Configuring VRF-lite

Virtual Private Networks (VPNs) provide a secure way for customers to share bandwidth over an ISP backbone network. A VPN is a collection of sites sharing a common routing table. A customer site is connected to the service provider network by one or more interfaces, and the service provider associates each interface with a VPN routing table. A VPN routing table is called a VPN routing/forwarding (VRF) table.

With the VRF-lite feature, the Catalyst 4500 series switch supports multiple VPN routing/forwarding instances in customer edge devices. (VRF-lite is also termed multi-VRF CE, or multi-VRF Customer Edge Device). VRF-lite allows a service provider to support two or more VPNs with overlapping IP addresses using one interface.

Note Starting with Cisco IOS Release 12.2(52)SG, the Catalyst 4500 switch supports VRF lite NSF support with routing protocols OSPF/EIGRP/BGP.

Note The switch does not use Multiprotocol Label Switching (MPLS) to support VPNs. For information about MPLS VRF, refer to the Cisco IOS Switching Services Configuration Guide at:

http://www.cisco.com/en/US/docs/ios/mpls/configuration/guide/mp_vpn_ipv4_ipv6_ps6922_TSD_Products_Configuration_Guide_Chapter.html

This chapter includes these topics:

•VRF-lite Overview

•Default VRF-lite Configuration

•VRF-lite Configuration Guidelines

•Configuring VRFs

•Configuring VRF-Aware Services

•Configuring Multicast VRFs

•Configuring a VPN Routing Session

•Configuring BGP PE to CE Routing Sessions

•VRF-lite Configuration Example

•Displaying VRF-lite Status

Note For complete syntax and usage information for the switch commands used in this chapter, first look at the Cisco Catalyst 4500 Series Switch Command Reference and related publications at this location:

http://www.cisco.com/en/US/products//hw/switches/ps4324/index.html

If the command is not found in the Catalyst 4500 Series Switch Command Reference, it will be found in the larger Cisco IOS library. Refer to the Catalyst 4500 Series Switch Cisco IOS Command Reference and related publications at this location:

http://www.cisco.com/en/US/products/ps6350/index.html

VRF-lite Overview

VRF-lite is a feature that enables a service provider to support two or more VPNs, where IP addresses can be overlapped among the VPNs. VRF-lite uses input interfaces to distinguish routes for different VPNs and forms virtual packet-forwarding tables by associating one or more Layer 3 interfaces with each VRF. Interfaces in a VRF can be either physical, such as Ethernet ports, or logical, such as VLAN SVIs, but a Layer 3 interface cannot belong to more than one VRF at any time.

Note VRF-lite interfaces must be Layer 3 interfaces.

VRF-lite includes these devices:

•Customer edge (CE) devices provide customer access to the service provider network over a data link to one or more provider edge routers. The CE device advertises the site's local routes to the provider edge router and learns the remote VPN routes from it. A Catalyst 4500 series switch can be a CE.

•Provider edge (PE) routers exchange routing information with CE devices by using static routing or a routing protocol such as BGP, RIPv1, or RIPv2.

•The PE is only required to maintain VPN routes for those VPNs to which it is directly attached, eliminating the need for the PE to maintain all of the service provider VPN routes. Each PE router maintains a VRF for each of its directly connected sites. Multiple interfaces on a PE router can be associated with a single VRF if all of these sites participate in the same VPN. Each VPN is mapped to a specified VRF. After learning local VPN routes from CEs, a PE router exchanges VPN routing information with other PE routers by using internal BGP (iBPG).

•Provider routers (or core routers) are any routers in the service provider network that do not attach to CE devices.

With VRF-lite, multiple customers can share one CE, and only one physical link is used between the CE and the PE. The shared CE maintains separate VRF tables for each customer and switches or routes packets for each customer based on its own routing table. VRF-lite extends limited PE functionality to a CE device, giving it the ability to maintain separate VRF tables to extend the privacy and security of a VPN to the branch office.

Figure 36-1 shows a configuration where each Catalyst 4500 series switch acts as multiple virtual CEs. Because VRF-lite is a Layer 3 feature, each interface in a VRF must be a Layer 3 interface.

Figure 36-1 Catalyst 4500 Series Switches Acting as Multiple Virtual CEs

This is the packet-forwarding process in a VRF-lite CE-enabled network as shown in Figure 36-1:

•When the CE receives a packet from a VPN, it looks up the routing table based on the input interface. When a route is found, the CE forwards the packet to the PE.

•When the ingress PE receives a packet from the CE, it performs a VRF lookup. When a route is found, the router adds a corresponding MPLS label to the packet and sends it to the MPLS network.

•When an egress PE receives a packet from the network, it strips the label and uses the label to identify the correct VPN routing table. Then the egress PE performs the normal route lookup. When a route is found, it forwards the packet to the correct adjacency.

•When a CE receives a packet from an egress PE, it uses the input interface to look up the correct VPN routing table. If a route is found, the CE forwards the packet within the VPN.

To configure VRF, create a VRF table and specify the Layer 3 interface associated with the VRF. Then configure the routing protocols in the VPN and between the CE and the PE. BGP is the preferred routing protocol used to distribute VPN routing information across the provider's backbone. The VRF-lite network has three major components:

•VPN route target communities—Lists of all other members of a VPN community. You need to configure VPN route targets for each VPN community member.

•Multiprotocol BGP peering of VPN community PE routers—Propagates VRF reachability information to all members of a VPN community. You need to configure BGP peering in all PE routers within a VPN community.

•VPN forwarding—Transports all traffic between all VPN community members across a VPN service-provider network.

Default VRF-lite Configuration

Table 36-1 shows the default VRF configuration.

Table 36-1 Default VRF Configuration 

Feature
Default Setting

VRF

Disabled. No VRFs are defined.

Maps

No import maps, export maps, or route maps are defined.

VRF maximum routes

None.

Forwarding table

The default for an interface is the global routing table.


VRF-lite Configuration Guidelines

Consider these points when configuring VRF in your network:

•A switch with VRF-lite is shared by multiple customers, and all customers have their own routing tables.

•Because customers use different VRF tables, the same IP addresses can be reused. Overlapped IP addresses are allowed in different VPNs.

•VRF-lite lets multiple customers share the same physical link between the PE and the CE. Trunk ports with multiple VLANs separate packets among customers. All customers have their own VLANs.

•VRF-lite does not support all MPLS-VRF functionality: label exchange, LDP adjacency, or labeled packets.

•For the PE router, there is no difference between using VRF-lite or using multiple CEs. In Figure 36-1, multiple virtual Layer 3 interfaces are connected to the VRF-lite device.

•The Catalyst 4500 series switch supports configuring VRF by using physical ports, VLAN SVIs, or a combination of both. The SVIs can be connected through an access port or a trunk port.

•A customer can use multiple VLANs as long as they do not overlap with those of other customers. A customer's VLANs are mapped to a specific routing table ID that is used to identify the appropriate routing tables stored on the switch.

•The Layer 3 TCAM resource is shared between all VRFs. To ensure that any one VRF has sufficient CAM space, use the maximum routes command.

•A Catalyst 4500 series switch using VRF can support one global network and up to 64 VRFs. The total number of routes supported is limited by the size of the TCAM.

•Most routing protocols (BGP, OSPF, EIGRP, RIP and static routing) can be used between the CE and the PE. However, we recommend using external BGP (EBGP) for these reasons:

–BGP does not require multiple algorithms to communicate with multiple CEs.

–BGP is designed for passing routing information between systems run by different administrations.

–BGP makes it easy to pass attributes of the routes to the CE.

•VRF-lite does not support IGRP and ISIS.

•VRF-lite does not affect the packet switching rate.

•Starting with Cisco IOS Release 12.2(50)SG, Multicast and VRF can be configured together on a Layer 3 interface.

•The Catalyst 4500 series switch supports all the PIM protocols (PIM-SM, PIM-DM, PIM-SSM, PIM BiDIR).

•Multicast VRF is supported on Supervisor Engine 6-E and Catalyst 4900M.

•The capability vrf-lite subcommand under router ospf should be used when configuring OSPF as the routing protocol between the PE and the CE.

Configuring VRFs

To configure one or more VRFs, perform this task:

 
Command
Purpose

Step 1  

Switch# configure terminal

Enters global configuration mode.

Step 2  

Switch(config)# ip routing

Enables IP routing.

Step 3  

Switch(config)# ip vrf vrf-name

Names the VRF, and enter VRF configuration mode.

Step 4  

Switch(config-vrf)# rd 
route-distinguisher

Creates a VRF table by specifying a route distinguisher. Enter either an AS number and an arbitrary number (xxx:y) or an IP address and arbitrary number (A.B.C.D:y).

Step 5  

Switch(config-vrf)# route-target 
{export | import | both} 
route-target-ext-community

Creates a list of import, export, or import and export route target communities for the specified VRF. Enter either an AS system number and an arbitrary number (xxx:y) or an IP address and an arbitrary number (A.B.C.D:y).

Note This command is effective only if BGP is running.

Step 6  

Switch(config-vrf)# import map 
route-map

(Optional) Associates a route map with the VRF.

Step 7  

Switch(config-vrf)# interface 
interface-id

Enters interface configuration mode and specify the Layer 3 interface to be associated with the VRF. The interface can be a routed port or SVI.

Step 8  

Switch(config-if)# ip vrf forwarding 
vrf-name

Associates the VRF with the Layer 3 interface.

Step 9  

Switch(config-if)# end

Returns to privileged EXEC mode.

Step 10  

Switch# show ip vrf [brief | detail | 
interfaces] [vrf-name]

Verifies the configuration. Display information about the configured VRFs.

Step 11  

Switch# copy running-config 
startup-config

(Optional) Saves your entries in the configuration file.

Note For complete syntax and usage information for the commands, refer to the switch command reference for this release and the Cisco IOS Switching Services Command Reference for Release 12.2.

Use the no ip vrf vrf-name global configuration command to delete a VRF and to remove all interfaces from it. Use the no ip vrf forwarding interface configuration command to remove an interface from the VRF.

Configuring VRF-Aware Services

IP services can be configured on global interfaces, and these services run within the global routing instance. IP services are enhanced to run on multiple routing instances; they are VRF-aware. Any configured VRF in the system can be specified for a VRF-aware service.

VRF-Aware services are implemented in platform-independent modules. VRF means multiple routing instances in Cisco IOS. Each platform has its own limit on the number of VRFs it supports.

VRF-aware services have the following characteristics:

•The user can ping a host in a user-specified VRF.

•ARP entries are learned in separate VRFs. The user can display Address Resolution Protocol (ARP) entries for specific VRFs.

These services are VRF-Aware:

•ARP

•Ping

•Simple Network Management Protocol (SNMP)

•Unicast Reverse Path Forwarding (uRPF)

•Syslog

•Traceroute

•FTP and TFTP

•Telnet and SSH

•NTP

User Interface for ARP

To configure VRF-aware ARP, follow these steps.

For complete syntax and usage information for the commands, refer to the switch command reference for this release and the Cisco IOS Switching Services Command Reference, Release 12.2.

 
Command
Purpose
  
Switch(config)# arp vrf vrf-name 
ip-address mac-address ARPA

Create a static arp entry in the specified VRF.

  
Switch# show ip arp vrf vrf-name

Displays the ARP table (static and dynamic entries) in the specified VRF.

User Interface for PING

To perform a VRF-aware ping, do the following:

For complete syntax and usage information for the commands, refer to the switch command reference for this release and the Cisco IOS Switching Services Command Reference, Release 12.2.

 
Command
Purpose
  
Switch# ping vrf vrf-name ip-host

Ping an IP host or address in the specified VRF.

User Interface for SNMP

To configure VRF-aware services for SNMP, follow these steps.

For complete syntax and usage information for the commands, refer to the switch command reference for this release and the Cisco IOS Switching Services Command Reference, Release 12.2.

 
Command
Purpose

Step 1  

Switch# configure terminal

Enters global configuration mode.

Step 2  

Switch(config)# snmp-server trap 
authentication vrf

Enables SNMP traps for packets on a VRF.

Step 3  

Switch(config)# snmp-server engineID 
remote host vrf vpn-instance 
engine-id string

Configures a name for the remote SNMP engine on a switch.

Step 4  

Switch(config)# snmp-server host 
host vrf vpn-instance traps 
community

Specifies the recipient of an SNMP trap operation and specify the VRF table to be used for sending SNMP traps.

Step 5  

Switch(config)# snmp-server host 
host vrf vpn-instance informs 
community

Specifies the recipient of an SNMP inform operation and specify the VRF table to be used for sending SNMP informs.

Step 6  

Switch(config)# snmp-server user 
user group remote host vrf vpn- 
instance security model

Adds a user to an SNMP group for a remote host on a VRF for SNMP access.

Step 7  

Switch(config)# end

Returns to privileged EXEC mode.

User Interface for uRPF

You can configure uRPF on an interface assigned to a VRF. Source lookup is performed in the VRF table.

To configure VRF-aware services for uRPF, follow these steps.

For complete syntax and usage information for the commands, refer to the switch command reference for this release and the Cisco IOS Switching Services Command Reference, Release 12.2.

 
Command
Purpose

Step 1  

Switch# configure terminal

Enters global configuration mode.

Step 2  

Switch(config)# interface 
interface-id

Enters interface configuration mode, and specify the Layer 3 interface to configure.

Step 3  

Switch(config-if)# no switchport

Removes the interface from Layer 2 configuration mode if it is a physical interface.

Step 4  

Switch(config-if)# ip vrf forwarding 
vrf-name

Configures VRF on the interface.

Step 5  

Switch(config-if-vrf)# ip address 
ip-address subnet-mask

Enters the IP address for the interface.

Step 6  

Switch(config-if-vrf)# ip verify 
unicast source reachable-via  
rx allow-default

Enables uRPF on the interface.

Step 7  

Switch(config-if-vrf)# end

Returns to privileged EXEC mode.

User Interface for Syslog

To configure VRF-aware services for Syslog, follow these steps

For complete syntax and usage information for the commands, refer to the switch command reference for this release and the Cisco IOS Switching Services Command Reference, Release 12.2.

 
Command
Purpose

Step 1  

Switch# configure terminal

Enters global configuration mode.

Step 2  

Switch(config)# logging on

Enables or temporarily disable logging of storage router event message.

Step 3  

Switch(config)# logging host 
ip-address vrf vrf-name

Specifies the host address of the syslog server where logging messages are to be sent.

Step 4  

Switch(config)# logging buffered 
logging buffered size debugging

Logs messages to an internal buffer.

Step 5  

Switch(config)# logging trap 
debugging

Limits the logging messages sent to the syslog server.

Step 6  

Switch(config)# logging facility 
facility

Sends system logging messages to a logging facility.

Step 7  

Switch(config)# end

Returns to privileged EXEC mode.

User Interface for Traceroute

To configure VRF-aware services for traceroute, perform this task.

For complete syntax and usage information for the commands, refer to the switch command reference for this release and the Cisco IOS Switching Services Command Reference, Release 12.2.

 
Command
Purpose
  
traceroute vrf vrf-name ipaddress

Specifies the name of a VPN VRF in which to find the destination address.

User Interface for FTP and TFTP

So that FTP and TFTP are VRF-aware, you must configure some FTP/TFTP CLIs. For example, if you want to use a VRF table that is attached to an interface, say E1/0, you need to configure the CLI ip [t]ftp source-interface E1/0 to inform [t]ftp to use a specific routing table. In this example, the VRF table is used to look up the destination IP address. These changes are backward-compatible and do not affect existing behavior. That is, you can use the source-interface CLI to send packets out a particular interface even if no VRF is configured on that interface.

To specify the source IP address for FTP connections, use the ip ftp source-interface show mode command. To use the address of the interface where the connection is made, use the no form of this command.

 
Command
Purpose

Step 1  

Switch# configure terminal

Enters global configuration mode.

Step 2  

Switch(config)# ip ftp 
source-interface interface-type 
interface-number

Specifies the source IP address for FTP connections.

Step 3  

Switch(config)# end

Returns to privileged EXEC mode.

To specify the IP address of an interface as the source address for TFTP connections, use the
ip tftp source-interface show mode command. To return to the default, use the no form of this command.

 
Command
Purpose

Step 1  

Switch# configure terminal

Enters global configuration mode.

Step 2  

Switch(config)# ip tftp 
source-interface interface-type 
interface-number

Specifies the source IP address for TFTP connections.

Step 3  

Switch(config)# end

Returns to privileged EXEC mode.

User Interface for Telnet and SSH

To configure VRF-aware Telnet and SSH, follow these steps.

For complete syntax and usage information for the commands, refer to the switch command reference for this release and the Cisco IOS Switching Services Command Reference, Release 12.2.

 
Command
Purpose
  
Switch# telnet <ip-address>/vrf 
vrf-name

Telnet to an ip host or address in the specified VRF.

  
Switch# ssh -l <username> -vrf  
vrf-name ip-host

SSH to an ip host or address in the specified VRF.

User Interface for NTP

To configure VRF-aware NTP, follow these steps.

For complete syntax and usage information for the commands, refer to the switch command reference for this release and the Cisco IOS Switching Services Command Reference, Release 12.2.

 
Command
Purpose
  
Switch# ntp server vrf vrf-name 
ip-host

Configure NTP server in the specified VRF.

  
Switch# ntp peer vrf vrf-name 
ip-host

Configure NTP peer in the specified VRF.

Configuring Multicast VRFs

To configure multicast within a VRF table, follow these steps.

For complete syntax and usage information for the following commands, see the switch command reference for this release and the Cisco IOS Switching Services Command Reference, Release 12.2.

 
Command
Purpose

Step 1  

Switch# configure terminal

Enters global configuration mode.

Step 2  

Switch(config)# ip routing

Enables IP routing.

Step 3  

Switch(config)# ip vrf vrf-name

Names the VRF, and enter VRF configuration mode.

Step 4  

Switch(config-vrf)# ip 
multicast-routing vrf vrf-name

(Optional) Enables global multicast routing for VRF table.

Step 5  

Switch(config-vrf)# rd 
route-distinguisher

Creates a VRF table by specifying a route distinguisher. Enter either an AS number and an arbitrary number (xxx:y) or an IP address and arbitrary number (A.B.C.D:y).

Step 6  

Switch(config-vrf)# route-target 
{export | import | both} 
route-target-ext-community

Creates a list of import, export, or import and export route target communities for the specified VRF. Enter either an AS system number and an arbitrary number (xxx:y) or an IP address and an arbitrary number (A.B.C.D:y).

The route-target-ext-community should be the same as the route-distinguisher entered in Step 4.

Step 7  

Switch(config-vrf)# import map 
route-map

(Optional) Associates a route map with the VRF.

Step 8  

Switch(config-vrf)# interface 
interface-id

Enters interface configuration mode and specifies the Layer 3 interface to be associated with the VRF. The interface can be a routed port or a SVI.

Step 9  

Switch(config-if)# ip vrf forwarding 
vrf-name

Associates the VRF with the Layer 3 interface.

Step 10  

Switch(config-if)# ip address 
ip-address mask

Configures IP address for the Layer 3 interface.

Step 11  

Switch(config-if)# ip pim 
[sparse-dense mode | dense-mode | 
sparse-mode]

Enables PIM on the VRF-associated Layer 3 interface.

Step 12  

Switch(config-if)# end

Returns to privileged EXEC mode.

Step 13  

Switch# show ip vrf [brief | detail | 
interfaces] [vrf-name]

Verifies the configuration. Display information about the configured VRFs.

Step 14  

Switch# copy running-config 
startup-config

(Optional) Saves your entries in the configuration file.

For more information about configuring a multicast within a Multi-VRF CE, see the
Cisco IOS IP Multicast Configuration Guide, Release 12.4.

Use the no ip vrf vrf-name global configuration command to delete a VRF and to remove all interfaces from it. Use the no ip vrf forwarding interface configuration command to remove an interface from the VRF.

Configuring a VPN Routing Session

Routing within the VPN can be configured with any supported routing protocol (RIP, OSPF, or BGP) or with static routing. The configuration shown here is for OSPF, but the process is the same for other protocols.

To configure OSPF in the VPN, perform this task:

 
Command
Purpose

Step 1 

Switch# configure terminal

Enters global configuration mode.

Step 2 

Switch(config)# router ospf process-id vrf vrf-name

Enables OSPF routing, specifies a VPN forwarding table, and enters router configuration mode.

Step 3 

Switch(config-router)# log-adjacency-changes

(Optional) Logs changes in the adjacency state. This is the default state.

Step 4 

Switch(config-router)# redistribute bgp autonomous-system-number subnets

Sets the switch to redistribute information from the BGP network to the OSPF network.

Step 5 

Switch(config-router)# network network-number area area-id

Defines a network address and mask on which OSPF runs and the area ID for that network address.

Step 6 

Switch(config-router)# end

Returns to privileged EXEC mode.

Step 7 

Switch# show ip ospf process-id

Verifies the configuration of the OSPF network.

Step 8 

Switch# copy running-config startup-config

(Optional) Saves your entries in the configuration file.

Use the no router ospf process-id vrf vrf-name global configuration command to disassociate the VPN forwarding table from the OSPF routing process.

Configuring BGP PE to CE Routing Sessions

To configure a BGP PE to CE routing session, perform this task:

 
Command
Purpose

Step 1 

Switch# configure terminal

Enters global configuration mode.

Step 2 

Switch(config)# router bgp autonomous-system-number

Configures the BGP routing process with the AS number passed to other BGP routers and enters router configuration mode.

Step 3 

Switch(config-router)# network network-number mask network-mask

Specifies a network and mask to announce using BGP.

Step 4 

Switch(config-router)# redistribute ospf process-id match internal

Sets the switch to redistribute OSPF internal routes.

Step 5 

Switch(config-router)# network network-number area area-id

Defines a network address and mask on which OSPF runs and the area ID for that network address.

Step 6 

Switch(config-router-af)# address-family ipv4 vrf vrf-name

Defines BGP parameters for PE to CE routing sessions and enters VRF address-family mode.

Step 7 

Switch(config-router-af)# neighbor address remote-as as-number

Defines a BGP session between PE and CE routers.

Step 8 

Switch(config-router-af)# neighbor address activate

Activates the advertisement of the IPv4 address family.

Step 9 

Switch(config-router-af)# end

Returns to privileged EXEC mode.

Step 10 

Switch# show ip bgp [ipv4] [neighbors]

Verifies BGP configuration.

Step 11 

Switch# copy running-config startup-config

(Optional) Saves your entries in the configuration file.

Use the no router bgp autonomous-system-number global configuration command to delete the BGP routing process. Use the command with keywords to delete routing characteristics.

VRF-lite Configuration Example

Figure 36-2 is a simplified example of the physical connections in a network similar to that in Figure 36-1. OSPF is the protocol used in VPN1, VPN2, and the global network. BGP is used in the CE to PE connections. The example commands show how to configure the CE switch S8 and include the VRF configuration for switches S20 and S11 and the PE router commands related to traffic with switch S8. Commands for configuring the other switches are not included but would be similar.

Figure 36-2 VRF-lite Configuration Example

Configuring Switch S8

On switch S8, enable routing and configure VRF. 

Switch# configure terminal 

Enter configuration commands, one per line.  End with CNTL/Z.

Switch(config)# ip routing 

Switch(config)# ip vrf v11

Switch(config-vrf)# rd 800:1

Switch(config-vrf)# route-target export 800:1

Switch(config-vrf)# route-target import 800:1

Switch(config-vrf)# exit

Switch(config)# ip vrf v12

Switch(config-vrf)# rd 800:2

Switch(config-vrf)# route-target export 800:2

Switch(config-vrf)# route-target import 800:2

Switch(config-vrf)# exit

 
   
 
    
   
 Configure the loopback and physical interfaces on switch S8. Fast Ethernet interface 3/5 is a trunk connection to the PE. Interfaces 3/7 and 3/11 connect to VPNs: 
 
    
   
 
    
Switch(config)# interface loopback1

 
   
 
    
   
 
    
Switch(config-if)# ip vrf forwarding v11

 
   
 
    
   
 
    
Switch(config-if)# ip address 8.8.1.8 255.255.255.0

 
   
 
    
   
 
    
Switch(config-if)# exit

 
   
 
    
   
 
    
 
   
 
    
   
 
    
Switch(config)# interface loopback2

 
   
 
    
   
 
    
Switch(config-if)# ip vrf forwarding v12

 
   
 
    
   
 
    
Switch(config-if)# ip address 8.8.2.8 255.255.255.0

 
   
 
    
   
 
    
Switch(config-if)# exit

 
   
 
    
   
 
    
 
   
 
    
   
 
    
Switch(config)# interface FastEthernet3/5

 
   
 
    
   
 
    
Switch(config-if)# switchport trunk encapsulation dot1q

 
   
 
    
   
 
    
Switch(config-if)# switchport mode trunk

 
   
 
    
   
 
    
Switch(config-if)# no ip address

 
   
 
    
   
 
    
Switch(config-if)# exit

 
   
 
    
    
   
 
    
Switch(config)# interface FastEthernet3/8

 
   
 
    
   
 
    
Switch(config-if)# switchport access vlan 208

 
   
 
    
   
 
    
Switch(config-if)# no ip address

 
   
 
    
   
 
    
Switch(config-if)# exit

 
   
 
    
    
   
 
    
Switch(config)# interface FastEthernet3/11

 
   
 
    
   
 
    
Switch(config-if)# switchport trunk encapsulation dot1q

 
   
 
    
   
 
    
Switch(config-if)# switchport mode trunk

 
   
 
    
   
 
    
Switch(config-if)# no ip address

 
   
 
    
   
 
    
Switch(config-if)# exit

 
   
 
    
    
   
 Configure the VLANs used on switch S8. VLAN 10 is used by VRF 11 between the CE and the PE. VLAN 20 is used by VRF 12 between the CE and the PE. VLANs 118 and 208 are used for VRF for the VPNs that include switch S11 and switch S20, respectively: 
 
    
   
 
    
Switch(config)# interface Vlan10

 
   
 
    
   
 
    
Switch(config-if)# ip vrf forwarding v11

 
   
 
    
   
 
    
Switch(config-if)# ip address 38.0.0.8 255.255.255.0

 
   
 
    
   
 
    
Switch(config-if)# exit

 
   
 
    
    
   
 
    
Switch(config)# interface Vlan20

 
   
 
    
   
 
    
Switch(config-if)# ip vrf forwarding v12

 
   
 
    
   
 
    
Switch(config-if)# ip address 83.0.0.8 255.255.255.0

 
   
 
    
   
 
    
Switch(config-if)# exit

 
   
 
    
    
   
 
    
Switch(config)# interface Vlan118

 
   
 
    
   
 
    
Switch(config-if)# ip vrf forwarding v12

 
   
 
    
   
 
    
Switch(config-if)# ip address 118.0.0.8 255.255.255.0

 
   
 
    
   
 
    
Switch(config-if)# exit

 
   
 
    
    
   
 
    
Switch(config)# interface Vlan208

 
   
 
    
   
 
    
Switch(config-if)# ip vrf forwarding v11

 
   
 
    
   
 
    
Switch(config-if)# ip address 208.0.0.8 255.255.255.0

 
   
 
    
   
 
    
Switch(config-if)# exit

 
   
 
    
   
 
    
 
   
 
    
   
 Configure OSPF routing in VPN1 and VPN2: 
 
    
   
 
    
Switch(config)# router ospf 1 vrf vl1

 
   
 
    
   
 
    
Switch(config-router)# redistribute bgp 800 subnets

 
   
 
    
   
 
    
Switch(config-router)# network 208.0.0.0 0.0.0.255 area 0

 
   
 
    
   
 
    
Switch(config-router)# exit 

 
   
 
    
   
 
    
Switch(config)# router ospf 2 vrf vl2

 
   
 
    
   
 
    
Switch(config-router)# redistribute bgp 800 subnets

 
   
 
    
   
 
    
Switch(config-router)# network 118.0.0.0 0.0.0.255 area 0

 
   
 
    
   
 
    
Switch(config-router)# exit 

 
   
 
    
   
 
    
 
   
 
    
   
 Configure BGP for CE to PE routing: 
 
    
   
 
    
Switch(config)# router bgp 800

 
   
 
    
   
 
    
Switch(config-router)# address-family ipv4 vrf vl2

 
   
 
    
   
 
    
Switch(config-router-af)# redistribute ospf 2 match internal

 
   
 
    
   
 
    
Switch(config-router-af)# neighbor 83.0.0.3 remote-as 100

 
   
 
    
   
 
    
Switch(config-router-af)# neighbor 83.0.0.3 activate

 
   
 
    
   
 
    
Switch(config-router-af)# network 8.8.2.0 mask 255.255.255.0

 
   
 
    
   
 
    
Switch(config-router-af)# exit 

 
   
 
    
    
   
 
    
Switch(config-router)# address-family ipv4 vrf vl1

 
   
 
    
   
 
    
Switch(config-router-af)# redistribute ospf 1 match internal

 
   
 
    
   
 
    
Switch(config-router-af)# neighbor 38.0.0.3 remote-as 100

 
   
 
    
   
 
    
Switch(config-router-af)# neighbor 38.0.0.3 activate

 
   
 
    
   
 
    
Switch(config-router-af)# network 8.8.1.0 mask 255.255.255.0

 
   
 
    
   
 
    
Switch(config-router-af)# end 

 
   
 
     
    
   
 Configuring Switch S20 
 
    
   
 Configure S20 to connect to CE: 
 
    
   
 
    
Switch# configure terminal 

 
   
 
    
   
 
    
Enter configuration commands, one per line.  End with CNTL/Z.

 
   
 
    
   
 
    
Switch(config)# ip routing 

 
   
 
    
   
 
    
Switch(config)# interface Fast Ethernet 0/7

 
   
 
    
   
 
    
Switch(config-if)# no switchport

 
   
 
    
   
 
    
Switch(config-if)# ip address 208.0.0.20 255.255.255.0

 
   
 
    
   
 
    
Switch(config-if)# exit

 
   
 
    
   
 
    
 
   
 
    
   
 
    
Switch(config)# router ospf 101

 
   
 
    
   
 
    
Switch(config-router)# network 208.0.0.0 0.0.0.255 area 0

 
   
 
    
   
 
    
Switch(config-router)# end 

 
   
 
     
    
   
 Configuring Switch S11 
 
    
   
 Configure S11 to connect to CE: 
 
    
   
 
    
Switch# configure terminal 

 
   
 
    
   
 
    
Enter configuration commands, one per line.  End with CNTL/Z.

 
   
 
    
   
 
    
Switch(config)# ip routing 

 
   
 
    
   
 
    
Switch(config)# interface Gigabit Ethernet 0/3

 
   
 
    
   
 
    
Switch(config-if)# switchport trunk encapsulation dot1q

 
   
 
    
   
 
    
Switch(config-if)# switchport mode trunk 

 
   
 
    
   
 
    
Switch(config-if)# no ip address

 
   
 
    
   
 
    
Switch(config-if)# exit

 
   
 
    
   
 
    
 
   
 
    
   
 
    
Switch(config)# interface Vlan118

 
   
 
    
   
 
    
Switch(config-if)# ip address 118.0.0.11 255.255.255.0

 
   
 
    
   
 
    
Switch(config-if)# exit

 
   
 
    
   
 
    
 
   
 
    
   
 
    
Switch(config)# router ospf 101

 
   
 
    
   
 
    
Switch(config-router)# network 118.0.0.0 0.0.0.255 area 0

 
   
 
    
   
 
    
Switch(config-router)# end 

 
   
 
     
    
   
 Configuring the PE Switch S3 
 
    
   
 On switch S3 (the router), these commands configure only the connections to switch S8: 
 
    
   
 
    
Router# configure terminal 

 
   
 
    
   
 
    
Enter configuration commands, one per line.  End with CNTL/Z.

 
   
 
    
   
 
    
Router(config)# ip vrf v1

 
   
 
    
   
 
    
Router(config-vrf)# rd 100:1

 
   
 
    
   
 
    
Router(config-vrf)# route-target export 100:1

 
   
 
    
   
 
    
Router(config-vrf)# route-target import 100:1

 
   
 
    
   
 
    
Router(config-vrf)# exit

 
   
 
    
   
 
    
 
   
 
    
   
 
    
Router(config)# ip vrf v2

 
   
 
    
   
 
    
Router(config-vrf)# rd 100:2

 
   
 
    
   
 
    
Router(config-vrf)# route-target export 100:2

 
   
 
    
   
 
    
Router(config-vrf)# route-target import 100:2

 
   
 
    
   
 
    
Router(config-vrf)# exit

 
   
 
    
    
   
 
    
Router(config)# ip cef

 
   
 
    
   
 
    
Router(config)# interface Loopback1

 
   
 
    
   
 
    
Router(config-if)# ip vrf forwarding v1

 
   
 
    
   
 
    
Router(config-if)# ip address 3.3.1.3 255.255.255.0

 
   
 
    
   
 
    
Router(config-if)# exit

 
   
 
    
   
 
    
 
   
 
    
   
 
    
Router(config)# interface Loopback2

 
   
 
    
   
 
    
Router(config-if)# ip vrf forwarding v2

 
   
 
    
   
 
    
Router(config-if)# ip address 3.3.2.3 255.255.255.0

 
   
 
    
   
 
    
Router(config-if)# exit

 
   
 
    
   
 
    
 
   
 
    
   
 
    
Router(config)# interface Fast Ethernet3/0.10

 
   
 
    
   
 
    
Router(config-if)# encapsulation dot1q 10

 
   
 
    
   
 
    
Router(config-if)# ip vrf forwarding v1

 
   
 
    
   
 
    
Router(config-if)# ip address 38.0.0.3 255.255.255.0

 
   
 
    
   
 
    
Router(config-if)# exit

 
   
 
    
   
 
    
 
   
 
    
   
 
    
Router(config)# interface Fast Ethernet3/0.20

 
   
 
    
   
 
    
Router(config-if)# encapsulation dot1q 20

 
   
 
    
   
 
    
Router(config-if)# ip vrf forwarding v2

 
   
 
    
   
 
    
Router(config-if)# ip address 83.0.0.3 255.255.255.0

 
   
 
    
   
 
    
Router(config-if)# exit

 
   
 
    
   
 
    
 
   
 
    
   
 
    
Router(config)# router bgp 100

 
   
 
    
   
 
    
Router(config-router)# address-family ipv4 vrf v2

 
   
 
    
   
 
    
Router(config-router-af)# neighbor 83.0.0.8 remote-as 800

 
   
 
    
   
 
    
Router(config-router-af)# neighbor 83.0.0.8 activate

 
   
 
    
   
 
    
Router(config-router-af)# network 3.3.2.0 mask 255.255.255.0

 
   
 
    
   
 
    
Router(config-router-af)# exit 

 
   
 
    
   
 
    
Router(config-router)# address-family ipv4 vrf vl

 
   
 
    
   
 
    
Router(config-router-af)# neighbor 83.0.0.8 remote-as 800

 
   
 
    
   
 
    
Router(config-router-af)# neighbor 83.0.0.8 activate

 
   
 
    
   
 
    
Router(config-router-af)# network 3.3.1.0 mask 255.255.255.0

 
   
 
    
   
 
    
Router(config-router-af)# end 

 
   
 
     
    
    
   
 Displaying VRF-lite Status 
 
    
    
   
 To display information about VRF-lite configuration and status, perform one of the following tasks: 
 
    
   
 
 
   
 
    
 
      
      
      
 
        
        

          Command 
        
 		 
        
        

          Purpose 
        
 		 
      
 
      
 
       
Switch# show ip protocols vrf vrf-name 
 
       
 Displays routing protocol information associated with a VRF. 
 		 
      
 
      
 
       
Switch# show ip route vrf vrf-name [connected] [protocol [as-number]] [list] [mobile] [odr] [profile] [static] [summary] [supernets-only] 
 
       
 Displays IP routing table information associated with a VRF. 
 		 
      
 
      
 
       
Switch# show ip vrf [brief | detail | interfaces] [vrf-name] 
 
       
 Displays information about the defined VRF instances. 
 		 
      
 
      
 
       
Switch# show ip mroute vrf instance-name <a.b.c.d | active | bidriectional| count | dense| interface | proxy | pruned | sparse | ssm | static | summary> 
 
       
 Displays information about the defined VRF instances. 
 		 
      
 
      
    
 
   
 
   
 
   
 
 
    
   
 This example shows how to display multicast route table information within a VRF instance: 
 
    
   
 
    
Switch# show ip mroute vrf mcast2 234.34.10.18

 
   
 
    
   
 
    
IP Multicast Routing Table

 
   
 
    
   
 
    
Flags: D - Dense, S - Sparse, B - Bidir Group, s - SSM Group, C - Connected,

 
   
 
    
   
 
    
       L - Local, P - Pruned, R - RP-bit set, F - Register flag,

 
   
 
    
   
 
    
       T - SPT-bit set, J - Join SPT, M - MSDP created entry,

 
   
 
    
   
 
    
       X - Proxy Join Timer Running, A - Candidate for MSDP Advertisement,

 
   
 
    
   
 
    
       U - URD, I - Received Source Specific Host Report, 

 
   
 
    
   
 
    
       Z - Multicast Tunnel, z - MDT-data group sender, 

 
   
 
    
   
 
    
       Y - Joined MDT-data group, y - Sending to MDT-data group

 
   
 
    
   
 
    
       V - RD & Vector, v - Vector

 
   
 
    
   
 
    
Outgoing interface flags: H - Hardware switched, A - Assert winner

 
   
 
    
   
 
    
 Timers: Uptime/Expires

 
   
 
    
   
 
    
 Interface state: Interface, Next-Hop or VCD, State/Mode

 
   
 
    
   
 
    
 

 
   
 
    
   
 
    
(*, 234.34.10.18), 13:39:21/00:02:58, RP 1.1.1.1, flags: BC

 
   
 
    
   
 
    
  Bidir-Upstream: Vlan134, RPF nbr 172.16.34.1

 
   
 
    
   
 
    
  Outgoing interface list:

 
   
 
    
   
 
    
    Vlan45, Forward/Sparse-Dense, 00:00:02/00:02:57, H

 
   
 
    
   
 
    
    Vlan134, Bidir-Upstream/Sparse-Dense, 13:35:54/00:00:00, H

 
   
 
   
 
     
   
 
   
 
    
   
 Note For more information about the information in the displays, refer to the Cisco IOS Switching Services Command Reference at: http://www.cisco.com/en/US/docs/ios/ipswitch/command/reference/isw_book.html