Cisco IOS Software Releases 12.0 ST

Table Of Contents

MPLS VPN Carrier Supporting Carrier

Feature Overview

Providing a Backbone Network to a Customer Carrier Who Is an ISP

Establishing a Route Between the Backbone Carrier and the Customer Carrier Who Is an ISP

Transporting a Packet Through a Network of a Backbone Carrier and Customer Carrier Who Is an ISP

Providing a Backbone Network to a Customer Carrier Who Is a BGP/MPLS VPN Service Provider

Establishing a Route Between the Backbone Carrier and the Customer Carrier Who Is an MPLS VPN Service Provider

Transporting a Packet Through a Network of a Backbone Carrier and Customer Carrier Who Is an MPLS VPN Service Provider

Benefits

Requirements

Related Features and Technologies

Related Documents

Supported Platforms

Supported Standards, MIBs, and RFCs

Prerequisites

Configuration Tasks

Configuring the Backbone Carrier PE Router

Configuring the Customer Carrier CE Routers

Verifying the Carrier Supporting Carrier Configuration

Configuration Examples

Configuring a Carrier Supporting Carrier Network with a Customer Who Is an ISP

CSC-CE1 Configuration

CSC-PE1 Configuration

CSC-PE2 Configuration

CSC-CE2 Configuration

Configuring a Carrier Supporting Carrier Network with a Customer Who Is an MPLS VPN Provider

CE1 Configuration

PE1 Configuration

CSC-CE1 Configuration

CSC-PE1 Configuration

CSC-PE2 Configuration

CSC-CE2 Configuration

PE2 Configuration

CE2 Configuration

Configuring a Carrier Supporting Carrier Network That Contains Route Reflectors

Backbone Carrier Configuration

Customer Carrier Site 1 Configuration

Customer Carrier Site 2 Configuration

Configuring a Carrier Supporting Carrier Network with a Customer Who Has VPNs at the Edge of Their Network

Backbone Carrier Configuration

Customer Carrier Site 1 Configuration

Customer Carrier Site 2 Configuration

Glossary

MPLS VPN Carrier Supporting Carrier

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The carrier supporting carrier feature enables one MPLS VPN-based service provider to allow other service providers to use a segment of its backbone network. This document includes the following sections:

•Feature Overview

•Supported Platforms

•Supported Standards, MIBs, and RFCs

•Prerequisites

•Configuration Tasks

•Configuration Examples

•Glossary

The following table lists the changes made to this document:

Release	Modification
12.0(14)ST	This document was introduced.
12.0(16)ST	Added support for the Cisco 12000 series routers (Engine 0).

Feature Overview

Carrier supporting carrier is a term used to describe a situation where one service provider allows another service provider to use a segment of its backbone network. The service provider that provides the segment of the backbone network to the other provider is called the backbone carrier. The service provider that uses the segment of the backbone network is called the customer carrier.

This feature module focuses on a backbone carrier that offers Border Gateway Protocol and Multiprotocol Label Switching (BGP/MPLS) VPN services. The customer carrier can be either

•An Internet service provider (ISP)

•A BGP/MPLS VPN service provider

This feature module describes both types of customer carrier.

Providing a Backbone Network to a Customer Carrier Who Is an ISP

This section explains how a BGP/MPLS VPN service provider (backbone carrier) can provide a segment of its backbone network to a customer who is an ISP.

Consider the following example and Figure 1:

An ISP has two sites: one in California, the other in Maine. Each site is a point of presence (POP). The ISP wants to connect these sites using a VPN service provided by a backbone carrier. Figure 1 illustrates this situation:

Figure 1 Sample BGP/MPLS Backbone Carrier Supporting an ISP

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Note The CE routers in the figures in this feature module are CE routers to the backbone carrier. However, they are PE routers to the customer carrier.

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Note In this document, the following abbreviations are used, which have the following meanings:

CE router: A customer edge router is part of a customer network and interfaces to a provider edge (PE) router. In this document, the CE router sits on the edge of the customer carrier network.

PE router: A provider edge router is part of a service provider's network connected to a customer edge (CE) router. In this document, the PE routers sits on the edge of the backbone carrier network.

ASBR: In this document, an autonomous system boundary router connects one autonomous system to another.

See the Glossary for the complete definitions of these terms.

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In this example, only the backbone carrier uses MPLS. The customer carrier (ISP) uses only IP. As a result, the backbone carrier must carry all the Internet routes of the customer carrier, which could be as many as 100,000 routes. This poses a scalability problem for the backbone carrier. To solve the scalability problem, the backbone carrier is configured as follows:

•The backbone carrier allows only internal routes of the customer carrier (IGP routes) to be exchanged between the CE routers of the customer carrier and the PE routers of the backbone carrier.

•MPLS is enabled on the interface between the CE router of the customer carrier and the PE router of the backbone carrier.

Internal and external routes are differentiated this way:

•Internal routes go to any of the routers within the ISP.

•External routes go to the Internet.

The number of internal routes is much smaller than the number of external routes. Restricting the routes between the CE routers of the customer carrier and the PE routers of the backbone carrier significantly reduces the number of routes that the PE router needs to maintain.

Since the PE routers do not have to carry external routes in the VRF routing table, they can use the incoming label in the packet to forward the customer carrier Internet traffic. Adding MPLS to the routers provides a consistent method of transporting packets from the customer carrier to the backbone carrier. MPLS allows the exchange of an MPLS label between the PE and the CE routers for every internal customer carrier route. The routers in the customer carrier have all the external routes either through IBGP or route redistribution to provide Internet connectivity. Figure 2 shows how information is exchanged when the network is configured in this manner.

Figure 2 Backbone Carrier Exchanging Routing Information with a Customer Carrier Who Is an ISP

Establishing a Route Between the Backbone Carrier and the Customer Carrier Who Is an ISP

In the example shown in Figure 3, routes are created between the backbone carrier and the customer carrier sites. ASBR2 receives an Internet route that originated outside the network. All routers in the ISP sites have all the external routes through IBGP connections among them.

Figure 3 How a Route Is Established Between a Backbone Carrier and a Customer Carrier Who Is an ISP

Table 1 describes the process of establishing the route, which can be divided into two distinct steps:

•The backbone carrier propagates the IGP information of the customer carrier, which enables the customer carrier routers to reach all the customer carrier routers in the remote sites.

•Once the routers of the customer carriers in different sites are reachable, external routes can be propagated in the customer carrier sites, using IBGP without using the backbone carrier routers.

Table 1 Establishing a Route Between the Backbone Carrier and the Customer Carrier Who Is an ISP

Step 1	CSC-CE2 sends the internal routes within site 2 to CSC-PE2. The routes include the route to ASBR2.
Step 2	CSC-PE2 sends the routing information for site 2 to CSC-PE1, using MPLS VPN processes. CSC-PE1 gets one label (called L3), which is associated with the route to the VPN-IP address for ASBR2. CSC-PE1 gets another label (called L2) that is associated with the route to CSC-PE2.
Step 3	CSC-PE1 sends the routing information associated with internal routes from site 2 to CSC-CE1. CSC-PE1 also sends the label binding information. As a result, CSC-CE1 gets the route to ASBR2 with CSC-PE1 as the next hop. The label associated with that route is called L1.
Step 4	CSC-CE1 distributes the routing information through site 1. Every router in site 1 gets a route for every internal destination in site 2. Therefore, every router in site 1 can reach routers in site 2 and learn external routes through IBGP.
Step 5	ASBR2 receives an Internet route.
Step 6	The IBGP sessions exchange the external routing information of the ISP, including a route to the Internet. Every router in site 1 knows a route to the Internet, with ASBR2 as the next hop of that route.

Transporting a Packet Through a Network of a Backbone Carrier and Customer Carrier Who Is an ISP

Table 2 explains each step in the process of transporting a packet. The following conventions are used in Table 2:

•The D in the Label Stack and Destination Address column represents an address that is outside the network, such as an Internet address.

•The notation X(Y) means "the label distributed by Y, which represents the route to X."

•In the column Label Stack and Destination Address, when a label stack is present, the top label is listed first; the destination address is listed last.

Table 2 How Packets Travel From a Customer Carrier Who Is an ISP Through a BGP/MPLS Backbone Carrier

	The Packet Is Received By	Label Stack and Destination Address	Label Stack Operation	How the Label Was Learned	Next Hop
Step 1	ASBR1	D	None	—	C1
Step 2	C1	D	None	—	CSC-CE1
Step 3	CSC-CE1	D	Move ASBR2(CSC-PE1) onto the stack	LDP	CSC-PE1
Step 4	PE1	ASBR2(CSC-PE1) D	Replace the top label with ASBR2(CSC-PE2) Push the IGP label for CSC-PE2 CSC-PE2(P1)	BGP	P1
Step 5	P1	CSC-PE2(P1) ASBR2(CSC-PE2) D	Replace the top label with CSC-PE2(P2)	LDP	P2
Step 6	P2	CSC-PE2(P2) ASBR2(CSC-PE2) D	Remove a label from the stack	LDP	CSC-PE2
Step 7	CSC-PE2	ASBR2(CSC-CE2) D	Replace the top label from the stack	LDP	CSC-CE2
Step 8	CSC-CE2	D	Remove a label from the stack	—	C2
Step 9	C2	D	None	—	ASBR2
Step 10	ASBR2	D

Providing a Backbone Network to a Customer Carrier Who Is a BGP/MPLS VPN Service Provider

When a backbone carrier and the customer carrier both provide BGP/MPLS VPN services, the method of transporting data is different from when a customer carrier provides only ISP services. The following list highlights those differences.

•When a customer carrier provides BGP/MPLS VPN services, its external routes are VPN-IPv4 routes. When a customer carrier is an ISP, its external routes are IP routes.

•When a customer carrier provides BGP/MPLS VPN services, every site within the customer carrier must use MPLS. When a customer carrier is an ISP, the sites do not need to use MPLS.

Figure 4 shows how information is exchanged when MPLS VPN services reside on all customer carrier sites and on the backbone carrier.

Figure 4 Backbone Carrier Exchanging Information with a Customer Carrier Who Is an MPLS VPN Service Provider

Establishing a Route Between the Backbone Carrier and the Customer Carrier Who Is an MPLS VPN Service Provider

In the example shown in Figure 5, routes are created between the backbone carrier and the customer carrier sites.

Figure 5 How a Route Is Established Between a Backbone Carrier and a Customer Carrier Who Is an MPLS VPN Service Provider

Table 3 describes the process of establishing the route.

Table 3 Establishing a Route Between the Backbone Carrier and Customer Carrier Sites

Step 1	CE2 sends all the internal routes within site 2 to CSC-PE2.
Step 2	CSC-PE2 sends the routing information for site 2 to CSC-PE1, using MPLS VPN processes. CSC-PE1 gets one label (called L3), which is associated with the route to the VPN-IP address for PE2. CSC-PE1 gets another label (called L2) that is associated with the route to CSC-PE2.
Step 3	CSC-PE1 sends the routing information associated with internal routes from site 2 to CSC-CE1. CSC-PE1 also sends the label binding information. As a result, CSC-CE1 gets the route to PE2 with CSC-PE1 as the next hop. The label associated with that route is called L1.
Step 4	CE1 distributes the routing and labelling information through site 1. Every router in site 1 gets a route for every internal destination in site 2. Therefore, PE1 can establish an MP-IBGP session with PE2.
Step 5	CE2 advertises the internal routes of MPLS VPN site 2 to PE2.
Step 6	PE2 allocates labels for all the VPN routes (regular MPLS VPN functionality) and advertises it to PE1, using MP-IBGP.
Step 7	PE1 can forward traffic from VPN site 1 that is destined for VPN site 2.

Transporting a Packet Through a Network of a Backbone Carrier and Customer Carrier Who Is an MPLS VPN Service Provider

Table 4 explains each step in the process of transporting the packet. The following conventions are used in Table 4:

•The D in the Label Stack and Destination Address column represents an address that is outside the network, such as an Internet address.

•The notation X(Y) means "the label distributed by Y, which represents the route to X."

•In the column Label Stack and Destination Address, when a label stack is present, the top label is listed first; the destination address is listed last.

Table 4 How Packets Travel From a Customer Carrier Running BGP/MPLS VPN Service Through a BGP/MPLS Backbone Carrier

	The Packet Is Received By	Label Stack and Destination Address	Label Stack Operation	How the Label Was Learned	Next Hop
Step 1	PE1	D	Move D(PE2) onto the stack Move PE2(C1)onto the stack	BGP LDP	C1
Step 2	C1	PE2(C1) D(PE2) D	Replace the top label with PE2(CSC-CE1)	LDP	CSC-CE1
Step 3	CSC-CE1	PE2(CSC-CE1) D(PE2) D	Replace the top label with PE2(CSC-PE1)	LDP	CSC-PE1
Step 4	CSC-PE1	PE2(CSC-PE1) D(PE2) D	Replace the top label with PE2(CSC-PE2) Move CSC-PE2(P1) onto the stack	BGP	P1
Step 5	P1	CSC-PE2(P1) PE2(CSC-PE2) D(PE2) D	Replace the top label with CSC-PE2(P2)	LDP	P2
Step 6	P2	CSC-PE2(P2) PE2(P2) D(PE2) D	Remove a label from the stack	LDP	CSC-PE2
Step 7	CSC-PE2	PE2(CSC-PE2) D(PE2) D	Replace the top label with PE2(CSC-CE2)	BGP	CSC-CE2
Step 8	CSC-CE2	PE2(CSC-CE2) D(PE2) D	Replace the top label with PE2(C2)	LDP	C2
Step 9	C2	PE2(C2) D(PE2) D	Remove a label from the stack	LDP	PE2
Step 10	PE2	D(PE2) D

Benefits

The MPLS VPN carrier supporting carrier feature provides the benefits listed in the following paragraphs to service providers who are backbone carriers and customer carriers.

Benefits to the Backbone Carrier

Implementing the MPLS VPN carrier supporting carrier feature enables the backbone carrier to realize the following benefits:

•The backbone carrier can accommodate many customer carriers and give them access to its backbone. The backbone carrier does not need to create and maintain separate backbones for its customer carriers. Using one backbone network to support multiple customer carriers simplifies the backbone carrier's VPN operations. The backbone carrier uses a consistent method for managing and maintaining the backbone network. This is also cheaper and more efficient than maintaining separate backbones.

•The MPLS VPN carrier supporting carrier feature is scalable. Carrier supporting carrier can change the VPN to meet changing bandwidth and connectivity needs. The feature can accommodate unplanned growth and changes. The carrier supporting carrier feature enables tens of thousands of VPNs to be set up over the same network, and it allows a service provider to offer both VPN and Internet services.

•The MPLS VPN carrier supporting carrier feature is a flexible solution. The backbone carrier can accommodate many types of customer carriers. The backbone carrier can accept customer carriers who are ISPs or VPN service providers or both. The backbone carrier can accommodate customer carriers that require security and various bandwidths.

Benefits to the Customer Carrier

Implementing the MPLS VPN carrier supporting carrier feature enables the customer carrier to realize the following benefits:

•The MPLS VPN carrier supporting carrier feature removes from the customer carrier the burden of configuring, operating, and maintaining its own backbone. The customer carrier uses the backbone network of a backbone carrier, but the backbone carrier is responsible for network maintenance and operation.

•Customer carriers who use the VPN services provided by the backbone carrier receive the same level of security that Frame Relay or ATM-based VPNs provide. Customer carriers can also use IPsec in their VPNs for a higher level of security; it is completely transparent to the backbone carrier.

•Customer carriers can use any link layer technology (SONET, DSL, Frame Relay, and so on) to connect the CE routers to the PE routers and the PE routers to the P routers. The MPLS VPN carrier supporting carrier feature is link layer independent. The CE routers and PE routers use IP to communicate, and the backbone carrier uses MPLS.

•The customer carrier can use any addressing scheme and still be supported by a backbone carrier. The customer address space and routing information are independent of the address space and routing information of other customer carriers or the backbone provider.

Requirements

The carrier supporting carrier feature includes the following requirements:

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

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

•A routing protocol is required between the PE and CE routers that connect the backbone carrier to the customer carrier. The routing protocol enables the customer carrier to exchange IGP routing information with the backbone carrier. Use the same routing protocol that the customer carrier uses. You can choose RIP, or OSPF as the routing protocol. BGP is not supported

•Label distribution protocol (LDP) is required between the PE and CE routers that connect the backbone carrier to the customer carrier. LDP is also required on the PE to CE interface for VPN routing and forwarding (VRF). LDP is available on Cisco Release 12.0(10)ST or later.

•All PE routers that link the backbone carrier to the customer carrier must run this IOS software image. Other PE routers, CE routers, and P routers do not need to run this software image, but, they must run a version of IOS software that supports MPLS VPNs (Release 12.0(5)T or later).

•Every packet that crosses the backbone carrier must be encapsulated, so that the packet includes MPLS labels. To ensure that the packets are encapsulated, issue the following command on the PE routers that connect to CE routers:

(config-if)# mpls ip 

For more information, see the IOS Command Reference Guide.

The following features are not supported in the carrier supporting carrier feature:

•ATM MPLS

•Carrier supporting carrier traffic engineering

•Carrier supporting carrier class of service (COS)

•RSVP aggregation

•VPN Multicast between the customer carrier and the backbone carrier network

Related Features and Technologies

The carrier supporting carrier feature is used with the VPN capabilities of MPLS. (MPLS VPNs were introduced in Cisco IOS Release 12.0(5)T.)

Related Documents

•MPLS Virtual Private Network Feature Module

•MPLS Virtual Private Network Enhancements Feature Module

•Cisco IOS Release 12.0 Network Protocols Configuration Guide, Part I

•Cisco IOS Release 12.0 Network Protocols Command Reference, Part I

Supported Platforms

The following router platforms are supported on the edge:

•Cisco 7200 series

•Cisco 7500 series

•Cisco 12000 series (Engine 0)

Supported Standards, MIBs, and RFCs

MIBs

No new or modified MIBs are supported by this feature.

RFCs

•RFC 1171, A Border Gateway Protocol 4

•RFC 1164, Application of the Border Gateway Protocol in the Internet

•RFC 2283, Multiprotocol Extensions for BGP-4

•RFC 2547, BGP/MPLS VPNs

Standards

No new or modified standards are supported by this feature.

Prerequisites

The backbone carrier must be properly configured for MPLS VPN operation before the customer carriers can access the backbone network. Refer to the MPLS Virtual Private Network Feature Module and the MPLS Virtual Private Network Enhancements Feature Module.

Configuration Tasks

See the following sections to enable a backbone carrier to share its backbone network with a customer carrier. Each task entry in the list indicates if the task is optional or required.

•Configuring the Backbone Carrier PE Router (required)

•Configuring the Customer Carrier CE Routers (required)

•Verifying the Carrier Supporting Carrier Configuration (optional)

Configuring the Backbone Carrier PE Router

The following steps explain how to configure the backbone carrier PE route that links to the edge router of the customer carrier.

	Command	Purpose
Step 1	Router(config)# mpls label protocol ldp	Sets the default label distribution protocol for all interfaces to be LDP.
Step 2	Router(config-if)# mpls ip	Enables MPLS on the VRF interface

Configuring the Customer Carrier CE Routers

The following steps explain how to configure the CE router on the customer carrier that links to the edge router of the backbone carrier.

	Command	Purpose
Step 1	Router(config)# mpls label protocol ldp	Sets the default label distribution protocol for all interfaces to LDP.
Step 2	Router(config-if)# mpls ip	Enables MPLS on the VRF interface

Verifying the Carrier Supporting Carrier Configuration

The following command helps to verify that the backbone carrier and customer carrier were correctly configured and now the customer carrier ISP sites can act like one VPN.

show mpls ldp discovery vrf vrf-name all

The Local LDP Identifier field shows the LDP identifier for the local label switching router for this session. The Interfaces field displays the interfaces engaging in LDP discovery activity:

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

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

Configuration Examples

This section provides the following configuration examples:

•Configuring a Carrier Supporting Carrier Network with a Customer Who Is an ISP

•Configuring a Carrier Supporting Carrier Network with a Customer Who Is an MPLS VPN Provider

•Configuring a Carrier Supporting Carrier Network That Contains Route Reflectors

•Configuring a Carrier Supporting Carrier Network with a Customer Who Has VPNs at the Edge of Their Network

Configuring a Carrier Supporting Carrier Network with a Customer Who Is an ISP

Figure 6 shows a carrier supporting carrier network configuration where the customer carrier is an ISP. The customer carrier has two sites, each of which is a point of presence (POP). The customer carrier connects these sites using a VPN service provided by the backbone carrier. The backbone carrier uses MPLS. The ISP sites use IP. To enable packet transfer between the ISP sites and the backbone carrier, the CE routers that connect the ISPs to the backbone carrier run MPLS.

Figure 6 Carrier Supporting Carrier Network with a Customer Carrier Who Is an ISP

The following configuration examples show the configuration of each router in the carrier supporting carrier network. OSPF is the protocol used to connect the customer carrier to the backbone carrier

CSC-CE1 Configuration

mpls label protocol ldp

!

interface Loopback0

 ip address 14.14.14.14 255.255.255.255

 no ip directed-broadcast

 no ip route-cache

 no ip mroute-cache

!

interface ATM1/0

 no ip address

 no ip directed-broadcast

 no ip mroute-cache

 atm clock INTERNAL

 atm sonet stm-1

 no atm enable-ilmi-trap

 no atm ilmi-keepalive

!

interface ATM1/0.1 point-to-point

 ip address 46.0.0.2 255.0.0.0

 no ip directed-broadcast

 atm pvc 101 0 51 aal5snap

 no atm enable-ilmi-trap

 mpls label protocol ldp

 mpls ip

!

interface ATM2/0

 no ip address

 no ip directed-broadcast

 no ip mroute-cache

 atm clock INTERNAL

 atm sonet stm-1

 no atm enable-ilmi-trap

 no atm ilmi-keepalive

!

interface ATM2/0.1 point-to-point

 ip address 38.0.0.2 255.0.0.0

 no ip directed-broadcast

 atm pvc 100 0 50 aal5snap

 no atm enable-ilmi-trap

 mpls label protocol ldp

 mpls ip

!

router ospf 200

 log-adjacency-changes

 redistribute connected subnets

 network 14.14.14.14 0.0.0.0 area 200

 network 38.0.0.0 0.255.255.255 area 200

 network 46.0.0.0 0.255.255.255 area 200

CSC-PE1 Configuration

ip cef distributed

!

ip vrf vpn1

 rd 100:0

 route-target export 100:0

 route-target import 100:0

mpls label protocol ldp

no mpls aggregate-statistics

!

interface Loopback0

 ip address 11.11.11.11 255.255.255.255

 no ip directed-broadcast

 no ip route-cache

 no ip mroute-cache

!

interface Loopback100

 ip vrf forwarding vpn1

 ip address 19.19.19.19 255.255.255.255

 no ip directed-broadcast

!

interface ATM1/1/0

 no ip address

 no ip directed-broadcast

 no ip route-cache distributed

 atm clock INTERNAL

 no atm enable-ilmi-trap

 no atm ilmi-keepalive

!

interface ATM1/1/0.1 point-to-point

 ip address 33.0.0.1 255.0.0.0

 no ip directed-broadcast

 atm pvc 100 0 50 aal5snap

 no atm enable-ilmi-trap

 mpls label protocol ldp

 mpls ip

!

interface ATM3/0/0

 no ip address

 no ip directed-broadcast

 no ip route-cache distributed

 atm clock INTERNAL

 atm sonet stm-1

 no atm enable-ilmi-trap

 no atm ilmi-keepalive

!

interface ATM3/0/0.1 point-to-point

 ip vrf forwarding vpn1

 ip address 46.0.0.1 255.0.0.0

 no ip directed-broadcast

 atm pvc 101 0 51 aal5snap

 no atm enable-ilmi-trap

 mpls label protocol ldp

 mpls ip

!

router ospf 100

 log-adjacency-changes

 passive-interface ATM3/0/0.1

 passive-interface Loopback100

 network 11.11.11.11 0.0.0.0 area 100

 network 33.0.0.0 0.255.255.255 area 100

!

router ospf 200 vrf vpn1

 log-adjacency-changes

 redistribute bgp 100 metric-type 1 subnets

 network 19.19.19.19 0.0.0.0 area 200

 network 46.0.0.0 0.255.255.255 area 200

!

router bgp 100

 bgp log-neighbor-changes

 timers bgp 10 30

 neighbor 12.12.12.12 remote-as 100

 neighbor 12.12.12.12 update-source Loopback0

 !

 address-family ipv4

 neighbor 12.12.12.12 activate

 neighbor 12.12.12.12 send-community extended

 no synchronization

 exit-address-family

 !

 address-family vpnv4

 neighbor 12.12.12.12 activate

 neighbor 12.12.12.12 send-community extended

 exit-address-family

 !

 address-family ipv4 vrf vpn1

 redistribute ospf 200 match internal external 1 external 2

 no auto-summary

 no synchronization

 exit-address-family

CSC-PE2 Configuration

ip cef distributed

!

ip vrf vpn1

 rd 100:0

 route-target export 100:0

 route-target import 100:0

mpls label protocol ldp

no mpls aggregate-statistics

!

interface Loopback0

 ip address 12.12.12.12 255.255.255.255

 no ip directed-broadcast

 no ip route-cache

 no ip mroute-cache

!

interface Loopback100

 ip vrf forwarding vpn1

 ip address 20.20.20.20 255.255.255.255

 no ip directed-broadcast

!

interface ATM0/1/0

 no ip address

 no ip directed-broadcast

 no ip route-cache distributed

 no ip mroute-cache

 atm clock INTERNAL

 atm sonet stm-1

 no atm enable-ilmi-trap

 no atm ilmi-keepalive

!

interface ATM0/1/0.1 point-to-point

 ip address 33.0.0.2 255.0.0.0

 no ip directed-broadcast

 atm pvc 100 0 50 aal5snap

 no atm enable-ilmi-trap

 mpls label protocol ldp

 mpls ip

!

interface ATM3/0/0

 no ip address

 no ip directed-broadcast

 no ip route-cache distributed

 no ip mroute-cache

 atm clock INTERNAL

 atm sonet stm-1

 no atm enable-ilmi-trap

 no atm ilmi-keepalive

!

interface ATM3/0/0.1 point-to-point

 ip vrf forwarding vpn1

 ip address 47.0.0.1 255.0.0.0

 no ip directed-broadcast

 atm pvc 100 0 50 aal5snap

 no atm enable-ilmi-trap

 mpls label protocol ldp

 mpls ip

!

router ospf 100

 log-adjacency-changes

 passive-interface ATM3/0/0.1

 passive-interface Loopback100

 network 12.12.12.12 0.0.0.0 area 100

 network 33.0.0.0 0.255.255.255 area 100

!

router ospf 200 vrf vpn1

 log-adjacency-changes

 redistribute bgp 100 metric-type 1 subnets

 network 20.20.20.20 0.0.0.0 area 200

 network 47.0.0.0 0.255.255.255 area 200

!

router bgp 100

 bgp log-neighbor-changes

 timers bgp 10 30

 neighbor 11.11.11.11 remote-as 100

 neighbor 11.11.11.11 update-source Loopback0

 !

 address-family ipv4

 neighbor 11.11.11.11 activate

 neighbor 11.11.11.11 send-community extended

 no synchronization

 exit-address-family

 !

 address-family vpnv4

 neighbor 11.11.11.11 activate

 neighbor 11.11.11.11 send-community extended

 exit-address-family

 !

 address-family ipv4 vrf vpn1

 redistribute ospf 200 match internal external 1 external 2

 no auto-summary

 no synchronization

 exit-address-family

CSC-CE2 Configuration

ip cef

!         

mpls label protocol ldp

!

interface Loopback0

 ip address 16.16.16.16 255.255.255.255

 no ip directed-broadcast

 no ip route-cache

 no ip mroute-cache

!

interface ATM1/0

 no ip address

 no ip directed-broadcast

 no ip mroute-cache

 atm clock INTERNAL

 atm sonet stm-1

 no atm enable-ilmi-trap

 no atm ilmi-keepalive

!

interface ATM1/0.1 point-to-point

 ip address 47.0.0.2 255.0.0.0

 no ip directed-broadcast

 atm pvc 100 0 50 aal5snap

 no atm enable-ilmi-trap

 mpls label protocol ldp

 mpls ip

!

interface ATM5/0

 no ip address

 no ip directed-broadcast

 no ip mroute-cache

 atm clock INTERNAL

 atm sonet stm-1

 no atm enable-ilmi-trap

 no atm ilmi-keepalive

!

interface ATM5/0.1 point-to-point

 ip address 43.0.0.2 255.0.0.0

 no ip directed-broadcast

 atm pvc 100 0 50 aal5snap

 no atm enable-ilmi-trap

 mpls label protocol ldp

 mpls ip

!

router ospf 200

 log-adjacency-changes

 redistribute connected subnets

 network 16.16.16.16 0.0.0.0 area 200

 network 43.0.0.0 0.255.255.255 area 200

 network 47.0.0.0 0.255.255.255 area 200

Configuring a Carrier Supporting Carrier Network with a Customer Who Is an MPLS VPN Provider

Figure 7 shows a carrier supporting carrier network configuration where the customer carrier is an MPLS VPN provider. The customer carrier has two sites. The backbone carrier and the customer carrier use MPLS. The IBGP sessions exchange the external routing information of the ISP.

Figure 7 Carrier Supporting Carrier Network with a Customer Carrier Who Is an MPLS VPN Provider

The following configuration examples show the configuration of each router in the carrier supporting carrier network. OSPF is the protocol used to connect the customer carrier to the backbone carrier

CE1 Configuration

ip cef

!

interface Loopback0

 ip address 17.17.17.17 255.255.255.255

 no ip directed-broadcast

!

interface Ethernet0/1

 ip address 37.0.0.2 255.0.0.0

 no ip directed-broadcast

!

router ospf 300

 log-adjacency-changes

 redistribute bgp 300 subnets

 passive-interface Ethernet0/1

 network 17.17.17.17 0.0.0.0 area 300

!

router bgp 300

 no synchronization

 bgp log-neighbor-changes

 timers bgp 10 30

 redistribute connected

 redistribute ospf 300 match internal external 1 external 2

 neighbor 37.0.0.1 remote-as 200

 neighbor 37.0.0.1 advertisement-interval 5

 no auto-summary

PE1 Configuration

ip cef

!         

ip vrf vpn2

 rd 200:1

 route-target export 200:1

 route-target import 200:1

mpls label protocol ldp

!

interface Loopback0

 ip address 13.13.13.13 255.255.255.255

 no ip directed-broadcast

 no ip route-cache

 no ip mroute-cache

!

interface ATM1/0

 no ip address

 no ip directed-broadcast

 no ip mroute-cache

 atm clock INTERNAL

 atm sonet stm-1

 no atm enable-ilmi-trap

 no atm ilmi-keepalive

!

interface ATM1/0.1 point-to-point

 ip address 38.0.0.1 255.0.0.0

 no ip directed-broadcast

 atm pvc 100 0 50 aal5snap

 no atm enable-ilmi-trap

 mpls label protocol ldp

 mpls ip

!

interface Ethernet3/0

 ip vrf forwarding vpn2

 ip address 37.0.0.1 255.0.0.0

 no ip directed-broadcast

 no ip mroute-cache

!

router ospf 200

 log-adjacency-changes

 redistribute connected subnets

 passive-interface Ethernet3/0

 network 13.13.13.13 0.0.0.0 area 200

 network 38.0.0.0 0.255.255.255 area 200

!

router bgp 200

 no bgp default ipv4-unicast

 bgp log-neighbor-changes

 timers bgp 10 30

 neighbor 15.15.15.15 remote-as 200

 neighbor 15.15.15.15 update-source Loopback0

 !

 address-family ipv4

 neighbor 15.15.15.15 activate

 neighbor 15.15.15.15 send-community extended

 no synchronization

 exit-address-family

 !

 address-family vpnv4

 neighbor 15.15.15.15 activate

 neighbor 15.15.15.15 send-community extended

 exit-address-family

 !        

 address-family ipv4 vrf vpn2

 neighbor 37.0.0.2 remote-as 300

 neighbor 37.0.0.2 activate

 neighbor 37.0.0.2 as-override

 neighbor 37.0.0.2 advertisement-interval 5

 no auto-summary

 no synchronization

 exit-address-family

CSC-CE1 Configuration

mpls label protocol ldp

!

interface Loopback0

 ip address 14.14.14.14 255.255.255.255

 no ip directed-broadcast

 no ip route-cache

 no ip mroute-cache

!

interface ATM1/0

 no ip address

 no ip directed-broadcast

 no ip mroute-cache

 atm clock INTERNAL

 atm sonet stm-1

 no atm enable-ilmi-trap

 no atm ilmi-keepalive

!

interface ATM1/0.1 point-to-point

 ip address 46.0.0.2 255.0.0.0

 no ip directed-broadcast

 atm pvc 101 0 51 aal5snap

 no atm enable-ilmi-trap

 mpls label protocol ldp

 mpls ip

!

interface ATM2/0

 no ip address

 no ip directed-broadcast

 no ip mroute-cache

 atm clock INTERNAL

 atm sonet stm-1

 no atm enable-ilmi-trap

 no atm ilmi-keepalive

!

interface ATM2/0.1 point-to-point

 ip address 38.0.0.2 255.0.0.0

 no ip directed-broadcast

 atm pvc 100 0 50 aal5snap

 no atm enable-ilmi-trap

 mpls label protocol ldp

 mpls ip

!

router ospf 200

 log-adjacency-changes

 redistribute connected subnets

 network 14.14.14.14 0.0.0.0 area 200

 network 38.0.0.0 0.255.255.255 area 200

 network 46.0.0.0 0.255.255.255 area 200

CSC-PE1 Configuration

ip cef distributed

!

ip vrf vpn1

 rd 100:0

 route-target export 100:0

 route-target import 100:0

mpls label protocol ldp

no mpls aggregate-statistics

!

interface Loopback0

 ip address 11.11.11.11 255.255.255.255

 no ip directed-broadcast

 no ip route-cache

 no ip mroute-cache

!

interface Loopback100

 ip vrf forwarding vpn1

 ip address 19.19.19.19 255.255.255.255

 no ip directed-broadcast

!

interface ATM1/1/0

 no ip address

 no ip directed-broadcast

 no ip route-cache distributed

 atm clock INTERNAL

 no atm enable-ilmi-trap

 no atm ilmi-keepalive

!

interface ATM1/1/0.1 point-to-point

 ip address 33.0.0.1 255.0.0.0

 no ip directed-broadcast

 atm pvc 100 0 50 aal5snap

 no atm enable-ilmi-trap

 mpls label protocol ldp

 mpls ip

!

interface ATM3/0/0

 no ip address

 no ip directed-broadcast

 no ip route-cache distributed

 atm clock INTERNAL

 atm sonet stm-1

 no atm enable-ilmi-trap

 no atm ilmi-keepalive

!

interface ATM3/0/0.1 point-to-point

 ip vrf forwarding vpn1

 ip address 46.0.0.1 255.0.0.0

 no ip directed-broadcast

 atm pvc 101 0 51 aal5snap

 no atm enable-ilmi-trap

 mpls label protocol ldp

 mpls ip

!

router ospf 100

 log-adjacency-changes

 passive-interface ATM3/0/0.1

 passive-interface Loopback100

 network 11.11.11.11 0.0.0.0 area 100

 network 33.0.0.0 0.255.255.255 area 100

!

router ospf 200 vrf vpn1

 log-adjacency-changes

 redistribute bgp 100 metric-type 1 subnets

 network 19.19.19.19 0.0.0.0 area 200

 network 46.0.0.0 0.255.255.255 area 200

!

router bgp 100

 bgp log-neighbor-changes

 timers bgp 10 30

 neighbor 12.12.12.12 remote-as 100

 neighbor 12.12.12.12 update-source Loopback0

 !

 address-family ipv4

 neighbor 12.12.12.12 activate

 neighbor 12.12.12.12 send-community extended

 no synchronization

 exit-address-family

 !

 address-family vpnv4

 neighbor 12.12.12.12 activate

 neighbor 12.12.12.12 send-community extended

 exit-address-family

 !

 address-family ipv4 vrf vpn1

 redistribute ospf 200 match internal external 1 external 2

 no auto-summary

 no synchronization

 exit-address-family

CSC-PE2 Configuration

ip cef distributed

!

ip vrf vpn1

 rd 100:0

 route-target export 100:0

 route-target import 100:0

mpls label protocol ldp

no mpls aggregate-statistics

!

interface Loopback0

 ip address 12.12.12.12 255.255.255.255

 no ip directed-broadcast

 no ip route-cache

 no ip mroute-cache

!

interface Loopback100

 ip vrf forwarding vpn1

 ip address 20.20.20.20 255.255.255.255

 no ip directed-broadcast

!

interface ATM0/1/0

 no ip address

 no ip directed-broadcast

 no ip route-cache distributed

 no ip mroute-cache

 atm clock INTERNAL

 atm sonet stm-1

 no atm enable-ilmi-trap

 no atm ilmi-keepalive

!

interface ATM0/1/0.1 point-to-point

 ip address 33.0.0.2 255.0.0.0

 no ip directed-broadcast

 atm pvc 100 0 50 aal5snap

 no atm enable-ilmi-trap

 mpls label protocol ldp

 mpls ip

!

interface ATM3/0/0

 no ip address

 no ip directed-broadcast

 no ip route-cache distributed

 no ip mroute-cache

 atm clock INTERNAL

 atm sonet stm-1

 no atm enable-ilmi-trap

 no atm ilmi-keepalive

!

interface ATM3/0/0.1 point-to-point

 ip vrf forwarding vpn1

 ip address 47.0.0.1 255.0.0.0

 no ip directed-broadcast

 atm pvc 100 0 50 aal5snap

 no atm enable-ilmi-trap

 mpls label protocol ldp

 mpls ip

!

router ospf 100

 log-adjacency-changes

 passive-interface ATM3/0/0.1

 passive-interface Loopback100

 network 12.12.12.12 0.0.0.0 area 100

 network 33.0.0.0 0.255.255.255 area 100

!

router ospf 200 vrf vpn1

 log-adjacency-changes

 redistribute bgp 100 metric-type 1 subnets

 network 20.20.20.20 0.0.0.0 area 200

 network 47.0.0.0 0.255.255.255 area 200

!

router bgp 100

 bgp log-neighbor-changes

 timers bgp 10 30

 neighbor 11.11.11.11 remote-as 100

 neighbor 11.11.11.11 update-source Loopback0

 !

 address-family ipv4

 neighbor 11.11.11.11 activate

 neighbor 11.11.11.11 send-community extended

 no synchronization

 exit-address-family

 !

 address-family vpnv4

 neighbor 11.11.11.11 activate

 neighbor 11.11.11.11 send-community extended

 exit-address-family

 !

 add