is controlled through the use of VPN route target communities, implemented by Border Gateway Protocol (BGP) extended communities. Distribution of VPN routing information works as follows:
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BGP Distribution of VPN Routing Information
A service provider edge (PE) router can learn an IP prefix from a customer edge (CE) router by static configuration, through a BGP session with the CE router, or through the routing information protocol (RIP) exchange with the CE router. The IP prefix is a member of the IPv4 address family. After it learns the IP prefix, the PE converts it into a VPN-IPv4 prefix by combining it with an 8-byte route distinguisher (RD). The generated prefix is a member of the VPN-IPv4 address family. It serves to uniquely identify the customer address, even if the customer site is using globally nonunique (unregistered private) IP addresses.
The route distinguisher used to generate the VPN-IPv4 prefix is specified by a configuration command associated with the VRF on the PE router.
BGP distributes reachability information for VPN-IPv4 prefixes for each VPN. BGP communication takes place at two levels: within IP domains, known as an autonomous systems (interior BGP or IBGP) and between autonomous systems (external BGP or EBGP). PE-PE or PE-RR (route reflector) sessions are IBGP sessions, and PE-CE sessions are EBGP sessions.
BGP propagates reachability information for VPN-IPv4 prefixes among PE routers by means of the BGP multiprotocol extensions (refer to RFC 2283, Multiprotocol Extensions for BGP-4) which define support for address families other than IPv4. It does this in a way that ensures that the routes for a given VPN are learned only by other members of that VPN, enabling members of the VPN to communicate with each other.
MPLS Forwarding
Based on routing information stored in the VRF IP routing table and VRF CEF table, packets are forwarded to their destination using MPLS.
A PE router binds a label to each customer prefix learned from a CE router and includes the label in the network reachability information for the prefix that it advertises to other PE routers. When a PE router forwards a packet received from a CE router across the provider network, it labels the packet with the label learned from the destination PE router. When the destination PE router receives the labeled packet, it pops the label and uses it to direct the packet to the correct CE router. Label forwarding across the provider backbone is based on either dynamic label switching or traffic engineered paths. A customer data packet carries two levels of labels when traversing the backbone:
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Benefits
This section describes the benefits of VPNs in general and MPLS VPNs in particular.
IP VPNs are attractive because they have the following benefits:
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However, conventional VPNs do not scale well. They are based on creating and maintaining a full mesh of tunnels or permanent virtual circuits among all sites belonging to a particular VPN, using:
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The overhead required to provision and manage these connection-based schemes cannot be supported in a provider network that must support hundreds or thousands of VPNs, each with tens or hundreds or thousands of sites and thousands or tens of thousands of routes.
MPLS VPNs, which are created in Layer 3, are connectionless, and therefore substantially more scalable and easier to build and manage than conventional VPNs. In addition, you can add value-added services, such as application and data hosting, network commerce, and telephony services to a particular MPLS VPN because the service provider's backbone recognizes each MPLS VPN as a separate, connectionless IP network.
MPLS VPNs offer the following benefits:
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Related Features and Technologies
VPNs may be used with the Class of Service (CoS) feature for MPLS.
Related Documents
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Supported Platforms
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Determining Platform Support Through Cisco Feature Navigator
Cisco IOS software is packaged in feature sets that are supported on specific platforms. To obtain updated information about platform support for this feature, access Cisco Feature Navigator. Cisco Feature Navigator dynamically updates the list of supported platforms as new platform support is added for the feature.
Cisco Feature Navigator is a web-based tool that enables you to determine which Cisco IOS software images support a specific set of features and which features are supported in a specific Cisco IOS image. You can search by feature or release. In the release section, you can compare releases side by side to display both the features unique to each software release and the features that releases have in common.
To access Cisco Feature Navigator, you must have an account on Cisco.com. If you have forgotten or lost your account information, send a blank e-mail to cco-locksmith@cisco.com. An automatic check will verify that your e-mail address is registered with Cisco.com. If the check is successful, account details with a new random password will be e-mailed to you. Qualified users can establish an account on Cisco.com by following the directions found at this URL:
Cisco Feature Navigator is updated regularly when major Cisco IOS software releases and technology releases occur. For the most current information, go to the Cisco Feature Navigator home page at the following URL:
Availability of Cisco IOS Software Images
Platform support for particular Cisco IOS software releases is dependent on the availability of the software images for those platforms. Software images for some platforms may be deferred, delayed, or changed without prior notice. For updated information about platform support and availability of software images for each Cisco IOS software release, refer to the online release notes or, if supported, Cisco Feature Navigator.
Supported Standards, MIBs and RFCs
Standards
No new or modified standards are supported by this feature.
MIBs
No new or modified MIBs are supported by this feature.
To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:
http://tools.cisco.com/ITDIT/MIBS/servlet/index
If Cisco MIB Locator does not support the MIB information that you need, you can also obtain a list of supported MIBs and download MIBs from the Cisco MIBs page at the following URL:
http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml
To access Cisco MIB Locator, you must have an account on Cisco.com. If you have forgotten or lost your account information, send a blank e-mail to cco-locksmith@cisco.com. An automatic check will verify that your e-mail address is registered with Cisco.com. If the check is successful, account details with a new random password will be e-mailed to you. Qualified users can establish an account on Cisco.com by following the directions found at this URL:
RFCs
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Prerequisites
Your network must be running the following Cisco IOS services before you configure VPN operation:
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Configuration Tasks
See the following sections to configure and verify VPNs:
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Defining VPNs
To define VPN routing instances, use the following commands beginning in global configuration mode on the PE router:
Configuring BGP PE to PE or PE to CE Routing Sessions
To configure BGP PE to PE to PE to CE routing sessions in a provider network, use the following commands beginning in global configuration mode on the PE router:
Configuring RIP PE to CE Routing Sessions
To configure RIP PE to CE routing sessions, use the following commands beginning in global configuration mode on the PE router:
Configuring Static Route PE to CE Routing Sessions
To configure static route PE to CE routing sessions, use the following commands beginning in global configuration mode on the PE router:
Verifying VPN Operation
To verify VPN operation, use the following commands in privileged EXEC mode:
Configuration Examples
This section provides a sample configuration file from a PE router.
ip cef distributed ! CEF switching is pre-requisite for label Switchingframe-relay switching!ip vrf vrf1 ! Define VPN Routing instance vrf1rd 100:1route-target both 100:1 ! Configure import and export route-targets for vrf1!ip vrf vrf2 ! Define VPN Routing instance vrf2rd 100:2route-target both 100:2 ! Configure import and export route-targets for vrf2route-target import 100:1 ! Configure an additional import route-target for vrf2import map vrf2_import ! Configure import route-map for vrf2!interface lo0ip address 10.13.0.13 255.255.255.255!interface atm9/0/0 ! Backbone link to another Provider router!interface atm9/0/0.1 tag-switchingip unnumbered loopback0no ip directed-broadcastmpls atm vpi 2-5mpls ipinterface atm5/0no ip addressno ip directed-broadcastatm clock INTERNALno atm ilmi-keepaliveinterface Ethernet1/0ip address 3.3.3.5 255.255.0.0no ip directed-broadcastno ip mroute-cacheno keepaliveinterface Ethernet5/0/1 ! Set up Ethernet interfaceip vrf forwarding vrf1 ! as VRF link to a CE routerip address 10.20.0.13 255.255.255.0!interface hssi 10/1/0hssi internal-clockencaps frframe-relay intf-type dceframe-relay lmi-type ansi!interface hssi 10/1/0.16 point-to-pointip vrf forwarding vrf2ip address 10.20.1.13 255.255.255.0frame-relay interface-dlci 16 ! Set up Frame Relay PVC! ! subinterface as link to another! ! CE router!router bgp 1 ! Configure BGP sessionsno synchronizationno bgp default ipv4-activate ! Deactivate default IPv4 advertisementsneighbor 10.15.0.15 remote-as 1 ! Define IBGP session with another PEneighbor 10.15.0.15 update-source lo0!address-family vpnv4 unicast ! Activate PE exchange of VPNv4 NLRIneighbor 10.15.0.15 activateexit-address-family!address-family ipv4 unicast vrf vrf1 ! Define BGP PE-CE session for vrf1redistribute staticredistribute connectedneighbor 10.20.0.60 remote-as 65535neighbor 10.20.0.60 activateno auto-summaryexit-address-family!address-family ipv4 unicast vrf vrf2 ! Define BGP PE-CE session for vrf2redistribute staticredistribute connectedneighbor 10.20.1.11 remote-as 65535neighbor 10.20.1.11 update-source h10/1/0.16neighbor 10.20.1.11 activateno auto-summaryexit-address-family!! Define a VRF static routeip route vrf vrf1 12.0.0.0 255.0.0.0 e5/0/1 10.20.0.60!route-map vrf2_import permit 10 ! Define import route-map for vrf2....Command Reference
This section documents new and modified commands. All other commands used with this feature are documented in the Cisco IOS Release 12.0 command references.
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address-family
To enter the address family submode for configuring routing protocols, such as Border Gateway Protocol (BGP), Routing Information Protocol (RIP) and static routing, use the address-family command in router configuration mode. To disable the address family submode for configuring routing protocols, use the no form of this command.
VPN-IPv4 unicast
address-family vpnv4 [unicast]
no address-family vpnv4 [unicast]
IPv4 unicast
address-family ipv4 [unicast]
no address-family ipv4 [unicast]
IPv4 unicast with CE router
address-family ipv4 [unicast] vrf vrf-name
no address-family ipv4 [unicast] vrf vrf-name
Syntax Description
Defaults
Routing information for address family IPv4 is advertised by default when you configure a BGP session using the neighbor...remote-as command unless you execute the no bgp default ipv4-activate command.
Command Modes
Router configuration
Command History
Usage Guidelines
Using the address-family command puts you in address family configuration submode (prompt: (config-router-af)# ). Within this submode, you can configure address-family specific parameters for routing protocols, such as BGP, that can accommodate multiple Layer 3 address families.
To leave address family configuration submode and return to router configuration mode, type exit-address-family, or simply exit.
Examples
The following example shows how to put the router into address family configuration submode for the VPNv4 address family. Within the submode, you can configure advertisement of NLRI for the VPNv4 address family using neighbor activate and other related commands:
Router(config)# router bgp 100Router(config-router)# address-family vpnv4Router(config-router-af)#The following example shows how to put the router into address family configuration submode for the IPv4 address family. Use this form of the command, which specifies a VRF, only to configure routing exchanges between provider edge (PE) and customer edge (CE) devices. This address-family command causes subsequent commands entered in the submode to be executed in the context of VRF vrf2.
Router(config)# router bgp 100Router(config-router)# address-family ipv4 unicast vrf vrf2Router(config-router-af)#Within the submode, you can use neighbor activate and other related commands to accomplish the following:
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Related Commands
Exits from the address family submode
Enables the exchange of information with a BGP neighboring router.
clear ip route vrf
To remove routes from the Virtual Private Network (VPN) routing/forwarding (VRF) routing table, use the clear ip route vrf command in privileged EXEC mode.
clear ip route vrf vrf-name {* | network [mask]}
Syntax Description
Defaults
No default behavior or values.
Command Modes
Privileged EXEC
Command History
Usage Guidelines
Use this command to clear routes from the routing table. Use the asterisk (*) to delete all routes from the forwarding table for a specified VRF, or enter the address and mask of a particular network to delete the route to that network.
Examples
The following command shows how to remove the route to the network 10.13.0.0 in the vpn1 routing table:
Router# clear ip route vrf vpn1 10.13.0.0Related Commands
debug ip bgp
To display information related to processing Border Gateway Protocol (BGP) routing, use the debug ip bgp command in privileged EXEC mode. To disable the display of BGP information, use the no form of this command.
debug ip bgp [A.B.C.D. | dampening | events | in | keepalives | out | updates | vpnv4]
no debug ip bgp [A.B.C.D. | dampening | events | in | keepalives | out | updates | vpnv4]
Syntax Description
Defaults
No default behavior or values.
Command Modes
Privileged EXEC
Command History
Examples
The following example displays the output from this command:
Router# debug ip bgp vpnv403:47:14:vpn:bgp_vpnv4_bnetinit:100:2:58.0.0.0/803:47:14:vpn:bnettable add:100:2:58.0.0.0 / 803:47:14:vpn:bestpath_hook route_tag_change for vpn2:58.0.0.0/255.0.0.0(ok)03:47:14:vpn:bgp_vpnv4_bnetinit:100:2:57.0.0.0/803:47:14:vpn:bnettable add:100:2:57.0.0.0 / 803:47:14:vpn:bestpath_hook route_tag_change for vpn2:57.0.0.0/255.0.0.0(ok)03:47:14:vpn:bgp_vpnv4_bnetinit:100:2:14.0.0.0/803:47:14:vpn:bnettable add:100:2:14.0.0.0 / 803:47:14:vpn:bestpath_hook route_tag_chacle ip bgp *nge for vpn2:14.0.0.0/255.0.0.0(ok)exit-address-family
To exit from the address family submode, use the exit-address-family command in address family submode.
exit-address-family
Syntax Description
This command has no arguments or keywords.
Defaults
No default behavior or values.
Command Modes
Address family submode
Command History
Usage Guidelines
This command can be abbreviated to exit.
Examples
The following example shows how to exit the address-family command submode:
Router(config-router-af)# exit-address-familyRelated Commands
import map
To configure an import route map for a Virtual Private Network (VPN) routing/forwarding instance (VRF), use the import map command in VRF submode.
import map route-map
Syntax Description
Defaults
A VRF has no import route map unless one is configured using the import map command.
Command Modes
VRF submode
Command History
Usage Guidelines
Use an import map command when an application requires finer control over the routes imported into a VRF than provided by the import and export extended communities configured for the importing and exporting VRF.
The import-map command associates a route map with the specified VRF. You can filter routes that are eligible for import into a VRF, based on the route target extended community attributes of the route, through the use of a route map. The route map might deny access to selected routes from a community that is on the import list.
Examples
The following example shows how to configure an import route map for a VRF:
Router(config)# ip vrf vrf_blueRouter(config-vrf)# import map blue_import_mapRelated Commands
Enters VRF configuration mode.
Configures import and export extended community attributes for the VRF.
Displays information about a VRF or all VRFs.
ip route static inter-vrf
To allow static routes to point to Virtual Private Network (VPN) routing/forwarding (VRF) interfaces in VRFs other than those to which the static route belongs, use the ip route static inter-vrf command in global configuration mode. To prevent static routes from pointing to VRF interfaces in VRFs to which they do not belong, use the no form of this command.
ip route static inter-vrf
no ip route static inter-vrf
Syntax Description
This command has no arguments or keywords.
Defaults
By default, static routes are allowed to point to VRF interfaces in any VRF.
Command Modes
Global configuration
Command History
12.0(23)S
This command was introduced.
12.2(13)T
This command was integrated into Cisco IOS 12.2(13)T.
Usage Guidelines
The ip route static inter-vrf command is turned on by default. The no ip route static inter-vrf command causes the respective routing table (global or VRF) to reject the installation of static routes if the outgoing interface belongs to a different VRF than the static route being configured. This prevents security problems that can occur when static routes that point to a VRF interface in a different VRF are misconfigured. You are notified when a static route is rejected, then you can reconfigure it.
For example, a static route is defined on a provider edge (PE) router to forward Internet traffic to a customer on the interface pos1/0, as follows:
Router(config)# ip route 10.1.1.1 255.255.255.255 pos 1/0Mistakenly, the same route is configured with the next-hop as the VRF interface pos10/0:
Router(config)# ip route 10.1.1.1 255.255.255.255 pos 10/0By default, Cisco IOS accepts the command and starts forwarding the traffic to both pos1/0 (Internet) and pos10/0 (VPN) interfaces.
If the static route is already configured that points to a VRF other than the one to which the route belongs when you issue the no ip route static inter-vrf command, the offending route is uninstalled from the routing table and a message similar to the following is sent to the console:
01:00:06: %IPRT-3-STATICROUTESACROSSVRF: Un-installing static route x.x.x.x/32 from global routing table with outgoing interface intx/xIf you enter the no ip route static inter-vrf command before a static route is configured that points to a VRF interface in a different VRF, the static route is not installed in the routing table and a message is sent to the console.
In the following example, configuring the no ip route static inter-vrf command prevents traffic from following an unwanted path. A VRF static route points to a global interface or any other VRF interface as shown in the following ip route vrf commands:
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Router(config)# ip route vrf vpn1 10.10.1.1 255.255.255.255 ser1/0.0•
Router(config)# ip route vrf vpn1 10.10.1.1 255.255.255.255 ser1/0.1With the no ip route static inter-vrf command configured, these static routes are not installed into the vpn1 routing table because the static routes point to an interface that is not in the same VRF.
If you require a VRF static route to point to a global interface, you can use the global keyword with the ip route vrf command:
Router(config)# ip route vrf vpn1 10.12.1.1 255.255.255.255 ser1/0.0 7.0.0.1 globalThe global keyword allows the VRF static route to point to a global interface even when the no ip route static inter-vrf command is configured.
Examples
The following example shows how to prevent static routes that point to VRF interfaces in a different VRF:
Router(config)# no ip route static inter-vrfRelated Commands
ip route vrf
To establish static routes for a Virtual Private Network (VPN) routing/forwarding instance (VRF), use the ip route vrf command in global configuration mode. To disable static routes, use the no form of this command.
ip route vrf vrf-name prefix mask [next-hop-address] [interface {interface-number}] [global] [distance] [permanent] [tag tag]
no ip route vrf vrf-name prefix mask [next-hop-address] [interface {interface-number}] [global] [distance] [permanent] [tag tag]
Syntax Description
Defaults
No default behavior or values.
Command Modes
Global configuration
Command History
Usage Guidelines
Use a static route when the Cisco IOS software cannot dynamically build a route to the destination.
If you specify an administrative distance when you set up a route, you are flagging a static route that can be overridden by dynamic information. For example, Interior Gateway Routing Protocol (IGRP)-derived routes have a default administrative distance of 100. To set a static route to be overridden by an IGRP dynamic route, specify an administrative distance greater than 100. Static routes each have a default administrative distance of 1.
Static routes that point to an interface are advertised through Routing Information Protocol (RIP), IGRP, and other dynamic routing protocols, regardless of whether the routes are redistributed into those routing protocols. That is, static routes configured by specifying an interface lose their static nature when installed into the routing table.
However, if you define a static route to an interface not defined in a network command, no dynamic routing protocols advertise the route unless a redistribute static command is specified for these protocols.
Examples
The following command shows how to reroute packets addressed to network 137.23.0.0 in VRF vpn3 to router 131.108.6.6:
Router(config)# ip route vrf vpn3 137.23.0.0 255.255.0.0 131.108.6.6Related Commands
ip vrf
To configure a Virtual Private Network (VPN) routing/forwarding (VRF) routing table, use the ip vrf command in global configuration mode. To remove a VRF routing table, use the no form of this command.
ip vrf vrf-name
no ip vrf vrf-name
Syntax Description
Defaults
No VRFs are defined. No import or export lists are associated with a VRF. No route maps are associated with a VRF.
Command Modes
Global configuration
Command History
Usage Guidelines
The ip vrf vrf-name command creates a VRF routing table and a CEF (forwarding) table, both named vrf-name. Associated with these tables is the default route distinguisher value route-distinguisher.
Examples
The following example shows how to import a route map to a VRF:
Router(config)# ip vrf vpn1Router(config-vrf)# rd 100:2Router(config-vrf)# route-target both 100:2Router(config-vrf)# route-target import 100:1Related Commands
ip vrf forwarding
To associate a Virtual Private Network (VPN) routing/forwarding instance (VRF) with an interface or subinterface, use the ip vrf forwarding command in interface configuration mode. To disassociate a VRF, use the no form of this command.
ip vrf forwarding vrf-name
no ip vrf forwarding vrf-name
Syntax Description
Defaults
The default for an interface is the global routing table.
Command Modes
Interface configuration
Command History
Usage Guidelines
Use this command to associate an interface with a VRF. Executing this command on an interface removes the IP address. The IP address should be reconfigured.
Examples
The following example shows how to link a VRF to ATM interface 0/0:
Router(config)# interface atm0/0Router(config-if)# ip vrf forwarding vpn1Related Commands
neighbor activate
To enable the exchange of information with a Border Gateway Protocol (BGP) neighboring router, use the neighbor activate command in router configuration mode. To disable the exchange of an address with a neighboring router, use the no form of this command.
neighbor {ip-address | peer-group-name} activate
no neighbor {ip-address | peer-group-name} activate
Syntax Description
Defaults
The exchange of addresses with neighbors is enabled by default for the Virtual Private Network (VPN) IPv4 address family. You can disable IPv4 address exchange using the general command no default bgp ipv4 activate, or you can disable it for a particular neighbor by using the no form of this command.
For all other address families, address exchange is disabled by default. You can explicitly activate the default command by using the appropriate address family submode.
Command Modes
Router configuration
Command History
Usage Guidelines
Use this command to enable or disable the exchange of addresses with a neighboring router.
Examples
The following example shows how to activates the exchange of the customer IP address 10.15.0.15 to a neighboring router.
Router(config)# router bgp 100Router(config-router)# neighbor 10.15.0.15 remote-as 100Router(config-router)# neighbor 10.15.0.15 update-source loopback0Router(config-router)# address-family vpnv4 unicastRouter(config-router-af)# neighbor 10.15.0.15 activateRouter(config-router-af)# exit-address-familyRelated Commands
rd
To create routing and forwarding tables for a Virtual Private Network (VPN) routing/forwarding instance (VRF), use the rd command in VRF configuration submode.
rd route-distinguisher
Syntax Description
Defaults
There is no default. A route distinguisher (RD) must be configured for a VRF to be functional.
Command Modes
VRF configuration submode
Command History
Usage Guidelines
An RD creates routing and forwarding tables and specifies the default route distinguisher for a VPN. The RD is added to the beginning of the customer's IPv4 prefixes to change them into globally unique VPN-IPv4 prefixes.
An RD is either
•
•
You can enter an RD in either of these formats:
16-bit AS number: your 32-bit number
For example, 101:332-bit IP address: your 16-bit number
For example, 192.168.122.15:1Examples
The following example shows how to configures a default RD for two VRFs. The example shows the use of both AS-related and IP address-related RDs:
Router(config)# ip vrf vrf_blueRouter(config-vrf)# rd 100:3Router(config-vrf)# ip vrf vrf_redRouter(config-vrf)# rd 173.13.0.12:200Related Commands
route-target
To create a route-target extended community for a Virtual Private Network (VPN) routing/forwarding instance (VRF), use the route-target command in VRF configuration submode. To disable the configuration of a route-target community option, use the no form of this command.
route-target {import | export | both} route-target-ext-community
no route-target {import | export | both} route-target-ext-community
Syntax Description
Defaults
A VRF has no route-target extended community attributes associated with it until the attributes are specified by the route-target command.
Command Modes
VRF configuration submode
Command History
Usage Guidelines
The route-target command creates lists of import and export route target extended communities for the specified VRF. Execute the command one time for each target community. Learned routes that carry a specific route target extended community are imported into all VRFs configured with that extended community as an import route target. Routes learned from a VRF site (for example, by Border Gateway Protocol (BGP), Routing Information Protocol (RIP), or static route configuration) contain export route targets for extended communities configured for the VRF added as route attributes to control the VRFs into which the route is imported.
The route-target specifies a target VPN extended community. Like a route-distinguisher, an extended community is composed of either an autonomous system number and an arbitrary number, or an IP address and an arbitrary number. You can enter the numbers in either of these formats:
•
For example, 101:3•
For example, 192.168.122.15:1Examples
The following example shows how to configure route-target extended community attributes for a VRF. The result of the command sequence is that VRF vrf_blue has two export extended communities (1000:1 and 1000:2) and two import extended communities (1000:1 and 173.27.0.130:200).
Router(config)# ip vrf vrf_blueRouter(config-vrf)# route-target both 1000:1Router(config-vrf)# route-target export 1000:2Router(config-vrf)# route-target import 173.27.0.130:200Related Commands
show ip bgp vpnv4
To display Virtual Private network (VPN) address information from the Border Gateway Protocol (BGP) table, use the show ip bgp vpnv4 command in privileged EXEC mode.
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]
Syntax Description
Defaults
No default behavior or values.
Command Modes
Privileged EXEC
Command History
Usage Guidelines
Use this command to display VPNv4 information from the BGP database. The show ip bgp vpnv4 all command displays all available VPNv4 information. The show ip bgp vpnv4 summary command displays BGP neighbor status.
Examples
The following example shows output for all available VPNv4 information in a BGP routing table:
Router# show ip bgp vpnv4 allBGP table version is 18, local router ID is 14.14.14.14Status codes: s suppressed, d damped, h history, * valid, > best, i - internalOrigin codes: i - IGP, e - EGP,? - incompleteNetwork Next Hop Metric LocPrf Weight PathRoute Distinguisher: 100:1 vrf1*> 11.0.0.0 50.0.0.1 0 0 101 i*>i12.0.0.0 13.13.13.13 0 100 0 102 i*> 50.0.0.0 50.0.0.1 0 0 101 i*>i51.0.0.0 13.13.13.13 0 100 0 102 iTable 1 describes the fields shown in the example.
The following example shows how to display a table of labels for NLRIs that have a route-distinguisher value of 100:1.
Router# show ip bgp vpnv4 rd 100:1 tagsNetwork Next Hop In tag/Out tagRoute Distinguisher: 100:1 (vrf1)2.0.0.0 10.20.0.60 34/notag10.0.0.0 10.20.0.60 35/notag12.0.0.0 10.20.0.60 26/notag10.20.0.60 26/notag13.0.0.0 10.15.0.15 notag/26Table 2 describes the fields shown in the example.
The following example shows VPNv4 routing entries for the VRF called vrf1.
Router# show ip bgp vpnv4 vrf vrf1BGP table version is 18, local router ID is 14.14.14.14Status codes: s suppressed, d damped, h history, * valid, > best, i - internalOrigin codes: i - IGP, e - EGP,? - incompleteNetwork Next Hop Metric LocPrf Weight PathRoute Distinguisher: 100:1 (vrf1)*> 11.0.0.0 50.0.0.1 0 0 101 i*>i12.0.0.0 13.13.13.13 0 100 0 102 i*> 50.0.0.0 50.0.0.1 0 0 101 i*>i51.0.0.0 13.13.13.13 0 100 0 102 iTable 3 describes the fields shown in the example.
Related Commands
show ip cef vrf
To display the CEF forwarding table associated with a Virtual Private Network (VPN) routing/forwarding instance (VRF), use the show ip cef vrf command in privileged EXEC mode.
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]]
Syntax Description
Defaults
No default behavior or values.
Command Modes
Privileged EXEC
Command History
Usage Guidelines
Used with only the vrf-name argument, the show ip cef vrf command shows a shortened display of the CEF table.
Used with the detail keyword, the show ip cef vrf command shows detailed information for all CEF table entries.
Examples
This example shows the forwarding table associated with the VRF called vrf1:
Router# show ip cef vrf vrf1Prefix Next Hop Interface0.0.0.0/32 receive11.0.0.0/8 50.0.0.1 Ethernet1/312.0.0.0/8 52.0.0.2 POS6/050.0.0.0/8 attached Ethernet1/350.0.0.0/32 receive50.0.0.1/32 50.0.0.1 Ethernet1/350.0.0.2/32 receive50.255.255.255/32 receive51.0.0.0/8 52.0.0.2 POS6/0224.0.0.0/24 receive255.255.255.255/32 receiveTable 4 describes the fields shown in the example.
Table 4 show ip cef vrf Field Descriptions
Prefix
Specifies the network prefix.
Next Hop
Specifies the BGP next hop address.
Interface
Specifies the VRF interface.
Related CommandsRelated Commands
show ip protocols vrf
To display the routing protocol information associated with a Virtual Private Network (VPN) routing/forwarding instance (VRF), use the show ip protocols vrf command in privileged EXEC mode.
show ip protocols vrf vrf-name
Syntax Description
Defaults
No default behavior or values.
Command Modes
Privileged EXEC mode
Command History
Usage Guidelines
Use this command to display routing information associated with a VRF.
Examples
The following example displays information about a VRF called vpn2:
Router# show ip protocols vrf vpn2Routing Protocol is "bgp 100"Sending updates every 60 seconds, next due in 0 secOutgoing update filter list for all interfaces isIncoming update filter list for all interfaces isIGP synchronization is disabledAutomatic route summarization is disabledRedistributing:connected, staticRouting for Networks:Routing Information Sources:Gateway Distance Last Update13.13.13.13 200 02:20:5418.18.18.18 200 03:26:15Distance:external 20 internal 200 local 200Table 5 describes the fields shown in the example.
Related Commands
show ip route vrf
To display the IP routing table associated with a Virtual Private Network (VPN) routing/forwarding instance (VRF), use the show ip route vrf command in privileged EXEC mode.
show ip route vrf vrf-name [connected] [protocol [as-number] [tag] [output-modifiers]]
[list number [output-modifiers]] [profile] [static [output-modifiers]]
[summary [output-modifiers]] [supernets-only [output-modifiers]]Syntax Description
Command Modes
No default behavior or values.
Command Modes
Privileged EXEC
Command History
Usage Guidelines
This command displays specified information from the IP routing table of a VRF.
Examples
This example shows the IP routing table associated with the VRF called vrf1:
Router# show ip route vrf vrf1Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGPD - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter areaN1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGPi - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, * - candidate defaultU - per-user static route, o - ODRT - traffic engineered routeGateway of last resort is not setB 51.0.0.0/8 [200/0] via 13.13.13.13, 00:24:19C 50.0.0.0/8 is directly connected, Ethernet1/3B 11.0.0.0/8 [20/0] via 50.0.0.1, 02:10:22B 12.0.0.0/8 [200/0] via 13.13.13.13, 00:24:20This example shows BGP entries in the IP routing table associated with the VRF called vrf1:
Router# show ip route vrf vrf1 bgpB 51.0.0.0/8 [200/0] via 13.13.13.13, 03:44:14B 11.0.0.0/8 [20/0] via 51.0.0.1, 03:44:12B 12.0.0.0/8 [200/0] via 13.13.13.13, 03:43:14Related Commands
Displays the CEF forwarding table associated with a VRF.
Displays VRFs and associated interfaces.
show ip vrf
To display the set of defined Virtual Private Network (VPN) routing/forwarding instances (VRF) and associated interfaces, use the show ip vrf command in privileged EXEC mode.
show ip vrf [{brief | detail | interfaces}] [vrf-name] [output-modifiers]
Syntax Description
Defaults
When no optional parameters are specified, the command shows concise information about all configured VRFs.
Command Modes
Privileged EXEC
Command History
Usage Guidelines
Use this command to display information about VRFs. Two levels of detail are available: use the brief keyword or no keyword to display concise information, or use the detail keyword to display all information. To display information about all interfaces bound to a particular VRF, or to any VRF, use the interfaces keyword.
Examples
This example shows brief information for the VRFs currently configured:
Router# show ip vrfName Default RD Interfacesvrf1 100:1 Ethernet1/3vrf2 100:2 Ethernet0/3Table 6 describes the fields shown in the example.
Table 6 show vrf Field Descriptions
Name
Specifies the VRF name.
Default RD
Specifies the default route distinguisher.
Interfaces
Specifies the network interfaces.
This example shows detailed information for the VRF called vrf1:
Router# show ip vrf detail vrf1VRF vrf1; default RD 100:1Interfaces:Ethernet1/3Connected addresses are in global routing tableExport VPN route-target communitiesRT:100:1Import VPN route-target communitiesRT:100:1No import route-mapTable 7 describes the fields shown in this example.
This example shows the interfaces bound to a particular VRF:
router# show ip vrf interfacesInterface IP-Address VRF ProtocolEthernet2 130.22.0.33 blue_vrf upEthernet4 130.77.0.33 hub uprouter#Table 8 describes the fields shown in the example.
Related Commands
show tag-switching forwarding vrf
To display label forwarding information for advertised Virtual Private Network (VPN) routing/forwarding (VRF) routes, use the show tag-switching forwarding vrf command in privileged EXEC mode. To disable the display of label forwarding information, use the no form of this command.
show tag-switching forwarding vrf vrf-name [ip-prefix/length [mask]] [detail]
[output-modifiers]no show tag-switching forwarding vrf vrf-name [ip-prefix/length [mask]] [detail]
[output-modifiers]Syntax Description
Command Types
No default behavior or values.
Command Modes
Privileged EXEC
Command History
Usage Guidelines
Use this command to display label forwarding entries associated with a particular VRF or IP prefix.
Examples
The following example shows label forwarding entries that correspond to the VRF called vpn1:
Router# show tag-switching forwarding vrf vrf1 detailRelated Commands
Displays VRFs and associated interfaces.
show tag-switching forwarding-table
Displays the contents of the LFIB.
Glossary
ATM edge LSR—A router that is connected to the ATM LSR cloud through LSC-ATM interfaces. The ATM edge LSR adds labels to unlabeled packets and strips labels from labeled packets.
ATM-LSR—A label switch router with a number of LSC-ATM interfaces. The router forwards the cells among these interfaces using labels carried in the VPI/VCI field.
BGP—Border Gateway Protocol. Interdomain routing protocol that exchanges reachability information with other BGP systems. It is defined in RFC 1163.
CEF—Cisco Express Forwarding. An advanced Layer 3 IP switching technology. CEF optimizes network performance and scalability for networks with large and dynamic traffic patterns.
CE router—customer edge router. A router that is part of a customer network and that interfaces to a provider edge (PE) router. CE routers are not aware of associated VPNs.
CoS—class of service. A feature that provides scalable, differentiated types of service across an MPLS network.
GRE—generic routing encapsulation. A tunneling protocol developed by Cisco that can encapsulate a wide variety of protocol packet types inside IP tunnels, creating a virtual point-to-point link to Cisco routers at remote points over an IP internetwork. By connecting multiprotocol subnetworks in a single-protocol backbone environment, IP tunneling that uses GRE allows network expansion across a single-protocol backbone environment.
IGP—Interior Gateway Protocol. An Internet protocol used to exchange routing information within an autonomous system. Examples of common IBGPs include IGRP, OSPF, and RIP.
IS-IS—Intermediate System-to-Intermediate System. OSI link-state hierarchical routing protocol in which ISs (routers) exchange routing information based on a single metric to determine network topology.
LSA—link-state advertisement. A broadcast packet used by link-state protocols. The LSA contains information about neighbors and path costs and is used by the receiving router to maintain a routing table.
LSP—label-switched path. A sequence of hops (R0...Rn) in which a packet travels from R0 to Rn through label switching mechanisms. A label-switched path can be established dynamically, based on normal routing mechanisms, or through configuration.
LSP tunnel—label-switched path tunnel. A configured connection between two routers, in which MPLS is used to carry the packet.
MPLS—Multiprotocol Label Switching. An emerging industry standard. Switching method that forwards IP traffic using a label. This label instructs the routers and the switches in the network where to forward the packets based on preestablished IP routing information.
NLRI—Network Layer Reachability Information. BGP sends routing update messages containing NLRI to describe a route and how to get there. In this context, an NLRI is a prefix. A BGP update message carries one or more NLRI prefixes and the attributes of a route for the NLRI prefixes; the route attributes include a BGP next hop gateway address, community values, and other information.
PE router—provider edge router. A router that is part of a service provider's network connected to a customer edge (CE) router. All VPN processing occurs in the PE router.
RD—route distinguisher. An 8-byte value that is concatenated with an IPv4 prefix to create a unique VPN IPv4 prefix.
RIP—Routing Information Protocol. An IGP used to exchange routing information within an autonomous system, RIP uses hop count as a routing metric.
traffic engineering—The techniques and processes used to cause routed traffic to travel through the network on a path other than the one that would have been chosen if standard routing methods had been used.
traffic engineering tunnel—A label-switched path tunnel that is used for engineering traffic. It is set up through means other than normal Layer 3 routing and is used to direct traffic over a path different from the one that Layer 3 routing would cause it to take.
tunneling—Architecture providing the services necessary to implement any standard point-to-point data encapsulation scheme.
VPN—Virtual Private Network. A secure IP-based network that shares resources on one or more physical networks. A VPN contains geographically dispersed sites that can communicate securely over a shared backbone.
VPNv4—Indicate a VPN-IPv4 prefix. These prefixes are customer VPN addresses, each of which has been made unique by the addition of an 8-byte route distinguisher.
VRF—VPN routing/forwarding instance. A VRF consists of an IP routing table, a derived forwarding table, a set of interfaces that use the forwarding table, and a set of rules and routing protocols that determine what goes into the forwarding table. In general, a VRF includes the routing information that defines a customer VPN site that is attached to a PE router.
