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EIGRP Network Design Solutions

Book Description

Ideal for professionals who are designing, implementing or troubleshooting enterprise, dial-up, or service provider networks with EIGRP.

  • Learn from troubleshooting and design scenarios based on real-world experience

  • Use all protocol families supported by EIGRP: IP, IPX, and AppleTalk

  • Explore EIGRP network operation issues and usage of scalability features

  • Deploy EIGRP over Frame Relay, ATM, and ISDN

  • Find coverage of all EIGRP technologies, including DUAL, transport protocol, and topology database

  • EIGRP Network Design Solutions uses case studies and real-world configuration examples to help you gain an in-depth understanding of the issues involved in designing, deploying, and managing EIGRP-based networks. It details proper designs that can be used to build large and scalable EIGRP-based networks, and documents possible ways each EIGRP feature can be used in network design, implementation, troubleshooting, and monitoring.

    With this comprehensive reference, you get detailed coverage of all EIGRP technologies, including DUAL, transport protocol, and topology database. In addition you get extensive coverage of EIGRP deployment over WAN and dial-up networks and information on such features as filter lists, route maps, summarization, EIGRP pacing, and MD5 authentication. EIGRP Network Design Solutions will help you build and maintain more scalable and reliable networks.

    Table of Contents

    1. Copyright
      1. Dedications
    2. About the Author
      1. About the Technical Reviewers
    3. Acknowledgments
    4. Introduction
      1. Objectives
      2. Intended Audience
      3. Organization
      4. Additional Background and Reference Information
      5. Applicability of EIGRP
    5. I. EIGRP Technology
      1. 1. EIGRP Concepts and Technology
        1. EIGRP Concepts—Metrics and Distances
        2. Initial IP EIGRP Configuration
        3. EIGRP Concepts—Metrics and Distances
          1. Computing a Composite Metric
          2. Computing Vector Metric
        4. DUAL—The Heart of EIGRP
          1. DUAL Terminology
            1. Upstream and Downstream Routers
            2. Reported Distance and Feasibility Distance
          2. Simple DUAL Operation—Adding New Routes
          3. DUAL Behavior on Route Loss
          4. Local Computation
          5. Diffusing Computation
            1. Starting a Diffusing Computation
            2. Receiving a Query Packet and Responding to It
            3. Finishing a Diffusing Computation
            4. A Diffused Computation Example
          6. Monitoring Diffusing Computation
          7. Stuck-in-Active Routes
        5. Summary
      2. 2. Advanced EIGRP Concepts, Data Structures, and Protocols
        1. EIGRP Transport Mechanisms and Protocols
          1. EIGRP Encapsulation Methods and Packet Format
          2. Hello Protocol
            1. Monitoring EIGRP Hello Protocol
          3. Reliable Transport Protocol
            1. Sequence Numbers and Acknowledgments
            2. Retransmissions and Retransmission Timers
            3. Mixed Multicast/Unicast Operation
        2. EIGRP Neighbors
        3. Discovering New Neighbors
          1. Initial Topology Table Exchange
          2. Adjacency Resets—Causes and Consequences
          3. Monitoring EIGRP Neighbors
        4. EIGRP Topology Table
          1. EIGRP Topology Table Contents
          2. Internal EIGRP Routes
          3. External Routes and Additional Route Attributes
          4. Monitoring Network Convergence through the EIGRP Topology Table
          5. Anomalies in EIGRP Topology Tables
        5. Building Routing Tables from EIGRP Topology Tables
          1. Administrative Distance of EIGRP Routes
          2. EIGRP Variance and Its Influence on Traffic Load Sharing
          3. Valid and Invalid Examples of Using Variance
        6. Summary
      3. 3. IPX EIGRP
        1. IPX EIGRP Configuration and Route Redistribution
        2. Integration of IPX RIP Metrics into IPX EIGRP and IPX Route Selection
          1. IPX RIP Refresher
          2. Redistribution between IPX RIP and IPX EIGRP
          3. Sample Redistribution Scenarios
        3. IPX SAP Integration
        4. Backward Compatibility of IPX EIGRP and IPX SAP
        5. Summary
      4. 4. AppleTalk EIGRP
        1. AppleTalk EIGRP Configuration and Route Redistribution
        2. Integration of RTMP and AppleTalk EIGRP and AppleTalk Route Selection
          1. RTMP Refresher
            1. Redistribution between RTMP and AppleTalk EIGRP
          2. Sample Redistribution Scenarios
            1. Scenario 1—Concurrent RTMP and AppleTalk Operation
            2. Scenario 2—RTMP Running on LAN Interfaces Only
            3. Scenario 3—Running RTMP on Some WAN Links
            4. Scenario 4—Discontinuous AppleTalk EIGRP Domain
        3. Summary
    6. II. Designing Enterprise EIGRP Networks
      1. 5. Scalability Issues in Large Enterprise Networks
        1. Case Study 1—Large Enterprise Network Experiencing Meltdown Situations
          1. Why Did DUAL-Mart Fail?
          2. Case Study Summary
        2. Query Boundaries—What They Are and Why They Are Useful
        3. Monitoring the Stability of Your EIGRP Network
        4. Case Study 2—Diffused Computation in Hierarchical Networks
          1. Remote Office PVC Failure
          2. Shadow PVC Failure
          3. Primary PVC Failure with Traffic Rerouting
        5. Summary
      2. 6. EIGRP Route Summarization
        1. Case Study—Connectivity Loss Following Private IP Address Deployment
          1. Autosummarization
          2. Query Boundaries with Autosummarization
          3. Conclusion
            1. Benefits and Drawbacks of Autosummarization
          4. Manual Per-Interface Summarization
            1. Why Do We Need a Summary Route to Null 0?
            2. EIGRP Query Boundary with Per-Interface Summarization
          5. Case Study—EIGRP Behavior in DUAL-Mart Network after Regional Summarization
            1. Remote Office PVC Failure
            2. Primary PVC Failure
            3. Case Study Analysis and Comparison with OSPF
          6. Case Study—EIGRP Behavior in DUAL-Mart Network after Two-Step Summarization
            1. Primary PVC Failure
        2. Summary
      3. 7. Route Filters
        1. Case Study—Partial Connectivity over ISDN Backup
        2. EIGRP Route Filters
        3. Query Boundaries Established by EIGRP Route Filters
        4. Case Study—DUAL-Mart ISDN Dial-Backup Network Redesign
        5. Prefix Lists—Improved Route Filters
        6. Case Study—Network Meltdown after Frame Relay Failure
        7. Summary
      4. 8. Default Routes
        1. IP Default Routing and IOS Specifics
          1. Classful and Truly Classless Routing in IOS
          2. Default Candidates and Gateways of Last Resort
          3. Monitoring Default Candidates
        2. Default Routes and Default Candidates in EIGRP
        3. EIGRP Default Routes—Design Examples
          1. Enterprise Network with a Single Connection to the Internet
          2. Enterprise Network with Multiple Connections to the Internet
        4. Case Study—GreatCoals Network
        5. Summary
      5. 9. Integrating EIGRP with Other Enterprise Routing Protocols
        1. Case Study 1—Large Network with No Addressing Structure
        2. Case Study 2—Large Network with No Layering
        3. Case Study 3—Network Migrating from Another Vendor to Cisco
        4. Case Study 4—Service Provider with a Large Number of Routes
        5. Redistribution between Routing Processes
        6. Various Redistribution Designs and Potential Caveats
          1. One-Point, One-Way Redistribution
          2. Multipoint One-Way Redistribution
          3. Multipoint Two-Way Redistribution
            1. Redistribute Only Internal Routes
            2. Redistribute Routes Using Route Tags
            3. Redistribution Control with Route Filters
        7. Case Study Solutions
          1. Case Study 1 Solution—Integrating RIP with EIGRP
          2. Case Study 2 Solution—Multiple EIGRP Processes
            1. Query Boundaries in Multiple EIGRP Processes
          3. Case Study 3 Solution—RIPv2 and EIGRP Integration with Filters
          4. Case Study 4 Solution—BGP and EIGRP Integration
        8. Summary
      6. 10. Designing Scalable IPX EIGRP Networks
        1. IPX Route Filters
        2. IPX Default Routes
        3. Controlling Route Redistribution between IPX Routing Protocols
        4. Case Study—GreatCoals
        5. Case Study—Reducing IPX EIGRP Diameter in GreatCoals Network
        6. Case Study—Combining IPX RIP and IPX EIGRP in an Access Network
        7. Summary
      7. 11. Designing Scalable AppleTalk EIGRP Networks
        1. AppleTalk EIGRP Route Filters
        2. Other AppleTalk EIGRP Scalability Options
        3. Case Study—Frisco Systems, Inc.
        4. Case Study Solution
        5. Summary
    7. III. Running EIGRP over Switched WAN and Dial-Up Networks
      1. 12. Switched WAN Networks and Their Impact on EIGRP
        1. Case Study 1—A Large Number of EIGRP Neighbors over a Frame Relay Link
        2. Broadcast Emulation on Switched WAN (Pseudobroadcasting)
        3. Layer 2 to Layer 3 Mapping in WAN Environment
        4. Troubleshooting Neighbor Map Problems
          1. Scenario 1—Missing Broadcast Keyword on a Neighbor Map
          2. Scenario 2—Wrong IP Address in the Neighbor Map
          3. Scenario 3—Wrong DLCI Number in the Neighbor Map
        5. Subinterfaces
          1. Point-to-Point and Multipoint Subinterfaces
          2. Creating, Configuring, and Removing Subinterfaces
          3. Using Subinterfaces to Reduce Interface Output Load Due to EIGRP Hello Packets
        6. Summary
      2. 13. Running EIGRP over WAN Networks
        1. Case Study—Improving Neighbor Loss Detection
          1. Overhead Placed on the WAN Links by the EIGRP Hello Packets
        2. Case Study—WAN Link Overload Due to EIGRP Traffic
          1. Load Control on WAN Links—EIGRP Pacing
          2. EIGRP Pacing Design
          3. EIGRP Pacing Design Examples
        3. Case Study—Partial Connectivity over Frame Relay
          1. EIGRP Split Horizon
        4. Running EIGRP over Various Switched WAN Technologies
          1. Running EIGRP over X.25
          2. Running EIGRP over Frame Relay
          3. Running EIGRP over ATM
        5. Summary
      3. 14. EIGRP and Dial-Up Networks
        1. Case Study—A Simple Dial-Up Network
          1. EIGRP Bandwidth Issues in Dial-Up Networks
          2. EIGRP Query Boundaries in a Dial-Up Environment
        2. Case Study—Route Flaps in a Dial-Up Environment
        3. Case Study—Dial-Out Requirements
          1. EIGRP Use in Dial-Out Requirements
        4. Case Study—EIGRP Use in a Dial-Backup Scenario
          1. EIGRP Neighbor Loss Detection Issues
        5. Summary
      4. 15. Secure EIGRP Operation
        1. Case Study—Collecting Usernames and Passwords through a Fake Server
        2. Case Study—Denial-of-Service Attack on a Core Network
        3. EIGRP MD5 Authentication
          1. Configuring EIGRP MD5 Authentication
          2. Shortcomings of EIGRP MD5 Authentication
          3. Design Issues and Guidelines
            1. Parameter 1—Scope of an Individual Key
            2. Parameter 2—Key Changes
            3. Parameter 3—Key Distribution
          4. Key Rollover Design and Integration with NTP
          5. Troubleshooting EIGRP MD5 Authentication
        4. Summary