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MPLS and VPN Architectures, CCIP™ Edition

Book Description

Prepare for CCIP certification as you learn to design and deploy MPLS-based VPNs

  • Assists in preparation for the CCIP MPLS elective exam with detailed technology coverage and review questions

  • Offers in-depth analysis of MPLS architecture

  • Helps you learn how MPLS scales to support tens of thousands of virtual private networks (VPNs)

  • Provides extensive case studies that guide you through the design and deployment of real-world MPLS/VPN networks

  • Presents configuration examples and guidelines that assist you in configuring MPLS on Cisco devices

  • Provides design and implementation options that help you build various VPN topologies

  • Multiprotocol Label Switching (MPLS) is an innovative technique for high-performance packet forwarding. The most widely deployed usage of MPLS today is the enabling of VPNs. With the introduction of MPLS-enabled VPNs, network designers can better scale their networks than ever before.

    MPLS and VPN Architectures, CCIP Edition, is a practical guide to understanding, designing, and deploying MPLS-based VPNs. This book covers MPLS theory and configuration, network design issues, and one major MPLS application: MPLS-based VPNs. The MPLS/VPN architecture and all its mechanisms are explained with configuration examples, suggested design and deployment guidelines, and extensive case studies.

    This book has been revised from the first edition to include coverage of the CCIP MPLS elective exam. New chapters cover MPLS troubleshooting and MPLS/VPN troubleshooting; self-assessment questions at the end of each chapter help you prepare for the CCIP MPLS elective exam. CCIP candidates choosing to follow the MPLS elective will find this book to be a valuable self-study component in their exam preparation.

    MPLS and VPN Architectures, CCIP Edition, is part of a recommended learning path from Cisco Systems that can include simulation and hands-on training from authorized Cisco Learning Partners and self-study products from Cisco Press. To find out more about instructor-led training, e-learning, and hands-on instruction offered by authorized Cisco Learning Partners worldwide, please visit

    Table of Contents

    1. Copyright
      1. Dedications
    2. About the Authors
    3. About the Technical Reviewers
    4. Acknowledgments
    5. Introduction
      1. CCIP Certification Process
      2. Goals and Methods
      3. Who Should Read This Book?
      4. Strategies for Exam Preparation
      5. How This Book Is Organized
      6. Icons Used in This Book
      7. Command Syntax Conventions
    6. I. MPLS Technology and Configuration
      1. 1. Multiprotocol Label Switching (MPLS) Architecture Overview
        1. Scalability and Flexibility of IP-based Forwarding
          1. Network Layer Routing Paradigm
          2. Differentiated Packet Servicing
          3. Independent Forwarding and Control
          4. External Routing Information Propagation
        2. Multiprotocol Label Switching (MPLS) Introduction
          1. MPLS Architecture—The Building Blocks
          2. Label Imposition at the Network Edge
          3. MPLS Packet Forwarding and Label Switched Paths
        3. Other MPLS Applications
        4. Summary
        5. Review Questions
      2. 2. Frame-mode MPLS Operation
        1. Frame-mode MPLS Data Plane Operation
          1. MPLS Label Stack Header
          2. Label Switching in Frame-mode MPLS
            1. MPLS Label Switching with Label Stack
        2. Label Bindings and Propagation in Frame-mode MPLS
          1. LDP/TDP Session Establishment
          2. Label Binding and Distribution
          3. Convergence in a Frame-mode MPLS Network
        3. Penultimate Hop Popping
        4. MPLS Interaction with Border Gateway Protocol
        5. Summary
        6. Review Questions
      3. 3. Cell-mode MPLS Operation
        1. Control-plane Connectivity Across an LC-ATM Interface
          1. MPLS Control-plane Connectivity in Cisco IOS Software
          2. Control-plane Implementation in an ATM Switch
        2. Labeled Packet Forwarding Across an ATM-LSR Domain
        3. Label Allocation and Distribution Across an ATM-LSR Domain
          1. VC Merge
          2. Convergence Across an ATM-LSR Domain
        4. Summary
        5. Review Questions
      4. 4. Running Frame-mode MPLS Across Switched WAN Media
        1. Frame-mode MPLS Operation Across Frame Relay
        2. Frame-mode MPLS Operation Across ATM PVCs
          1. Frame-mode and Cell-mode MPLS Across the Same ATM Interface
        3. Summary
        4. Review Questions
      5. 5. Advanced MPLS Topics
        1. Controlling the Distribution of Label Mappings
        2. MPLS Encapsulation Across Ethernet Links
          1. IP MTU Path Discovery
          2. Ethernet Switches and MPLS MTU
        3. MPLS Loop Detection and Prevention
          1. Loop Detection and Prevention in Frame-mode MPLS
            1. Frame-mode: Data Plane Loop Detection
            2. Frame-mode: Control Plane Loop Prevention
          2. Loop Detection and Prevention in Cell-mode MPLS
            1. Cell-mode: Control Plane Loop Detection/Prevention
            2. Cell-mode–—Data Plane Loop Detection
        4. Traceroute Across an MPLS-enabled Network
        5. Route Summarization Within an MPLS-enabled Network
        6. Summary
        7. Review Questions
      6. 6. MPLS Migration and Configuration Case Study
        1. Migration of the Backbone to a Frame-mode MPLS Solution
        2. Pre-migration Infrastructure Checks
          1. Cisco Express Forwarding (CEF) Requirements
        3. Addressing the Internal BGP Structure
        4. Migration of Internal Links to MPLS
        5. Removal of Unnecessary BGP Peering Sessions
        6. Migration of an ATM-based Backbone to Frame-mode MPLS
          1. Cell-mode MPLS Migration
        7. Summary
        8. Review Questions
    7. II. MPLS-based Virtual Private Networks
      1. 7. MPLS Troubleshooting
        1. Quick MPLS-related Checks
          1. Is CEF Enabled Globally?
          2. Is MPLS Enabled?
          3. Is MPLS Enabled on All Interfaces?
        2. MPLS Control Plane Troubleshooting
          1. Verify Local TDP/LDP Parameters
          2. Verify Correct Operation of TDP/LDP Hello Protocol
          3. Check TDP/LDP Sessions
          4. Check the Label Exchange
        3. MPLS Data Plane Troubleshooting
          1. Monitoring Interface-level CEF
          2. Monitoring End-to-end MPLS Path
          3. Oversized Packet Issues
        4. Summary
        5. Review Questions
      2. 8. Virtual Private Network (VPN) Implementation Options
        1. Virtual Private Network Evolution
          1. Modern Virtual Private Networks
        2. Business Problem-based VPN Classification
        3. Overlay and Peer-to-peer VPN Model
          1. Overlay VPN Model
          2. Peer-to-peer VPN Model
            1. Shared-router Approach to Peer-to-peer VPN Model
            2. Dedicated-router Approach to Peer-to-peer Model
            3. Comparison of Peer-to-peer Models
        4. Typical VPN Network Topologies
          1. Hub-and-spoke Topology
          2. Partial- or Full-mesh Topology
          3. Hybrid Topology
          4. Simple Extranet Topology
          5. Central-services Extranet
          6. VPDN Topology
          7. Managed Network VPN Topology
        5. Summary
        6. Review Questions
      3. 9. MPLS/VPN Architecture Overview
        1. Case Study: Virtual Private Networks in SuperCom Service Provider Network
        2. VPN Routing and Forwarding Tables
        3. Overlapping Virtual Private Networks
        4. Route Targets
        5. Propagation of VPN Routing Information in the Provider Network
          1. Multiprotocol BGP in the SuperCom Network
        6. VPN Packet Forwarding
        7. Summary
        8. Review Questions
      4. 10. MPLS/VPN Architecture Operation
        1. Case Study: Basic MPLS/VPN Intranet Service
        2. Configuration of VRFs
        3. Route Distinguishers and VPN-IPv4 Address Prefixes
          1. Configuration of the Route Distinguisher
        4. BGP Extended Community Attribute
          1. Route Target BGP Extended Community
            1. Configuration of Import and Export Policies
          2. Site of Origin BGP Extended Community
            1. Configuration of the SOO
          3. BGP Extended Community Attribute Format
        5. Basic PE-to-CE Link Configuration
          1. PE-to-CE Link Configuration—Static Routing
          2. PE-to-CE Link Configuration—RIP Version 2
        6. Association of Interfaces to VRFs
        7. Multiprotocol BGP Usage and Deployment
          1. Configuration of Multiprotocol BGP
          2. Enhanced BGP Decision Process for VPN-IPv4 Prefixes
        8. Outbound Route Filtering (ORF) and Route Refresh Features
          1. Automatic Route Filtering on PE Routers
          2. Refreshing Routing Information Between PE Routers
          3. ORF for PE Routers
        9. MPLS/VPN Data Plane—Packet Forwarding
        10. Summary
        11. Review Questions
      5. 11. Provider Edge (PE) to Customer Edge (CE) Connectivity Options
        1. VPN Customer Access into the MPLS/VPN Backbone
        2. BGP-4 Between Service Provider and Customer Networks
        3. Open Shortest Path First (OSPF) Between PE and CE Routers
        4. Separation of VPN Customer Routing Information
        5. Propagation of OSPF Routes Across the MPLS/VPN Backbone
          1. BGP Extended Community Attribute for OSPF Routes
        6. PE-to-CE Connectivity—OSPF with Site Area 0 Support
        7. PE-to-CE Connectivity—OSPF Without Site Area 0 Support
        8. VPN Customer Connectivity—MPLS/VPN Design Choices
          1. Migrating Customers Using iBGP in Their Network to MPLS/VPN Service
          2. Autonomous System Number Override
        9. Summary
        10. Review Questions
      6. 12. Advanced MPLS/VPN Topologies
        1. Intranet and Extranet Integration
        2. Central Services Topology
        3. MPLS/VPN Hub-and-spoke Topology
          1. Deployment of the AllowAS-in Feature
        4. Summary
        5. Review Questions
      7. 13. Advanced MPLS/VPN Topics
        1. MPLS/VPN: Scaling the Solution
        2. Routing Convergence Within an MPLS-enabled VPN Network
          1. Convergence Within the Service Provider Backbone
            1. Service Provider Backbone Convergence—Router-based Topology
            2. Service Provider Backbone Convergence—ATM-based Topology
          2. Convergence Between VPN Sites
        3. Advertisement of Routes Across the Backbone
          1. BGP for VPN-IPv4 and IPv4 Routing Information
          2. Full Mesh of MP-iBGP Between PE Routers
          3. Separation of MP-iBGP Sessions Between PE Routers
        4. Introduction of Route Reflector Hierarchy
          1. Route Reflection of PE Routes to Aid Scaling
          2. Route Reflector Partitioning
          3. Standard Community Filtering on PE Routers
          4. Route Target Attribute-based Filtering on Route Reflectors
          5. Route Reflection and ORF Capability
        5. BGP Confederations Deployment
          1. BGP Confederations—Single IGP Environment
          2. BGP Confederations—Multiple IGP Environment
        6. PE Router Provisioning and Scaling
        7. Additional Connectivity Requirements—Internet Access
        8. Internet Connectivity Through Firewalls
        9. Internet Access—Static Default Routing
        10. Separate BGP Session Between PE and CE Routers
        11. Internet Connectivity Through Dynamic Default Routing
          1. Dynamic Default Routing—Route Target Assignment
          2. Association of the Global Routing Table with a VRF
        12. Additional Lookup in the Global Routing Table
        13. Internet Connectivity Through a Different Service Provider
        14. Summary
        15. Review Questions
      8. 14. Guidelines for the Deployment of MPLS/VPN
        1. Introduction to MPLS/VPN Deployment
        2. IGP to BGP Migration of Customer Routes
        3. Multiprotocol BGP Deployment in an MPLS/VPN Backbone
          1. VPN Routes and Next-hop Forwarding
          2. PE Router Loopback Address Configuration
            1. Summarization of PE Loopback Addresses
        4. MPLS/VPN Deployment on LAN Interfaces
        5. Network Management of Customer Links
          1. Advertisement of Routes with Different Extended Communities
          2. Use of Standard BGP Communities for Route Filtering
          3. Advertisement of Routes with Different Route Targets Using Export Maps
        6. Use of Traceroute Across an MPLS/VPN Backbone
        7. Summary
        8. Review Questions
      9. 15. Carrier's Carrier and Inter-provider VPN Solutions
        1. Carrier's Carrier Solution Overview
        2. Carrier's Carrier Architecture—Topologies
          1. ISP with No MPLS Deployment Within POP Sites
          2. ISP with MPLS Deployed Within POP Sites
        3. Hierarchical Virtual Private Networks
        4. Inter-provider VPN Solutions
          1. Inter-provider VPN—Exchange of VPN-IPv4 Across Boundaries
          2. Inter-provider VPN—Multi-hop eBGP Between Customer Sites
        5. Summary
        6. Review Questions
      10. 16. IP Tunneling to MPLS/VPN Migration Case Study
        1. Existing VPN Solution Deployment—IP Tunneling
        2. Definition of VPNs and Routing Policies for PE Routers
        3. Definition of VRFs Within the Backbone Network
        4. VRF and Routing Polices for SampleNet VPN Sites
        5. VRF and Routing Policies for SampleNet Internet Access
        6. VRF and Routing Policies for Internet Access Customers
        7. MPLS/VPN Migration—Staging and Execution
          1. Migration of the SampleNet Central Site
        8. Configuration of MP-iBGP on BGP Route Reflectors
        9. Configuration of MP-iBGP on TransitNet PE Routers
        10. Migration of VPN Sites onto the MPLS/VPN Solution
        11. Summary
        12. Review Questions
      11. 17. MPLS VPN Troubleshooting
        1. Quick MPLS-related Checks
          1. Pinging Between the CE Routers
          2. Checking for an End-to-end LSP Between PE Routers
          3. Checking for CEF Switching
        2. In-depth MPLS VPN Troubleshooting
          1. Checking the Egress CE-to-PE Routing Exchange
          2. Checking the Route Export Functionality
          3. Checking the Propagation of MPLS VPN Routes
          4. Checking the Route Import Functionality
          5. Checking the Ingress PE-to-CE Routing Exchange
        3. Summary
        4. Review Questions
      12. A. Answers to Review Questions
        1. Chapter 1
        2. Chapter 2
        3. Chapter 3
        4. Chapter 4
        5. Chapter 5
        6. Chapter 6
        7. Chapter 7
        8. Chapter 8
        9. Chapter 9
        10. Chapter 10
        11. Chapter 11
        12. Chapter 12
        13. Chapter 13
        14. Chapter 14
        15. Chapter 15
        16. Chapter 16
        17. Chapter 17
      13. B. Tag-switching and MPLS Command Reference