mpls: layer 3 vpns configuration guide, cisco ios release 15s · additionalreferences 125...
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MPLS: Layer 3 VPNs Configuration Guide, Cisco IOS Release 15SFirst Published: November 05, 2012
Last Modified: March 29, 2013
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C O N T E N T S
C H A P T E R 1 MPLS Virtual Private Networks 1
Finding Feature Information 1
Prerequisites for MPLS Virtual Private Networks 1
Restrictions for MPLS Virtual Private Networks 2
Information About MPLS Virtual Private Networks 4
MPLS Virtual Private Network Definition 4
How an MPLS Virtual Private Network Works 5
How Virtual Routing and Forwarding Tables Work in an MPLS Virtual Private
Network 5
How VPN Routing Information Is Distributed in an MPLS Virtual Private Network 6
MPLS Forwarding 6
Major Components of an MPLS Virtual Private Network 6
Benefits of an MPLS Virtual Private Network 7
How to Configure MPLS Virtual Private Networks 9
Configuring the Core Network 9
Assessing the Needs of MPLS Virtual Private Network Customers 9
Configuring MPLS in the Core 10
Connecting the MPLS Virtual Private Network Customers 10
Defining VRFs on the PE Devices to Enable Customer Connectivity 10
Configuring VRF Interfaces on PE Devices for Each VPN Customer 12
Configuring Routing Protocols Between the PE and CE Devices 13
Configuring RIPv2 as the Routing Protocol Between the PE and CE Devices 13
Configuring Static Routes Between the PE and CE Devices 15
Verifying the Virtual Private Network Configuration 17
Verifying Connectivity Between MPLS Virtual Private Network Sites 17
Verifying IP Connectivity from CE Device to CE Device Across the MPLS Core 17
Verifying That the Local and Remote CE Devices Are in the PE Routing Table 18
Configuration Examples for MPLS Virtual Private Networks 19
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Example: Configuring an MPLS Virtual Private Network Using RIP 19
Example: Configuring an MPLS Virtual Private Network Using Static Routes 20
Additional References 21
Feature Information for MPLS Virtual Private Networks 22
C H A P T E R 2 Multiprotocol BGP MPLS VPN 23
Finding Feature Information 23
Prerequisites for Multiprotocol BGP MPLS VPN 23
Information About Multiprotocol BGP MPLS VPN 24
MPLS Virtual Private Network Definition 24
How an MPLS Virtual Private Network Works 25
How Virtual Routing and Forwarding Tables Work in an MPLS Virtual Private
Network 25
How VPN Routing Information Is Distributed in an MPLS Virtual Private
Network 26
BGP Distribution of VPN Routing Information 26
Major Components of an MPLS Virtual Private Network 27
How to Configure Multiprotocol BGP MPLS VPN 27
Configuring Multiprotocol BGP Connectivity on the PE Devices and Route Reflectors 27
Troubleshooting Tips 29
Configuring BGP as the Routing Protocol Between the PE and CE Devices 30
Verifying the Virtual Private Network Configuration 31
Verifying Connectivity Between MPLS Virtual Private Network Sites 32
Verifying IP Connectivity from CE Device to CE Device Across the MPLS Core 32
Verifying That the Local and Remote CE Devices Are in the PE Routing Table 32
Configuration Examples for Multiprotocol BGP MPLS VPN 34
Example: Configuring an MPLS Virtual Private Network Using BGP 34
Additional References 35
Feature Information for Multiprotocol BGP MPLS VPN 35
C H A P T E R 3 MPLS VPN OSPF PE and CE Support 37
Finding Feature Information 37
Prerequisites for MPLS VPN OSPF PE and CE Support 37
Information About MPLS VPN OSPF PE and CE Support 38
Overview of MPLS VPN OSPF PE and CE Support 38
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How to Configure MPLS VPN OSPF PE and CE Support 38
Configuring OSPF as the Routing Protocol Between the PE and CE Devices 38
Verifying Connectivity Between MPLS Virtual Private Network Sites 40
Verifying IP Connectivity from CE Device to CE Device Across the MPLS Core 40
Verifying That the Local and Remote CE Devices Are in the PE Routing Table 41
Configuration Examples for MPLS VPN OSPF PE and CE Support 42
Example: Configuring an MPLS VPN Using OSPF 42
Additional References 43
Feature Information for MPLS VPN OSPF PE and CE Support 43
C H A P T E R 4 MPLS VPN Support for EIGRP Between PE and CE 45
Finding Feature Information 45
Prerequisites for MPLS VPN Support for EIGRP Between PE and CE 46
Information About MPLS VPN Support for EIGRP Between PE and CE 46
Overview of MPLS VPN Support for EIGRP Between PE and CE 46
How to Configure MPLS VPN Support for EIGRP Between PE and CE 46
Configuring EIGRP as the Routing Protocol Between the PE and CE Devices 46
Configuring EIGRP Redistribution in the MPLS VPN 49
Verifying Connectivity Between MPLS Virtual Private Network Sites 51
Verifying IP Connectivity from CE Device to CE Device Across the MPLS Core 51
Verifying That the Local and Remote CE Devices Are in the PE Routing Table 52
Configuration Examples for MPLS VPN Support for EIGRP Between PE and CE 53
Example: Configuring an MPLS VPN Using EIGRP 53
Additional References 54
Feature Information for MPLS VPN Support for EIGRP Between PE and CE 54
C H A P T E R 5 IPv6 VPN over MPLS 57
Finding Feature Information 57
Prerequisites for IPv6 VPN over MPLS 58
Restrictions for IPv6 VPN over MPLS 58
Information About IPv6 VPN over MPLS 58
IPv6 VPN over MPLS Overview 58
Addressing Considerations for IPv6 VPN over MPLS 59
Basic IPv6 VPN over MPLS Functionality 59
IPv6 VPN Architecture Overview 59
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IPv6 VPN Next Hop 60
MPLS Forwarding 60
6VPE over GRE Tunnels 61
VRF Concepts 61
IPv6 VPN Scalability 62
Advanced IPv6 MPLS VPN Functionality 62
Internet Access 62
Multiautonomous-System Backbones 63
Carrier Supporting Carriers 64
How to Configure IPv6 VPN over MPLS 65
Configuring a Virtual Routing and Forwarding Instance for IPv6 65
Binding a VRF to an Interface 68
Configuring a Static Route for PE-to-CE Routing 69
Configuring eBGP PE-to-CE Routing Sessions 70
Configuring the IPv6 VPN Address Family for iBGP 71
Configuring Route Reflectors for Improved Scalability 73
Configuring Internet Access 81
Configuring the Internet Gateway 81
Configuring iBGP 6PE Peering to the VPN PE 81
Configuring the Internet Gateway as the Gateway to the Public Domain 83
Configuring eBGP Peering to the Internet 84
Configuring the IPv6 VPN PE 86
Configuring a Default Static Route from the VRF to the Internet Gateway 86
Configuring a Static Route from the Default Table to the VRF 87
Configuring iBGP 6PE Peering to the Internet Gateway 88
Configuring a Multiautonomous-System Backbone for IPv6 VPN 89
Configuring the PE VPN for a Multiautonomous-System Backbone 91
Configuring iBGP IPv6 VPN Peering to a Route Reflector 91
Configuring IPv4 and Label iBGP Peering to a Route Reflector 93
Configuring the Route Reflector for a Multiautonomous-System Backbone 95
Configuring Peering to the PE VPN 95
Configuring the Route Reflector 97
Configuring Peering to the Autonomous System Boundary Router 100
Configuring Peering to Another ISP Route Reflector 101
Configuring the ASBR 103
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Configuring Peering with Router Reflector RR1 103
Configuring Peering with the Other ISP ASBR2 105
Configuring CSC for IPv6 VPN 107
Configuration Examples for IPv6 VPN over MPLS 109
Examples: IPv6 VPN over MPLS Routing 109
Example: BGP IPv6 Activity Summary 109
Example: Dumping the BGP IPv6 Tables 109
Example: Dumping the IPv6 Routing Tables 109
Examples: IPv6 VPN over MPLS Forwarding 110
Example: PE-CE Connectivity 110
Examples: PE Imposition Path 111
Examples: PE Disposition Path 112
Examples: Label Switch Path 112
Examples: IPv6 VPN over MPLS VRF 113
Examples: VRF Information 113
Example: IPv6 VPN Configuration Using IPv4 Next Hop 113
Additional References 114
Feature Information for IPv6 VPN over MPLS 115
Glossary 116
C H A P T E R 6 Assigning an ID Number to an MPLS VPN 119
Finding Feature Information 119
Restrictions for MPLS VPN ID 119
Information About MPLS VPN ID 120
Introduction to MPLS VPN ID 120
Components of the MPLS VPN ID 120
Management Applications That Use MPLS VPN IDs 120
Dynamic Host Configuration Protocol 121
Remote Authentication Dial-In User Service 121
How to Configure an MPLS VPN ID 121
Specifying an MPLS VPN ID 121
Verifying the MPLS VPN ID Configuration 122
Configuration Examples for Assigning an ID Number to an MPLS VPN 124
Example: Specifying an MPLS VPN ID 124
Example: Verifying the MPLS VPN ID Configuration 124
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Additional References 125
Feature Information for MPLS VPN ID 125
C H A P T E R 7 MPLS VPN Half-Duplex VRF 127
Finding Feature Information 127
Prerequisites for MPLS VPN Half-Duplex VRF 127
Restrictions for MPLS VPN Half-Duplex VRF 128
Information About MPLS VPN Half-Duplex VRF 128
MPLS VPN Half-Duplex VRF Overview 128
Upstream and Downstream VRFs 129
Reverse Path Forwarding Check 130
How to Configure MPLS VPN Half-Duplex VRF 130
Configuring the Upstream and Downstream VRFs on the Spoke PE Device 130
Associating a VRF with an Interface 132
Configuring the Downstream VRF for an AAA Server 133
Verifying the MPLS VPN Half-Duplex VRF Configuration 133
Configuration Examples for MPLS VPN Half-Duplex VRF 137
Examples: Configuring the Upstream and Downstream VRFs on the Spoke PE Device 137
Example: Associating a VRF with an Interface 137
Example Configuring MPLS VPN Half-Duplex VRF Using Static CE-PE Routing 138
Example: Configuring MPLS VPN Half-Duplex VRF Using RADIUS Server and Static
CE-PE Routing 139
Example: Configuring MPLS VPN Half-Duplex VRF Using Dynamic CE-PE Routing 140
Additional References 142
Feature Information for MPLS VPN Half-Duplex VRF 142
C H A P T E R 8 MPLS VPN Show Running VRF 145
Finding Feature Information 145
Prerequisites for MPLS VPN Show Running VRF 146
Restrictions for MPLS VPN Show Running VRF 146
Information About MPLS VPN Show Running VRF 146
Configuration Elements Displayed for MPLS VPN Show Running VRF 146
Display of VRF Routing Protocol Configuration 147
Display of Configuration Not Directly Linked to a VRF 147
Additional References 148
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Feature Information for MPLS VPN Show Running VRF 148
Glossary 149
C H A P T E R 9 MPLS VPN VRF CLI for IPv4 and IPv6 VPNs 151
Finding Feature Information 151
Prerequisites for MPLS VPN VRF CLI for IPv4 and IPv6 VPNs 152
Restrictions for MPLS VPN VRF CLI for IPv4 and IPv6 VPNs 152
Information About MPLS VPN VRF CLI for IPv4 and IPv6 VPNs 152
VRF Concepts Similar for IPv4 and IPv6 MPLS VPNs 152
Single-Protocol VRF to Multiprotocol VRF Migration 152
Multiprotocol VRF Configuration Characteristics 153
How to Configure MPLS VPN VRF CLI for IPv4 and IPv6 VPNs 154
Configuring a VRF for IPv4 and IPv6 MPLS VPNs 154
Associating a Multiprotocol VRF with an Interface 157
Verifying the MPLS VPN VRF CLI for IPv4 and IPv6 VPNs Configuration 158
Migrating from a Single-Protocol IPv4-Only VRF to a Multiprotocol VRF Configuration 161
Configuration Examples for MPLS VPN VRF CLI for IPv4 and IPv6 VPNs 163
Example: Multiprotocol VRF Configuration Single Protocol with Noncommon Policies 163
Example: Multiprotocol VRF Configuration Multiprotocol with Noncommon Policies 163
Example: Multiprotocol VRF Configuration Multiprotocol with Common Policies 164
Example: Multiprotocol VRF Configuration Multiprotocol with Common and Noncommon
Policies 164
Examples: Configuring a VRF for IPv4 and IPv6 VPNs 164
Example: Associating a Multiprotocol VRF with an Interface 165
Examples: Migrating from a Single-Protocol IPv4-Only VRF Configuration to aMultiprotocol
VRF Configuration 165
Additional References 166
Feature Information for MPLS VPN VRF CLI for IPv4 and IPv6 VPNs 167
Glossary 169
C H A P T E R 1 0 MPLS VPN BGP Local Convergence 171
Finding Feature Information 171
Prerequisites for MPLS VPN BGP Local Convergence 172
Restrictions for MPLS VPN BGP Local Convergence 172
Information About MPLS VPN BGP Local Convergence 173
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How Link Failures Are Handled with BGP 173
How Links Are Handled with the MPLS VPN BGP Local Convergence Feature 173
How Link Failures Are Detected 174
How to Configure MPLS VPN BGP Local Convergence 175
Configuring MPLS VPN BGP Local Convergence with IPv4 175
Configuring MPLS VPNBGP Local Convergence with IPv6 176
Examples 178
Troubleshooting Tips 178
Configuration Examples for MPLS VPN BGP Local Convergence 179
Examples: MPLS VPN BGP Local Convergence 179
Examples: MPLS VPN BGP Local Convergence for 6VPE 6PE 181
Additional References 184
Feature Information for MPLS VPN BGP Local Convergence 185
C H A P T E R 1 1 MPLS VPN Route Target Rewrite 187
Finding Feature Information 187
Prerequisites for MPLS VPN Route Target Rewrite 188
Restrictions for MPLS VPN Route Target Rewrite 188
Information About MPLS VPN Route Target Rewrite 188
Route Target Replacement Policy 188
Route Maps and Route Target Replacement 190
How to Configure MPLS VPN Route Target Rewrite 190
Configuring a Route Target Replacement Policy 190
Applying the Route Target Replacement Policy 193
Associating Route Maps with Specific BGP Neighbors 194
Refreshing BGP Session to Apply Route Target Replacement Policy 196
Troubleshooting Tips 197
Verifying the Route Target Replacement Policy 197
Troubleshooting Your Route Target Replacement Policy 199
Configuration Examples for MPLS VPN Route Target Rewrite 201
Examples: Configuring Route Target Replacement Policies 201
Examples: Applying Route Target Replacement Policies 202
Examples: Associating Route Maps with Specific BGP Neighbor 202
Example: Refreshing the BGP Session to Apply the Route Target Replacement
Policy 202
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Additional References 203
Feature Information for MPLS VPN Route Target Rewrite 203
Glossary 204
C H A P T E R 1 2 MPLS VPN Per VRF Label 207
Finding Feature Information 207
Prerequisites for MPLS VPN Per VRF Label 207
Restrictions for MPLS VPN Per VRF Label 208
Information About MPLS VPN Per VRF Label 208
MPLS VPN Per VRF Label Functionality 208
How to Configure MPLS VPN Per VRF Label 209
Configuring the Per VRF Label Feature 209
Examples 210
Configuration Examples for MPLS VPN Per VRF Label 211
Example: No Label Mode Default Configuration 211
Example: Mixed Mode with Global Per-Prefix 213
Example: Mixed Mode with Global Per-VRF 214
Additional References 215
Feature Information for MPLS VPN Per VRF Label 216
C H A P T E R 1 3 Multi-VRF Selection Using Policy-Based Routing 219
Finding Feature Information 219
Prerequisites for Multi-VRF Selection Using Policy-Based Routing 220
Restrictions for Multi-VRF Selection Using Policy-Based Routing 220
Information About Multi-VRF Selection Using Policy-Based Routing 220
Policy Routing of VPN Traffic Based on Match Criteria 220
Policy-Based Routing set Commands 221
Policy-routing Packets for VRF Instances 221
Change of Normal Routing and Forwarding Behavior 222
Support of Inherit-VRF Inter-VRF and VRF-to-Global Routing 223
How to Configure Multi-VRF Selection Using Policy-Based Routing 224
Defining the Match Criteria for Multi-VRF Selection Using Policy-Based Routing 224
Configuring Multi-VRF Selection Using Policy-Based Routing with a Standard Access
List 224
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ConfiguringMulti-VRF SelectionUsing Policy-BasedRoutingwith a Named Extended
Access List 225
Configuring Multi-VRF Selection in a Route Map 226
ConfiguringMulti-VRF Selection Using Policy-Based Routing and IP VRF Receive on the
Interface 229
Verifying the Configuration of Multi-VRF Selection Using Policy-Based Routing 230
Configuration Examples for Multi-VRF Selection Using Policy-Based Routing 232
Example: Defining the Match Criteria for Multi-VRF Selection Using Policy-Based
Routing 232
Example: Configuring Multi-VRF Selection in a Route Map 233
Additional References 233
Feature Information for Multi-VRF Selection Using Policy-Based Routing 234
Glossary 236
C H A P T E R 1 4 MPLS VPN VRF Selection Using Policy-Based Routing 237
Finding Feature Information 237
Prerequisites for MPLS VPN VRF Selection Using Policy-Based Routing 238
Restrictions for MPLS VPN VRF Selection Using Policy-Based Routing 238
Information About MPLS VPN VRF Selection Using Policy-Based Routing 238
Introduction to MPLS VPN VRF Selection Using Policy-Based Routing 238
Policy-Based Routing Set Clauses Overview 239
Match Criteria for Policy-Based Routing VRF Selection Based on Packet Length 239
How to Configure MPLS VPN VRF Selection Using Policy-Based Routing 240
Configuring Policy-Based Routing VRF Selection with a Standard Access List 240
Configuring Policy-Based Routing VRF Selection with a Named Access List 241
Configuring Policy-Based Routing VRF Selection in a Route Map 242
Configuring Policy-Based Routing on the Interface 244
Configuring IP VRF Receive on the Interface 245
Verifying the Configuration of the MPLS VPN VRF Selection Using Policy-Based
Routing 246
Configuration Examples for MPLS VPN VRF Selection Using Policy-Based Routing 247
Example: Defining Policy-Based Routing VRF Selection in an Access List 247
Examples: Verifying VRF Selection Using Policy-Based Routing 248
Example: Verifying Match Criteria 248
Example: Verifying Route-Map Configuration 248
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Example: Verifying Policy-Based Routing VRF Selection Policy 249
Additional References 249
Feature Information for MPLS VPN VRF Selection Using Policy-Based Routing 249
C H A P T E R 1 5 VRF Aware System Message Logging 251
Finding Feature Information 251
Prerequisites for VRF Aware System Message Logging 252
Restrictions for VRF Aware System Message Logging 252
Information About VRF Aware System Message Logging 252
VRF Aware System Message Logging Benefit 252
VRF Aware System Message Logging on a Provider Edge Device in an MPLS VPN
Network 252
VRF Aware System Message Logging on a Customer Edge Device with VRF-Lite
Configured 253
Message Levels for Logging Commands 254
How to Configure and Verify VRF Aware System Message Logging 254
Configuring a VRF on a Routing Device 254
Associating a VRF with an Interface 256
Configuring VRF Aware System Message Logging on a Routing Device 258
Verifying VRF Aware System Message Logging Operation 260
Configuration Examples for VRF Aware System Message Logging 261
Example: Configuring a VRF on a Routing Device 261
Example: Associating a VRF with an Interface 262
Examples: Configuring VRF Aware System Message Logging on a Routing Device 262
Additional References 262
Feature Information for VRF Aware System Message Logging 263
Glossary 264
C H A P T E R 1 6 MPLS VPN 6VPE per VRF Label 267
Finding Feature Information 267
Prerequisites for the MPLS VPN 6VPE per VRF Label Feature 268
Restrictions for the MPLS VPN 6VPE per VRF Label Feature 268
Information About the MPLS VPN 6VPE per VRF Label Feature 268
MPLS VPN 6VPE per VRF Label Functionality 268
How to Configure the MPLS VPN 6VPE per VRF Label Feature 269
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Configuring the MPLS VPN 6VPE per VRF Label Feature 269
Examples 270
Troubleshooting Tips 271
Configuration Examples for MPLS VPN 6VPE per VRF Label 271
Examples: 6VPE No Label Mode Default Configuration 271
Additional References 272
Feature Information for MPLS VPN 6VPE per VRF Label 273
C H A P T E R 1 7 Multi-VRF Support 275
Finding Feature Information 275
Prerequisites for Multi-VRF Support 275
Restrictions for Multi-VRF Support 276
Information About Multi-VRF Support 276
How the Multi-VRF Support Feature Works 276
How Packets Are Forwarded in a Network Using the Multi-VRF Support Feature 277
Considerations When Configuring the Multi-VRF Support Feature 278
How to Configure Multi-VRF Support 278
Configuring VRFs 278
Configuring BGP as the Routing Protocol 281
Configuring PE-to-CE MPLS Forwarding and Signaling with BGP 283
Configuring a Routing Protocol Other than BGP 285
Configuring PE-to-CE MPLS Forwarding and Signaling with LDP 286
Configuration Examples for Multi-VRF Support 287
Example: Configuring Multi-VRF Support on the PE Device 288
Example: Configuring Multi-VRF Support on the CE Device 289
Additional References 290
Feature Information for Multi-VRF Support 291
C H A P T E R 1 8 BGP Best External 293
Finding Feature Information 293
Prerequisites for BGP Best External 294
Restrictions for BGP Best External 294
Information About BGP Best External 295
BGP Best External Overview 295
What the Best External Route Means 295
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BGP Best External Feature Operation 295
Configuration Modes for Enabling BGP Best External 296
How to Configure BGP Best External 297
Configuring the BGP Best External Feature 297
Verifying the BGP Best External Feature 299
Configuration Examples for BGP Best External 302
Example: Configuring the BGP Best External Feature 302
Additional References 303
Feature Information for BGP Best External 304
C H A P T E R 1 9 BGP PIC Edge for IP and MPLS-VPN 307
Finding Feature Information 307
Prerequisites for BGP PIC 308
Restrictions for BGP PIC 308
Information About BGP PIC 308
Benefits of the BGP PIC Edge for IP and MPLS-VPN Feature 308
How BGP Converges Under Normal Circumstances 309
How BGP PIC Improves Convergence 309
BGP Fast Reroute's Role in the BGP PIC Feature 310
How a Failure Is Detected 311
How BGP PIC Achieves Subsecond Convergence 311
How BGP PIC Improves Upon the Functionality of MPLS VPN–BGP Local Convergence 312
Configuration Modes for Enabling BGP PIC 312
BGP PIC Scenarios 312
IP PE-CE Link and Node Protection on the CE Side (Dual PEs) 312
IP PE-CE Link and Node Protection on the CE Side (Dual CEs and Dual PE Primary and
Backup Nodes) 313
IP MPLS PE-CE Link Protection for the Primary or Backup-Alternate Path 315
IP MPLS PE-CE Node Protection for Primary or Backup-Alternate Path 316
Cisco Express Forwarding Recursion 317
How to Configure BGP PIC 318
Configuring BGP PIC 318
Configuration Examples for BGP PIC 321
Example: Configuring BGP PIC 321
Example: Displaying Backup Alternate Paths for BGP PIC 322
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Additional References 324
Feature Information for BGP PIC 325
C H A P T E R 2 0 MPLS over GRE 327
Finding Feature Information 327
Prerequisites for MPLS VPN L3VPN over GRE 327
Restrictions for MPLS VPN 3VPN over GRE 328
Information About MPLS VPN L3VPN over GRE 328
Overview of MPLS VPN L3VPN over GRE 328
PE-to-PE Tunneling 328
P-to-PE Tunneling 329
P-to-P Tunneling 329
How to Configure MPLS VPN L3VPN over GRE 330
Configuring the MPLS over GRE Tunnel Interface 330
Configuration Examples for MPLS VPN L3VPN over GRE 332
Example: Configuring a GRE Tunnel That Spans a non-MPLS Network 332
Example: MPLS Configuration with MPLS VPN L3VPN over GRE 332
Additional References 333
Feature Information for MPLS VPN L3VPN over GRE 334
C H A P T E R 2 1 Dynamic Layer 3 VPNs with Multipoint GRE Tunnels 337
Finding Feature Information 337
Prerequisites for Dynamic L3 VPNs with mGRE Tunnels 338
Restrictions for Dynamic L3 VPNs with mGRE Tunnels 338
Information About Dynamic L3 VPNs with mGRE Tunnels 338
Overview of Dynamic L3 VPNs with mGRE Tunnels 338
Layer 3 mGRE Tunnels 338
Interconnecting Provider Edge Devices Within an IP Network 339
Packet Transport Between IP and MPLS Networks 339
BGP Next Hop Verification 340
How to Configure L3 VPN mGRE Tunnels 340
Creating the VRF and mGRE Tunnel 340
Setting Up BGP VPN Exchange 343
Enabling the MPLS VPN over mGRE Tunnels and Configuring an L3VPN Encapsulation
Profile 345
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Defining the Address Space and Specifying Address Resolution for MPLS VPNs over
mGRE 348
What to Do Next 353
Configuration Examples for Dynamic L3 VPNs Support Using mGRE Tunnels 355
Configuring Layer 3 VPN mGRE Tunnels Example 355
Additional References 356
Feature Information for Dynamic L3 VPNs with mGRE Tunnels 358
C H A P T E R 2 2 MPLS VPN 6VPE Support Over IP Tunnels 359
Finding Feature Information 359
Information About MPLS VPN 6VPE Support Over IP Tunnels 359
MPLS Forwarding 359
6VPE over GRE Tunnels 360
Additional References 360
Feature Information for MPLS VPN 6VPE Support Over IP Tunnels 361
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MPLS: Layer 3 VPNs Configuration Guide, Cisco IOS Release 15Sxviii
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C H A P T E R 1MPLS Virtual Private Networks
An MPLS Virtual Private Network (VPN) consists of a set of sites that are interconnected by means of aMultiprotocol Label Switching (MPLS) provider core network. At each customer site, one or more customeredge (CE) devices attach to one or more provider edge (PE) devices. This module explains how to create anMPLS VPN.
• Finding Feature Information, page 1
• Prerequisites for MPLS Virtual Private Networks, page 1
• Restrictions for MPLS Virtual Private Networks, page 2
• Information About MPLS Virtual Private Networks, page 4
• How to Configure MPLS Virtual Private Networks, page 9
• Configuration Examples for MPLS Virtual Private Networks, page 19
• Additional References, page 21
• Feature Information for MPLS Virtual Private Networks, page 22
Finding Feature InformationYour software release may not support all the features documented in this module. For the latest caveats andfeature information, see Bug Search Tool and the release notes for your platform and software release. Tofind information about the features documented in this module, and to see a list of the releases in which eachfeature is supported, see the feature information table at the end of this module.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support.To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Prerequisites for MPLS Virtual Private Networks• Make sure that you have installed Multiprotocol Label Switching (MPLS), Label Distribution Protocol(LDP), and Cisco Express Forwarding in your network.
MPLS: Layer 3 VPNs Configuration Guide, Cisco IOS Release 15S 1
https://tools.cisco.com/bugsearch/searchhttp://www.cisco.com/go/cfn
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• All devices in the core, including the provider edge (PE) devices, must be able to support Cisco ExpressForwarding and MPLS forwarding. See the “Assessing the Needs of the MPLS Virtual Private NetworkCustomers” section.
• Cisco Express Forwarding must be enabled on all devices in the core, including the PE devices. Forinformation about how to determine if Cisco Express Forwarding is enabled, see the “Configuring BasicCisco Express Forwarding” module in the Cisco Express Forwarding Configuration Guide.
Restrictions for MPLS Virtual Private NetworksWhen static routes are configured in aMultiprotocol Label Switching (MPLS) orMPLS virtual private network(VPN) environment, some variations of the ip route and ip route vrf commands are not supported. Thesevariations of the commands are not supported in software releases that support the Tag Forwarding InformationBase (TFIB). The TFIB cannot resolve prefixes when the recursive route over which the prefixes traveldisappears and then reappears. However, the command variations are supported in releases that support theMPLS Forwarding Infrastructure (MFI). For details about the supported releases, see theMultiprotocol LabelSwitching Command Reference. Use the following guidelines when configuring static routes.
Supported Static Routes in an MPLS Environment
The following ip route command is supported when you configure static routes in an MPLS environment:
• ip route destination-prefix mask interface next-hop-address
The following ip route commands are supported when you configure static routes in an MPLS environmentand configure load sharing with static nonrecursive routes and a specific outbound interface:
• ip route destination-prefix mask interface1 next-hop1
• ip route destination-prefix mask interface2 next-hop2
Unsupported Static Routes in an MPLS Environment That Uses the TFIB
The following ip route command is not supported when you configure static routes in anMPLS environment:
• ip route destination-prefix mask next-hop-address
The following ip route command is not supported when you configure static routes in an MPLS environmentand enable load sharing where the next hop can be reached through two paths:
• ip route destination-prefix mask next-hop-address
The following ip route commands are not supported when you configure static routes in anMPLS environmentand enable load sharing where the destination can be reached through two next hops:
• ip route destination-prefix mask next-hop1
• ip route destination-prefix mask next-hop2
Use the interface an next-hop arguments when specifying static routes.
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Supported Static Routes in an MPLS VPN Environment
The following ip route vrf commands are supported when you configure static routes in an MPLS VPNenvironment, and the next hop and interface are in the same VRF:
• ip route vrf vrf-name destination-prefix mask next-hop-address
• ip route vrf vrf-name destination-prefix mask interface next-hop-address
• ip route vrf vrf-name destination-prefix mask interface1 next-hop1
• ip route vrf vrf-name destination-prefix mask interface2 next-hop2
The following ip route vrf commands are supported when you configure static routes in an MPLS VPNenvironment, and the next hop is in the global table in theMPLS cloud in the global routing table. For example,these commands are supported when the next hop is pointing to the Internet gateway.
• ip route vrf vrf-name destination-prefix mask next-hop-address global
• ip route vrf vrf-name destination-prefix mask interface next-hop-address (This command is supportedwhen the next hop and interface are in the core.)
The following ip route commands are supported when you configure static routes in an MPLS VPNenvironment and enable load sharing with static nonrecursive routes and a specific outbound interface:
• ip route destination-prefix mask interface1 next-hop1
• ip route destination-prefix mask interface2 next-hop2
Unsupported Static Routes in an MPLS VPN Environment That Uses the TFIB
The following ip route command is not supported when you configure static routes in an MPLS VPNenvironment, the next hop is in the global table in theMPLS cloud within the core, and you enable load sharingwhere the next hop can be reached through two paths:
• ip route vrf destination-prefix mask next-hop-address global
The following ip route commands are not supported when you configure static routes in an MPLS VPNenvironment, the next hop is in the global table in theMPLS cloud within the core, and you enable load sharingwhere the destination can be reached through two next hops:
• ip route vrf destination-prefix mask next-hop1 global
• ip route vrf destination-prefix mask next-hop2 global
The following ip route vrf commands are not supported when you configure static routes in an MPLS VPNenvironment, and the next hop and interface are in the same VRF:
• ip route vrf vrf-name destination-prefix mask next-hop1 vrf-name destination-prefix mask next-hop1
• ip route vrf vrf-name destination-prefix mask next-hop2
Supported Static Routes in an MPLS VPN Environment Where the Next Hop Resides in the Global Table onthe CE Device
The following ip route vrf command is supported when you configure static routes in an MPLS VPNenvironment, and the next hop is in the global table on the customer edge (CE) side. For example, the following
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command is supported when the destination prefix is the CE device’s loopback address, as in external BorderGateway Protocol (EBGP) multihop cases.
• ip route vrf vrf-name destination-prefix mask interface next-hop-address
The following ip route commands are supported when you configure static routes in an MPLS VPNenvironment, the next hop is in the global table on the CE side, and you enable load sharing with staticnonrecursive routes and a specific outbound interface:
• ip route destination-prefix mask interface1 nexthop1
• ip route destination-prefix mask interface2 nexthop2
Information About MPLS Virtual Private Networks
MPLS Virtual Private Network DefinitionBefore defining a Multiprotocol Label Switching virtual private network (MPLS VPN), you must define aVPN in general. A VPN is:
• An IP-based network delivering private network services over a public infrastructure
• A set of sites that are allowed to communicate with each other privately over the Internet or other publicor private networks
Conventional VPNs are created by configuring a full mesh of tunnels or permanent virtual circuits (PVCs) toall sites in a VPN. This type of VPN is not easy to maintain or expand, because adding a new site requireschanging each edge device in the VPN.
MPLS-based VPNs are created in Layer 3 and are based on the peer model. The peer model enables the serviceprovider and the customer to exchange Layer 3 routing information. The service provider relays the databetween the customer sites without the customer’s involvement.MPLSVPNs are easier to manage and expand than conventional VPNs.When a new site is added to anMPLSVPN, only the service provider’s edge device that provides services to the customer site needs to be updated.The different parts of the MPLS VPN are described as follows:
• Provider (P) device—Device in the core of the provider network. P devices run MPLS switching, anddo not attach VPN labels to routed packets. The MPLS label in each route is assigned by the provideredge (PE) device. VPN labels are used to direct data packets to the correct egress device.
• PE device—Device that attaches the VPN label to incoming packets based on the interface or subinterfaceon which they are received. A PE device attaches directly to a customer edge (CE) device.
• Customer (C) device—Device in the ISP or enterprise network.
• CE device—Edge device on the network of the ISP that connects to the PE device on the network. ACE device must interface with a PE device.
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The figure below shows a basic MPLS VPN.
Figure 1: Basic MPLS VPN Terminology
How an MPLS Virtual Private Network WorksMultiprotocol Label Switching virtual private network (MPLS VPN) functionality is enabled at the edge ofan MPLS network. The provider edge (PE) device performs the following:
• Exchanges routing updates with the customer edge (CE) device.
• Translates the CE routing information into VPNv4 routes.
• Exchanges VPNv4 routes with other PE devices through the Multiprotocol Border Gateway Protocol(MP-BGP).
The following sections describe how MPLS VPN works:
How Virtual Routing and Forwarding Tables Work in an MPLS Virtual Private NetworkEach virtual private network (VPN) is associated with one or more virtual routing and forwarding (VRF)instances. A VRF defines the VPN membership of a customer site attached to a PE device. A VRF consistsof the following components:
• An IP routing table
• A derived Cisco Express Forwarding table
• A set of interfaces that use the forwarding table
• A set of rules and routing protocol parameters that control the information that is included in the routingtable
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A one-to-one relationship does not necessarily exist between customer sites and VPNs. A site can be a memberof multiple VPNs. However, a site can associate with only one VRF. A site’s VRF contains all the routesavailable to the site from the VPNs of which it is a member.
Packet forwarding information is stored in the IP routing table and the Cisco Express Forwarding table foreach VRF. A separate set of routing and Cisco Express Forwarding tables is maintained for each VRF. Thesetables prevent information from being forwarded outside a VPN, and they also prevent packets that are outsidea VPN from being forwarded to a device within the VPN.
How VPN Routing Information Is Distributed in an MPLS Virtual Private NetworkThe distribution of virtual private network (VPN) routing information is controlled through the use of VPNroute target communities, implemented by Border Gateway Protocol (BGP) extended communities. VPNrouting information is distributed as follows:
• When a VPN route that is learned from a customer edge (CE) device is injected into BGP, a list of VPNroute target extended community attributes is associated with it. Typically the list of route targetcommunity extended values is set from an export list of route targets associated with the virtual routingand forwarding (VRF) instance from which the route was learned.
• An import list of route target extended communities is associated with each VRF. The import list definesroute target extended community attributes that a route must have in order for the route to be importedinto the VRF. For example, if the import list for a particular VRF includes route target extendedcommunities A, B, and C, then any VPN route that carries any of those route target extendedcommunities—A, B, or C—is imported into the VRF.
MPLS ForwardingBased on routing information stored in the virtual routing and forwarding (VRF) IP routing table and VRFCisco Express Forwarding table, packets are forwarded to their destination usingMultiprotocol Label Switching(MPLS).
A provider edge (PE) device binds a label to each customer prefix learned from a customer edge (CE) deviceand includes the label in the network reachability information for the prefix that it advertises to other PEdevices. When a PE device forwards a packet received from a CE device across the provider network, it labelsthe packet with the label learned from the destination PE device. When the destination PE device receives thelabeled packet, it pops the label and uses it to direct the packet to the correct CE device. Label forwardingacross the provider backbone is based on either dynamic label switching or traffic engineered paths. A customerdata packet carries two levels of labels when traversing the backbone:
• The top label directs the packet to the correct PE device.
• The second label indicates how that PE device should forward the packet to the CE device.
Major Components of an MPLS Virtual Private NetworkAnMultiprotocol Label Switching (MPLS)-based virtual private network (VPN) has three major components:
• VPN route target communities—A VPN route target community is a list of all members of a VPNcommunity. VPN route targets need to be configured for each VPN community member.
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• Multiprotocol BGP (MP-BGP) peering of VPN community provider edge (PE) devices—MP-BGPpropagates virtual routing and forwarding (VRF) reachability information to all members of a VPNcommunity. MP-BGP peering must be configured on all PE devices within a VPN community.
• MPLS forwarding—MPLS transports all traffic between all VPN community members across a VPNservice-provider network.
A one-to-one relationship does not necessarily exist between customer sites and VPNs. A given site can be amember of multiple VPNs. However, a site can associate with only one VRF. A customer-site VRF containsall the routes available to the site from the VPNs of which it is a member.
Benefits of an MPLS Virtual Private NetworkMultiprotocol Label Switching virtual private networks (MPLS VPNs) allow service providers to deployscalable VPNs and build the foundation to deliver value-added services, such as the following:
Connectionless Service
A significant technical advantage of MPLSVPNs is that they are connectionless. The Internet owes its successto its basic technology, TCP/IP. TCP/IP is built on a packet-based, connectionless network paradigm. Thismeans that no prior action is necessary to establish communication between hosts, making it easy for twoparties to communicate. To establish privacy in a connectionless IP environment, current VPN solutionsimpose a connection-oriented, point-to-point overlay on the network. Even if it runs over a connectionlessnetwork, a VPN cannot take advantage of the ease of connectivity and multiple services available inconnectionless networks. When you create a connectionless VPN, you do not need tunnels and encryptionfor 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. AVPN 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 areseen as private intranets, you may use new IP services such as:
• Multicast
• Quality of service (QoS)
• Telephony support within a VPN
• Centralized services including content and web hosting to a VPN
You can customize several combinations of specialized services for individual customers. For example, aservice that combines IP multicast with a low-latency service class enables video conferencing within anintranet.
Scalability
If you create a VPN using connection-oriented, point-to-point overlays, Frame Relay, or ATM virtualconnections (VCs), the VPN’s key deficiency is scalability. Specifically, connection-oriented VPNs withoutfully meshed connections between customer sites are not optimal. MPLS-based VPNs, instead, use the peermodel and Layer 3 connectionless architecture to leverage a highly scalable VPN solution. The peer model
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requires a customer site to peer with only one provider edge (PE) device as opposed to all other customeredge (CE) devices that are members of the VPN. The connectionless architecture allows the creation of VPNsin 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 devices andthe further partitioning of VPN and Interior Gateway Protocol (IGP) routes between PE devices and provider(P) devices in a core network.
• PE devices must maintain VPN routes for those VPNs who are members.
• P devices do not maintain any VPN routes.
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 notinadvertently go to another VPN.
Security is provided in the following areas:
• At the edge of a provider network, ensuring packets received from a customer are placed on the correctVPN.
• At the backbone, VPN traffic is kept separate. Malicious spoofing (an attempt to gain access to a PEdevice) is nearly impossible because the packets received from customers are IP packets. These IPpackets must be received on a particular interface or subinterface to be uniquely identified with a VPNlabel.
Ease of Creation
To take full advantage of VPNs, customers must be able to easily create new VPNs and user communities.BecauseMPLSVPNs are connectionless, no specific point-to-point connectionmaps or topologies are required.You can add sites to intranets and extranets and form closed user groups. Managing VPNs in this mannerenables membership of any given site in multiple VPNs, maximizing flexibility in building intranets andextranets.
Flexible Addressing
To make a VPN service more accessible, customers of a service provider can design their own addressingplan, independent of addressing plans for other service provider customers. Many customers use privateaddress spaces, as defined in RFC 1918, and do not want to invest the time and expense of converting topublic IP addresses to enable intranet connectivity. MPLS VPNs allow customers to continue to use theirpresent address spaces without network address translation (NAT) by providing a public and private view ofthe address. A NAT is required only if two VPNs with overlapping address spaces want to communicate. Thisenables customers to use their own unregistered private addresses, and communicate freely across a publicIP network.
Integrated QoS Support
QoS is an important requirement for many IP VPN customers. It provides the ability to address two fundamentalVPN requirements:
• Predictable performance and policy implementation
• Support for multiple levels of service in an MPLS VPN
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Network traffic is classified and labeled at the edge of the network before traffic is aggregated according topolicies 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 probabilityor delay.
Straightforward Migration
For service providers to quickly deploy VPN services, use a straightforward migration path. MPLS VPNs areunique 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 CEdevice and no modifications are required to a customer’s intranet.
How to Configure MPLS Virtual Private Networks
Configuring the Core Network
Assessing the Needs of MPLS Virtual Private Network CustomersBefore you configure a Multiprotocol Label Switching virtual private network (MPLS VPN), you need toidentify the core network topology so that it can best serveMPLSVPN customers. Perform this task to identifythe core network topology.
SUMMARY STEPS
1. Identify the size of the network.2. Identify the routing protocols in the core.3. Determine if you need MPLS VPN High Availability support.4. Determine if you need Border Gateway Protocol (BGP) load sharing and redundant paths in the MPLS
VPN core.
DETAILED STEPS
PurposeCommand or Action
Identify the following to determine the number of devices and ports thatyou need:
Identify the size of the network.Step 1
• How many customers do you need to support?
• How many VPNs are needed per customer?
• How many virtual routing and forwarding instances are there foreach VPN?
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PurposeCommand or Action
Determine which routing protocols you need in the core network.Identify the routing protocols in the core.Step 2
MPLSVPNNonstop Forwarding and Graceful Restart are supported onselect devices and Cisco software releases. Contact Cisco Support forthe exact requirements and hardware support.
Determine if you need MPLS VPN HighAvailability support.
Step 3
For configuration steps, see the “Load Sharing MPLS VPN Traffic”feature module in theMPLS Layer 3 VPNs Inter-AS and CSCConfiguration Guide.
Determine if you need Border GatewayProtocol (BGP) load sharing and redundantpaths in the MPLS VPN core.
Step 4
Configuring MPLS in the CoreTo enable Multiprotocol Label Switching (MPLS) on all devices in the core, you must configure either of thefollowing as a label distribution protocol:
• MPLS Label Distribution Protocol (LDP). For configuration information, see the “MPLS LabelDistribution Protocol (LDP)” module in theMPLS Label Distribution Protocol Configuration Guide.
• MPLS Traffic Engineering Resource Reservation Protocol (RSVP). For configuration information, seethe “MPLS Traffic Engineering and Enhancements” module in theMPLS Traffic Engineering PathCalculation and Setup Configuration Guide.
Connecting the MPLS Virtual Private Network Customers
Defining VRFs on the PE Devices to Enable Customer ConnectivityUse this procedure to define a virtual routing and forwarding (VRF) configuration for IPv4. To define a VRFfor IPv4 and IPv6, see the “Configuring a Virtual Routing and Forwarding Instance for IPv6" section in the“IPv6 VPN over MPLS" module in theMPLS Layer 3 VPNs Configuration Guide.
SUMMARY STEPS
1. enable2. configure terminal3. ip vrf vrf-name4. rd route-distinguisher5. route-target {import | export | both} route-target-ext-community6. import map route-map7. exit
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DETAILED STEPS
PurposeCommand or Action
Enables privileged EXEC mode.enableStep 1
Example:
Device> enable
• Enter your password if prompted.
Enters global configuration mode.configure terminal
Example:
Device# configure terminal
Step 2
Defines the virtual private network (VPN) routing instance by assigning avirtual routing and forwarding (VRF) name and enters VRF configurationmode.
ip vrf vrf-name
Example:
Device(config)# ip vrf vpn1
Step 3
• The vrf-name argument is the name assigned to a VRF.
Creates routing and forwarding tables.rd route-distinguisherStep 4
Example:Device(config-vrf)# rd 100:1
• The route-distinguisher argument adds an 8-byte value to an IPv4prefix to create a VPN IPv4 prefix. You can enter a route distinguisher(RD) in either of these formats:
• 16-bit AS number:your 32-bit number, for example, 101:3
• 32-bit IP address:your 16-bit number, for example, 10.0.0.1:1
Creates a route-target extended community for a VRF.route-target {import | export | both}route-target-ext-community
Step 5
• The import keyword imports routing information from the target VPNextended community.
Example:
Device(config-vrf)# route-targetimport 100:1
• The export keyword exports routing information to the target VPNextended community.
• The both keyword imports routing information from and exportsrouting information to the target VPN extended community.
• The route-target-ext-community argument adds the route-targetextended community attributes to the VRF’s list of import, export, orboth route-target extended communities.
(Optional) Configures an import route map for a VRF.import map route-mapStep 6
Example:
Device(config-vrf)# import mapvpn1-route-map
• The route-map argument specifies the route map to be used as animport route map for the VRF.
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PurposeCommand or Action
(Optional) Exits to global configuration mode.exit
Example:
Device(config-vrf)# exit
Step 7
Configuring VRF Interfaces on PE Devices for Each VPN CustomerTo associate a virtual routing and forwarding (VRF) instance with an interface or subinterface on the provideredge (PE) devices, perform this task.
SUMMARY STEPS
1. enable2. configure terminal3. interface type number4. ip vrf forwarding vrf-name5. end
DETAILED STEPS
PurposeCommand or Action
Enables privileged EXEC mode.enableStep 1
Example:
Device> enable
• Enter your password if prompted.
Enters global configuration mode.configure terminal
Example:
Device# configure terminal
Step 2
Specifies the interface to configure and enters interfaceconfiguration mode.
interface type number
Example:
Device(config)# interface FastEthernet1/0/0
Step 3
• The type argument specifies the type of interface to beconfigured.
• The number argument specifies the port, connector, orinterface card number.
Associates a VRF with the specified interface or subinterface.ip vrf forwarding vrf-nameStep 4
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PurposeCommand or Action
Example:
Device(config-if)# ip vrf forwarding vpn1
• The vrf-name argument is the name assigned to a VRF.
(Optional) Exits to privileged EXEC mode.end
Example:
Device(config-if)# end
Step 5
Configuring Routing Protocols Between the PE and CE DevicesConfigure the provider edge (PE) device with the same routing protocol that the customer edge (CE) deviceuses. You can configure the Border Gateway Protocol (BGP), Routing Information Protocol version 2 (RIPv2),or static routes between the PE and CE devices.
Configuring RIPv2 as the Routing Protocol Between the PE and CE Devices
SUMMARY STEPS
1. enable2. configure terminal3. router rip4. version {1 | 2}5. address-family ipv4 [multicast | unicast | vrf vrf-name]6. network ip-address7. redistribute protocol [process-id] {level-1 | level-1-2 | level-2} [as-number] [metric metric-value]
[metric-type type-value] [match {internal | external 1 | external 2}] [tag tag-value] [route-mapmap-tag][subnets]
8. exit-address-family9. end
DETAILED STEPS
PurposeCommand or Action
Enables privileged EXEC mode.enableStep 1
Example:
Device> enable
• Enter your password if prompted.
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PurposeCommand or Action
Enters global configuration mode.configure terminal
Example:
Device# configure terminal
Step 2
Enables the Routing Information Protocol (RIP).router rip
Example:
Device(config)# router rip
Step 3
Specifies RIP version used globally by the device.version {1 | 2}
Example:
Device(config-router)# version 2
Step 4
Specifies the IPv4 address family type and enters addressfamily configuration mode.
address-family ipv4 [multicast | unicast | vrf vrf-name]
Example:
Device(config-router)# address-family ipv4 vrfvpn1
Step 5
• Themulticast keyword specifies IPv4 multicastaddress prefixes.
• The unicast keyword specifies IPv4 unicast addressprefixes.
• The vrf vrf-name keyword and argument specifies thename of the VRF to associate with subsequent IPv4address family configuration mode commands.
Enables RIP on the PE-to-CE link.network ip-address
Example:
Device(config-router-af)# network 192.168.7.0
Step 6
Redistributes routes from one routing domain into anotherrouting domain.
redistribute protocol [process-id] {level-1 | level-1-2| level-2} [as-number] [metric metric-value]
Step 7
[metric-type type-value] [match {internal | external• For the RIPv2 routing protocol, use the redistributebgp as-number command.
1 | external 2}] [tag tag-value] [route-map map-tag][subnets]
Example:
Device(config-router-af)# redistribute bgp 200
Exits address family configuration mode.exit-address-family
Example:
Device(config-router-af)# exit-address-family
Step 8
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PurposeCommand or Action
(Optional) Exits to privileged EXEC mode.end
Example:
Device(config-router)# end
Step 9
Configuring Static Routes Between the PE and CE Devices
SUMMARY STEPS
1. enable2. configure terminal3. ip route vrf vrf-name4. address-family ipv4 [multicast | unicast | vrf vrf-name]5. redistribute protocol [process-id] {level-1 | level-1-2 | level-2} [as-number] [metric metric-value]
[metric-type type-value] [match {internal | external 1 | external 2}] [tag tag-value] [route-mapmap-tag][subnets]
6. redistribute protocol [process-id] {level-1 | level-1-2 | level-2} [as-number] [metric metric-value][metric-type type-value] [match {internal | external 1 | external 2}] [tag tag-value] [route-mapmap-tag][subnets]
7. exit-address-family8. end
DETAILED STEPS
PurposeCommand or Action
Enables privileged EXEC mode.enableStep 1
Example:
Device> enable
• Enter your password if prompted.
Enters global configuration mode.configure terminal
Example:
Device# configure terminal
Step 2
Defines static route parameters for every provideredge-to-customer edge (PE-to-CE) session and enters routerconfiguration mode.
ip route vrf vrf-name
Example:
Device(config)# ip route vrf 200
Step 3
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PurposeCommand or Action
Specifies the IPv4 address family type and enters address familyconfiguration mode.
address-family ipv4 [multicast | unicast | vrfvrf-name]
Step 4
Example:
Device(config-router)# address-family ipv4 vrfvpn1
• Themulticast keyword specifies IPv4 multicast addressprefixes.
• The unicast keyword specifies IPv4 unicast addressprefixes.
• The vrf vrf-name keyword and argument specify the nameof the VRF to associate with subsequent IPv4 addressfamily configuration mode commands.
Redistributes routes from one routing domain into anotherrouting domain.
redistribute protocol [process-id] {level-1 | level-1-2| level-2} [as-number] [metric metric-value]
Step 5
[metric-type type-value] [match {internal | external• To redistribute virtual routing and forwarding (VRF) staticroutes into the VRFBorder Gateway Protocol (BGP) table,use the redistribute static command.
1 | external 2}] [tag tag-value] [route-map map-tag][subnets]
Example:
Device(config-router-af)# redistribute static
See the command reference page for information about otherarguments and keywords.
Redistributes routes from one routing domain into anotherrouting domain.
redistribute protocol [process-id] {level-1 | level-1-2| level-2} [as-number] [metric metric-value]
Step 6
[metric-type type-value] [match {internal | external• To redistribute directly connected networks into the VRFBGP table, use the redistribute connected command.
1 | external 2}] [tag tag-value] [route-map map-tag][subnets]
Example:
Device(config-router-af)# redistributeconnected
Exits address family configuration mode.exit-address-family
Example:
Device(config-router-af)# exit-address-family
Step 7
(Optional) Exits to privileged EXEC mode.end
Example:
Device(config-router)# end
Step 8
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Verifying the Virtual Private Network ConfigurationA route distinguisher must be configured for the virtual routing and forwarding (VRF) instance, andMultiprotocol Label Switching (MPLS) must be configured on the interfaces that carry the VRF. Use theshow ip vrf command to verify the route distinguisher (RD) and interface that are configured for the VRF.
SUMMARY STEPS
1. show ip vrf
DETAILED STEPS
show ip vrfDisplays the set of defined VRF instances and associated interfaces. The output also maps the VRF instances to theconfigured route distinguisher.
Verifying Connectivity Between MPLS Virtual Private Network SitesTo verify that the local and remote customer edge (CE) devices can communicate across the MultiprotocolLabel Switching (MPLS) core, perform the following tasks:
Verifying IP Connectivity from CE Device to CE Device Across the MPLS Core
SUMMARY STEPS
1. enable2. ping [protocol] {host-name | system-address}3. trace [protocol] [destination]4. show ip route [ip-address [mask] [longer-prefixes]] | protocol [process-id]] | [list [access-list-name |
access-list-number]
DETAILED STEPS
Step 1 enableEnables privileged EXEC mode.
Step 2 ping [protocol] {host-name | system-address}Diagnoses basic network connectivity on AppleTalk, Connectionless-mode Network Service (CLNS), IP, Novell, Apollo,Virtual IntegratedNetwork Service (VINES), DECnet, or XeroxNetwork Service (XNS) networks. Use the ping commandto verify the connectivity from one CE device to another.
Step 3 trace [protocol] [destination]
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Discovers the routes that packets take when traveling to their destination. The trace command can help isolate a troublespot if two devices cannot communicate.
Step 4 show ip route [ip-address [mask] [longer-prefixes]] | protocol [process-id]] | [list [access-list-name | access-list-number]Displays the current state of the routing table. Use the ip-address argument to verify that CE1 has a route to CE2. Verifythe routes learned by CE1. Make sure that the route for CE2 is listed.
Verifying That the Local and Remote CE Devices Are in the PE Routing Table
SUMMARY STEPS
1. enable2. show ip route vrf vrf-name [prefix]3. show ip cef vrf vrf-name [ip-prefix]
DETAILED STEPS
Step 1 enableEnables privileged EXEC mode.
Step 2 show ip route vrf vrf-name [prefix]Displays the IP routing table associated with a virtual routing and forwarding (VRF) instance. Check that the loopbackaddresses of the local and remote customer edge (CE) devices are in the routing table of the provider edge (PE) devices.
Step 3 show ip cef vrf vrf-name [ip-prefix]Displays the Cisco Express Forwarding forwarding table associated with a VRF. Check that the prefix of the remote CEdevice is in the Cisco Express Forwarding table.
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Configuration Examples for MPLS Virtual Private Networks
Example: Configuring an MPLS Virtual Private Network Using RIPCE ConfigurationPE Configuration
ip cefmpls ldp router-id Loopback0 forcempls label protocol ldp!interface Loopback0ip address 10.0.0.9 255.255.255.255
!interface FastEthernet0/0/0ip address 192.0.2.1 255.255.255.0no cdp enable
router ripversion 2timers basic 30 60 60 120redistribute connectednetwork 10.0.0.0network 192.0.2.0no auto-summary
ip vrf vpn1rd 100:1route-target export 100:1route-target import 100:1!ip cefmpls ldp router-id Loopback0 forcempls label protocol ldp!interface Loopback0ip address 10.0.0.1 255.255.255.255!interface FastEthernet0/0/0ip vrf forwarding vpn1ip address 192.0.2.3 255.255.255.0no cdp enableinterface FastEthernet1/1/0ip address 192.0.2.2 255.255.255.0mpls label protocol ldpmpls ip!router ripversion 2timers basic 30 60 60 120!address-family ipv4 vrf vpn1version 2redistribute bgp 100 metric transparentnetwork 192.0.2.0distribute-list 20 inno auto-summaryexit-address-family!router bgp 100no synchronizationbgp log-neighbor changesneighbor 10.0.0.3 remote-as 100neighbor 10.0.0.3 update-source Loopback0no auto-summary!address-family vpnv4neighbor 10.0.0.3 activateneighbor 10.0.0.3 send-community extendedbgp scan-time import 5exit-address-family!address-family ipv4 vrf vpn1redistribute connectedredistribute ripno auto-summaryno synchronizationexit-address-family
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Example: Configuring an MPLS Virtual Private Network Using Static RoutesCE ConfigurationPE Configuration
ip cef!interface Loopback0ip address 10.0.0.9 255.255.255.255!interface FastEthernet0/0/0ip address 192.0.2.2 255.255.0.0no cdp enable!ip route 10.0.0.9 255.255.255.255 192.0.2.33ip route 198.51.100.0 255.255.255.0 192.0.2.33
ip vrf vpn1rd 100:1route-target export 100:1route-target import 100:1
!ip cefmpls ldp router-id Loopback0 forcempls label protocol ldp!interface Loopback0ip address 10.0.0.1 255.255.255.255
!interface FastEthernet0/0/0ip vrf forwarding vpn1ip address 192.0.2.3 255.255.255.0no cdp enable
!interface FastEthernet1/1/0ip address 192.168.0.1 255.255.0.0mpls label protocol ldpmpls ip!router ospf 100network 10.0.0. 0.0.0.0 area 100network 192.168.0.0 255.255.0.0 area 100!router bgp 100no synchronizationbgp log-neighbor changesneighbor 10.0.0.3 remote-as 100neighbor 10.0.0.3 update-source Loopback0
no auto-summary!
address-family vpnv4neighbor 10.0.0.3 activateneighbor 10.0.0.3 send-community extendedbgp scan-time import 5exit-address-family!
address-family ipv4 vrf vpn1redistribute connectedredistribute staticno auto-summaryno synchronizationexit-address-family
!ip route vrf vpn1 10.0.0.9 255.255.255.255192.0.2.2ip route vrf vpn1 192.0.2.0 255.255.0.0192.0.2.2
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Additional ReferencesRelated Documents
Document TitleRelated Topic
Cisco IOS Master Command List, All ReleasesCisco IOS commands
Cisco IOSMultiprotocol Label Switching CommandReference
Description of commands associated withMPLS andMPLS applications
“Configuring Basic Cisco Express Forwarding”module in the Cisco Express ForwardingConfiguration Guide
Configuring Cisco Express Forwarding
“Load Sharing MPLS VPN Traffic” module in theMPLS Layer 3 VPNs Inter-AS and CSCConfigurationGuide
Border Gateway Protocol (BGP) load sharing
“MPLS Label Distribution Protocol (LDP)” modulein theMPLS Label Distribution ProtocolConfiguration Guide
Configuring LDP
“"MPLS Traffic Engineering and Enhancements”module in theMPLS Traffic Engineering PathCalculation and Setup Configuration Guide
Configuring MPLS Traffic Engineering ResourceReservation Protocol (RSVP)
“IPv6 VPN over MPLS” module in theMPLS Layer3 VPNs Configuration Guide
IPv6 VPN over MPLS
Technical Assistance
LinkDescription
http://www.cisco.com/cisco/web/support/index.htmlThe Cisco Support and Documentation websiteprovides online resources to download documentation,software, and tools. Use these resources to install andconfigure the software and to troubleshoot and resolvetechnical issues with Cisco products and technologies.Access to most tools on the Cisco Support andDocumentation website requires a Cisco.com user IDand password.
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MPLS Virtual Private NetworksAdditional References
http://www.cisco.com/en/US/docs/ios/mcl/allreleasemcl/all_book.htmlhttp://www.cisco.com/en/US/docs/ios-xml/ios/mpls/command/mp-cr-book.htmlhttp://www.cisco.com/en/US/docs/ios-xml/ios/mpls/command/mp-cr-book.htmlhttp://www.cisco.com/support
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Feature Information for MPLS Virtual Private NetworksThe following table provides release information about the feature or features described in this module. Thistable lists only the software release that introduced support for a given feature in a given software releasetrain. Unless noted otherwise, subsequent releases of that software release train also support that feature.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support.To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Table 1: Feature Information for MPLS Virtual Private Networks
Feature InformationReleasesFeature Name
The MPLS Virtual PrivateNetworks feature allows a set ofsites that to be interconnected bymeans of a Multiprotocol LabelSwitching (MPLS) provider corenetwork. At each customer site, oneor more customer edge (CE)devices attach to one or moreprovider edge (PE) devices.
In Cisco IOS Release 15.4(1)S,support was added for the CiscoASR 901S Router.
12.0(5)T
12.0(11)ST
12.0(21)ST
12.0(22)S
12.1(5)T
12.2(8)T
12.2(17b)SXA
12.2(27)SBB
12.3(2)T
15.4(1)S
MPLS Virtual Private Networks
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MPLS Virtual Private NetworksFeature Information for MPLS Virtual Private Networks
http://www.cisco.com/go/cfn
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C H A P T E R 2Multiprotocol BGP MPLS VPN
A Multiprotocol Label Switching (MPLS) virtual private network (VPN) consists of a set of sites that areinterconnected by means of an MPLS provider core network. At each site, there are one or more customeredge (CE) devices, which attach to one or more provider edge (PE) devices. PEs use theMultiprotocol-BorderGateway Protocol (MP-BGP) to dynamically communicate with each other.
• Finding Feature Information, page 23
• Prerequisites for Multiprotocol BGP MPLS VPN, page 23
• Information About Multiprotocol BGP MPLS VPN, page 24
• How to Configure Multiprotocol BGP MPLS VPN, page 27
• Configuration Examples for Multiprotocol BGP MPLS VPN, page 34
• Additional References, page 35
• Feature Information for Multiprotocol BGP MPLS VPN, page 35
Finding Feature InformationYour software release may not support all the features documented in this module. For the latest caveats andfeature information, see Bug Search Tool and the release notes for your platform and software release. Tofind information about the features documented in this module, and to see a list of the releases in which eachfeature is supported, see the feature information table at the end of this module.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support.To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Prerequisites for Multiprotocol BGP MPLS VPNConfigure MPLS virtual private networks (VPNs) in the core.
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https://tools.cisco.com/bugsearch/searchhttp://www.cisco.com/go/cfn
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Information About Multiprotocol BGP MPLS VPN
MPLS Virtual Private Network DefinitionBefore defining a Multiprotocol Label Switching virtual private network (MPLS VPN), you must define aVPN in general. A VPN is:
• An IP-based network delivering private network services over a public infrastructure
• A set of sites that are allowed to communicate with each other privately over the Internet or other publicor private networks
Conventional VPNs are created by configuring a full mesh of tunnels or permanent virtual circuits (PVCs) toall sites in a VPN. This type of VPN is not easy to maintain or expand, because adding a new site requireschanging each edge device in the VPN.
MPLS-based VPNs are created in Layer 3 and are based on the peer model. The peer model enables the serviceprovider and the customer to exchange Layer 3 routing information. The service provider relays the databetween the customer sites without the customer’s involvement.MPLSVPNs are easier to manage and expand than conventional VPNs.When a new site is added to anMPLSVPN, only the service provider’s edge device that provides services to the customer site needs to be updated.The different parts of the MPLS VPN are described as follows:
• Provider (P) device—Device in the core of the provider network. P devices run MPLS switching, anddo not attach VPN labels to routed packets. The MPLS label in each route is assigned by the provideredge (PE) device. VPN labels are used to direct data packets to the correct egress device.
• PE device—Device that attaches the VPN label to incoming packets based on the interface or subinterfaceon which they are received. A PE device attaches directly to a customer edge (CE) device.
• Customer (C) device—Device in the ISP or enterprise network.
• CE device—Edge device on the network of the ISP that connects to the PE device on the network. ACE device must interface with a PE device.
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Multiprotocol BGP MPLS VPNInformation About Multiprotocol BGP MPLS VPN
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The figure below shows a basic MPLS VPN.
Figure 2: Basic MPLS VPN Terminology
How an MPLS Virtual Private Network WorksMultiprotocol Label Switching virtual private network (MPLS VPN) functionality is enabled at the edge ofan MPLS network. The provider edge (PE) device performs the following:
• Exchanges routing updates with the customer edge (CE) device.
• Translates the CE routing information into VPNv4 routes.
• Exchanges VPNv4 routes with other PE devices through the Multiprotocol Border Gateway Protocol(MP-BGP).
The following sections describe how MPLS VPN works:
How Virtual Routing and Forwarding Tables Work in an MPLS Virtual Private NetworkEach virtual private network (VPN) is associated with one or more virtual routing and forwarding (VRF)instances. A VRF defines the VPN membership of a customer site attached to a PE device. A VRF consistsof the following components:
• An IP routing table
• A derived Cisco Express Forwarding table
• A set of interfaces that use the forwarding table
• A set of rules and routing protocol parameters that control the information that is included in the routingtable
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Multiprotocol BGP MPLS VPNHow an MPLS Virtual Private Network Works
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A one-to-one relationship does not necessarily exist between customer sites and VPNs. A site can be a memberof multiple VPNs. However, a site can associate with only one VRF. A site’s VRF contains all the routesavailable to the site from the VPNs of which it is a member.
Packet forwarding information is stored in the IP routing table and the Cisco Express Forwarding table foreach VRF. A separate set of routing and Cisco Express Forwarding tables is maintained for each VRF. Thesetables prevent information from being forwarded outside a VPN, and they also prevent packets that are outsidea VPN from being forwarded to a device within the VPN.
How VPN Routing Information Is Distributed in an MPLS Virtual Private NetworkThe distribution of virtual private network (VPN) routing information is controlled through the use of VPNroute target communities, implemented by Border Gateway Protocol (BGP) extended communities. VPNrouting information is distributed as follows:
• When a VPN route that is learned from a customer edge (CE) device is injected into BGP, a list of VPNroute target extended community attributes is associated with it. Typically the list of route targetcommunity extended values is set from an export list of route targets associated with the virtual routingand forwarding (VRF) instance from which the route was learned.
• An import list of route target extended communities is associated with each VRF. The import list definesroute target extended community attributes that a route must have in order for the route to be importedinto the VRF. For example, if the import list for a particular VRF includes route target extendedcommunities A, B, and C, then any VPN route that carries any of those route target extendedcommunities—A, B, or C—is imported into the VRF.
BGP Distribution of VPN Routing InformationA provider edge (PE) device can learn an IP prefix from the following sources:
• A customer edge (CE) device by static configuration
• A Border Gateway Protocol (BGP) session with the CE device
• A Routing Information Protocol (RIP) exchange with the CE device
The IP prefix is a member of the IPv4 address family. After the PE device learns the IP prefix, the PE convertsit into a VPN-IPv4 prefix by combining it with an 8-byte route distinguisher (RD). The generated prefix is amember of the VPN-IPv4 address family. It uniquely identifies the customer address, even if the customersite is using globally nonunique (unregistered private) IP addresses. The route distinguisher used to generatethe VPN-IPv4 prefix is specified by a configuration command associatedwith the virtual routing and forwarding(VRF) instance on the PE device.
BGP distributes reachability information for VPN-IPv4 prefixes for each VPN. BGP communication occursat two levels:
• Within an IP domains, known as an autonomous system (interior BGP [IBGP])
• Between autonomous systems (external BGP [EBGP])
PE-PE or PE-RR (route reflector) sessions are IBGP sessions, and PE-CE sessions are EBGP sessions. In anEnhanced Interior Gateway Routing Protocol (EIGRP) PE-CE environment, when an EIGRP internal routeis redistributed into BGP by one PE, and then back into EIGRP by another PE, the originating router ID forthe route is set to the router ID of the second PE, replacing the original internal router ID.
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Multiprotocol BGP MPLS VPNHow an MPLS Virtual Private Network Works
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BGP propagates reachability information for VPN-IPv4 prefixes among PE devices by means of the BGPmultiprotocol extensions (refer to RFC 2283,Multiprotocol Extensions for BGP-4), which define support foraddress families other than IPv4. Using the extensions ensures that the routes for a given VPN are learnedonly by other members of that VPN, enabling members of the VPN to communicate with each other.
Major Components of an MPLS Virtual Private NetworkAnMultiprotocol Label Switching (MPLS)-based virtual private network (VPN) has three major components:
• VPN route target communities—A VPN route target community is a list of all members of a VPNcommunity. VPN route targets need to be configured for each VPN community member.
• Multiprotocol BGP (MP-BGP) peering of VPN community provider edge (PE) devices—MP-BGPpropagates virtual routing and forwarding (VRF) reachability information to all members of a VPNcommunity. MP-BGP peering must be configured on all PE devices within a VPN community.
• MPLS forwarding—MPLS transports all traffic between all VPN community members across a VPNservice-provider network.
A one-to-one relationship does not necessarily exist between customer sites and VPNs. A given site can be amember of multiple VPNs. However, a site can associate with only one VRF. A customer-site VRF containsall the routes available to the site from the VPNs of which it is a member.
How to Configure Multiprotocol BGP MPLS VPN
Configuring Multiprotocol BGP Connectivity on the PE Devices and RouteReflectors
SUMMARY STEPS
1. enable2. configure terminal3. router bgp as-number4. no bgp default ipv4-unicast5. neighbor {ip-address | peer-group-name} remote-as as-number6. neighbor {ip-address | peer-group-name} activate7. address-family vpnv4 [unicast]8. neighbor {ip-address | peer-group-name} send-community extended9. neighbor {ip-address | peer-group-name} activate10. end
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Multiprotocol BGP MPLS VPNMajor Components of an MPLS Virtual Private Network
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DETAILED STEPS
PurposeCommand or Action
Enables privileged EXEC mode.enableStep 1
Example:
Device> enable
• Enter your password if prompted.
Enters global configuration mode.configure terminal
Example:
Device# configure terminal
Step 2
Configures a Border Gateway Protocol (BGP) routing process and entersrouter configuration mode.
router bgp as-number
Example:
Device(config)# router bgp 100
Step 3
• The as-number argument indicates the number of an autonomoussystem that identifies the device to other BGP devices and tagsthe routing information passed along. The range is 0 to 65535.Private autonomous system numbers that can be used in internalnetworks are 64512 to 65535.
(Optional) Disables the IPv4 unicast address family on all neighbors.no bgp default ipv4-unicastStep 4
Example:
Device(config-router)# no bgp defaultipv4-unicast
• Use the no bgp default ipv4-unicast command if you are usingthis neighbor for Multiprotocol Label Switching (MPLS) routesonly.
Adds an entry to the BGP or multiprotocol BGP neighbor table.neighbor {ip-address | peer-group-name}remote-as as-number
Step 5
• The ip-address argument specifies the IP address of the neighbor.
Example:
Device(config-router)# neighbor 10.0.0.1remote-as 100
• The peer-group-name argument specifies the name of a BGP peergroup.
• The as-number argument specifies the autonomous system towhich the neighbor belongs.
Enables the exchange of information with a neighboring BGP device.neighbor {ip-address | peer-group-name}activate
Step 6
• The ip-address argument specifies the IP address of the neighbor.
Example:
Device