Optimal Routing Design

<p><strong>Contents</strong></p> <p>Foreword</p> <p>Introduction</p> <p>Part I <strong>Network Design Overview</strong></p> <p>Chapter 1 Network Design Goals and Techniques</p> <p>Goals for Network Design</p> <p>Reliability</p> <p>Packet Delivery Reliability</p> <p>Packet Delivery Times</p> <p>Delay and Jitter Budgets</p> <p>The Impact of Network Design on Delay and Jitter Budgets</p> <p>Reliability and Resiliency</p> <p>Defining Network Failure</p> <p>Network Recovery Time</p> <p>Manageability</p> <p>Day-to-Day Operational Maintenance</p> <p>Taking a Network Baseline</p> <p>Network Documentation</p> <p>Emergency Management</p> <p>Scalability</p> <p>Redundancy</p> <p>How Redundancy Increases Resiliency</p> <p>Statistical Analysis</p> <p>How Redundancy Can Increase Management Complexity</p> <p>How Redundancy Can Reduce Scalability</p> <p>Layering</p> <p>Hiding Information</p> <p>Hiding Topology Information</p> <p>Hiding Reachability Information</p> <p>Separate Functionality</p> <p>Summary</p> <p>Review Questions</p> <p>Chapter 2 Applying the Fundamentals</p> <p>Hierarchical Design</p> <p>Abstraction Through Layering</p> <p>Horizontal Layers in a Network</p> <p>Layer Functions</p> <p>Forwarding Traffic</p> <p>Aggregation of Routing Information</p> <p>Definition and Implementation of Routing Policies</p> <p>User Attachment</p> <p>Controlling Traffic Admittance into the Network</p> <p>Network Hierarchies</p> <p>Two-Layer Hierarchy</p> <p>Three-Layer Hierarchy</p> <p>Determining How Many Layers to Use in Network Design</p> <p>Hiding Layers Within Layers</p> <p>Creating Layers</p> <p>Creating Choke Points</p> <p>Separating Complexity from Complexity</p> <p>Addressing and Summarization</p> <p>Assigning Addresses in a Network</p> <p>Working Around Addressing</p> <p>Leaking More Specifics</p> <p>Smaller Summary Blocks</p> <p>Change the Logical Layout</p> <p>Summary Issues</p> <p>Summarization Black Holes</p> <p>Summary Suboptimal Routing</p> <p>Summary Metrics</p> <p>Redistribution</p> <p>Alternatives to IGP to IGP Redistribution</p> <p>Single Point of Redistribution</p> <p>Multiple Points of Redistribution</p> <p>Filters</p> <p>Tags</p> <p>Review Questions</p> <p><strong>Part II Interior Gateway Protocols</strong></p> <p>Chapter 3 EIGRP Network Design</p> <p>Deploying EIGRP on a Large-Scale Three-Layer Hierarchical Network</p> <p>Analyzing the Network Core for Summarization</p> <p>Summarizing from the Core to the Distribution Layer</p> <p>Summarizing into the Core at Its Edge</p> <p>Analyzing the Network Distribution Layer for Summarization</p> <p>Summarizing Toward the Network Core</p> <p>Summarizing Toward the Remote Sites</p> <p>Analyzing Routing in the Network Access Layer</p> <p>Single-Homed Sites</p> <p>Dual-Homed Remotes</p> <p>Analyzing Use of the Stub Feature in Access Routers</p> <p>Analyzing Routes to External Connections</p> <p>Analyzing Routes to the Common Services Area</p> <p>Analyzing Routes to Dial-In Clients</p> <p>Host Routes</p> <p>Bandwidth Issues</p> <p>Deploying EIGRP on a Two-Layer Hierarchical Network</p> <p>Summarization in the Core</p> <p>Summarization in the Aggregation Layer</p> <p>Summary of EIGRP Network Design</p> <p>New Features in EIGRP</p> <p>Third-Party Next Hop</p> <p>NBMA Hub-and-Spoke Network</p> <p>Redistributed Next Hop</p> <p>Enhanced Route Map Support</p> <p>Before Enhanced Route Map Support</p> <p>Route Map Enhancements</p> <p>Enhanced EIGRP Active Process</p> <p>Case Study: Summarization Methods</p> <p>IP Summary Addresses</p> <p>Distribute Lists</p> <p>Case Study: Controlling Query Propagation</p> <p>Case Study: A Plethora of Topology Table Entries</p> <p>Case Study: Troubleshooting EIGRP Neighbor Relationships</p> <p>EIGRP Neighbor Relationships: Common Problem 1</p> <p>EIGRP Neighbor Relationships: Common Problem 2</p> <p>Case Study: Troubleshooting SIA Routes</p> <p>Case Study: Redistribution</p> <p>Using Distribute Lists to Prevent Redistribution Routing Loops</p> <p>Using Route Maps to Prevent Redistribution Routing Loops</p> <p>Using Prefix Lists to Prevent Redistribution Routing Loops</p> <p>Setting the Administrative Distance to Troubleshoot Redistribution Routing Loops</p> <p>Using External Flags to Prevent Redistribution Routing Loops</p> <p>Case Study: Retransmissions and SIA</p> <p>The Hold Timer</p> <p>SIA Timer</p> <p>Interaction Between the Hold Timer and the SIA Timer</p> <p>Case Study: Multiple EIGRP Autonomous Systems</p> <p>Review Questions</p> <p>Chapter 4 OSPF Network Design</p> <p>Summarization and Aggregation</p> <p>Deploying OSPF on a Three-Layer Hierarchy</p> <p>The Core Routers as ABRs</p> <p>The Distribution Layer Routers as ABRs</p> <p>Mixing ABR Locations</p> <p>Deploying OSPF on a Two-Layer Hierarchy</p> <p>Reducing Flooding Through Stub Areas</p> <p>Stub Areas</p> <p>Totally Stubby Areas</p> <p>Not-So-Stubby Areas</p> <p>Totally NSSA</p> <p>Totally Stubby Not Really Full Areas</p> <p>When to Use Stub Areas</p> <p>Aggregating Routes in OSPF</p> <p>Filtering Routes in OSPF</p> <p>Deploying OSPF on Specific Topologies</p> <p>Redistribution into OSPF</p> <p>External Route Metrics</p> <p>External Route Selection at ABRs</p> <p>Route Selection Between Processes</p> <p>Full Mesh Topologies</p> <p>Hub-and-Spoke Topologies</p> <p>Treating the NBMA Interface as a Broadcast Interface</p> <p>Treating the NBMA Interface as a Set of Point-to-Point Interfaces</p> <p>Treating an NBMA Interface as a Broadcast Point-to-Multipoint Interface</p> <p>Treating an NBMA Interface as a Nonbroadcast Point-to-Multipoint Interface</p> <p>Summary of Interface and OSPF Link-Type Options</p> <p>Reducing Flooding to the Spokes</p> <p>Links Parallel to Area Boundaries</p> <p>Dial Links</p> <p>Point-to-point Broadcast Links</p> <p>Case Study: OSPF Externals and the Next Hop</p> <p>Case Study: Troubleshooting OSPF Neighbor Adjacencies</p> <p>Review Questions</p> <p>Chapter 5 IS-IS Network Design</p> <p>Deploying IS-IS on a Three-Layer Hierarchy</p> <p>The Entire Network as a Single Routing Domain</p> <p>The Core as the L2 Domain</p> <p>Merging the Core and Distribution Layers into Level 2</p> <p>Mixing and Overlapping the Level 1/Level 2 Border</p> <p>Deploying IS-IS on a Two-Layer Hierarchy</p> <p>Working with IS-IS Routing Areas</p> <p>Leaking Routes into an L1 Routing Domain</p> <p>Aggregating Routes in IS-IS</p> <p>Deploying IS-IS on Specific Topologies</p> <p>Redistribution</p> <p>Full Mesh Topologies</p> <p>Hub-and-Spoke Topologies</p> <p>Point-to-Point Links</p> <p>Broadcast Interfaces</p> <p>Point-to-Point Broadcast Links</p> <p>Links Parallel to Area Boundaries</p> <p>Other Considerations in IS-IS Scaling</p> <p>Metrics</p> <p>Excessive Link-State Flooding</p> <p>LSP Corruption</p> <p>Maximum Number of Pseudonodes</p> <p>Prefix-Driven Routing Table Installation</p> <p>Hello Padding Suppression</p> <p>Case Study: Troubleshooting IS-IS Neighbor Relationships</p> <p>Review Questions</p> <p><strong>Part II Advanced Network Design</strong></p> <p>Chapter 6 BGP Cores and Network Scalability</p> <p>Case Study: Troubleshooting BGP Neighbor Relationships</p> <p>No IP Connectivity</p> <p>eBGP Multihop</p> <p>Other BGP Neighbor Problems</p> <p>Logging Neighbor Changes</p> <p>BGP in the Core</p> <p>Case Study: Sample Migration</p> <p>Scaling Beyond the Core</p> <p>Dividing the Network into Pieces</p> <p>Regional IGPs</p> <p>BGP Network Growing Pains</p> <p>BGP Update Generation Issues</p> <p>Reducing the Number of Updates Generated</p> <p>Case Study: Route Reflectors as Route Servers</p> <p>External Connections</p> <p>Case Study: Dual-Homed Connections to the Internet</p> <p>Load Sharing on the Outbound Side</p> <p>Load Sharing on the Inbound Side</p> <p>Being a Transit AS</p> <p>Case Study: Conditional Advertisement</p> <p>Case Study: Route Dampening</p> <p>Review Questions</p> <p>Chapter 7 High Availability and Fast Convergence</p> <p>Considerations in Fast Convergence</p> <p>Network Meltdowns</p> <p>Solving the Meltdown</p> <p>Designing Routing Protocols Not to Melt</p> <p>Do Not Report Everything You See</p> <p>Non-Stop Forwarding</p> <p>Graceful Restart</p> <p>EIGRP Graceful Restart</p> <p>OSPF Graceful Restart</p> <p>IS-IS Graceful Restart</p> <p>BGP Graceful Restart</p> <p>Fast Down Detection</p> <p>Detecting a Link or Adjacency Failure Using Polling</p> <p>Bidirectional Forwarding Detection</p> <p>Detecting a Link or Adjacency Failure Using Event-Driven Link Failure Notification</p> <p>SONET</p> <p>Frame Relay</p> <p>Ethernet</p> <p>Slowing Down When the Network Speeds Up</p> <p>Link-State Exponential Backoff</p> <p>Configuring OSPF Exponential Backoff for LSA Generation</p> <p>Configuring OSPF Exponential Backoff for Running SPF</p> <p>Configuring IS-IS Exponential Backoff</p> <p>IP Event Dampening</p> <p>Configuring IP Event Dampening</p> <p>Calculating the Route Faster</p> <p>EIGRP Feasible Successors</p> <p>Link-State Partial SPF</p> <p>Link-State Incremental SPF</p> <p>Deploying GR and Fast Convergence Technologies</p> <p>Graceful Restart Versus Fast Down Detection</p> <p>How Fast Can GR Work?</p> <p>Balancing Between GR and Fast Down Detection</p> <p>Deploying Graceful Restart with BGP and an Interior Gateway <br>Protocol (IGP)</p> <p>Deploying Exponential Backoff for Fast Convergence</p> <p>Setting SPF Exponential Backoff Timers</p> <p>Review Questions</p> <p>Chapter 8 Routing Protocol Security</p> <p>Fundamentals of Routing and Security</p> <p>Understanding What a Routing System Is</p> <p>Thoughts on Authorization and Authentication</p> <p>Defining Authentication and Authorization</p> <p>Transiting Authentication and Authorization</p> <p>Transiting Authorization in a Routing System</p> <p>Trust and Security</p> <p>Determining the Reasons for an Attack on the Routing System</p> <p>Types of Attacks Against Routing Systems</p> <p>Disrupting Peering</p> <p>Transport-Level Attacks Against OSPF and IS-IS</p> <p>Transport-Level Attacks Against EIGRP</p> <p>Transport-Level Attacks Against Border Gateway Protocol (BGP)</p> <p>Protocol-Layer Attacks</p> <p>Falsifying Routing Information</p> <p>Disrupting Routing Domain Stability</p> <p>Protecting Routing Domain Legitimacy</p> <p>Protecting Routers from Being Compromised</p> <p>Use Passwords</p> <p>Filter Access to Routers</p> <p>Protecting Against Illegitimate Devices Joining the Routing Domain</p> <p>MD5 Authentication</p> <p>Issues with MD5 Peer Authentication</p> <p>IPSec</p> <p>Protecting Routers from Denial-of-Service Attacks</p> <p>Edge Filters</p> <p>The Generalized TTL Security Mechanism</p> <p>Protecting Routing Information</p> <p>Extranet Connections</p> <p>Use an Exterior Gateway Protocol for All Extranet Connections</p> <p>Filter Routes Aggressively at the Extranet Edge</p> <p>Dampen Prefixes Aggressively at the Extranet Edge</p> <p>Limiting Route Count at the Extranet Edge</p> <p>Connections to the Internet</p> <p>Route Filtering</p> <p>Protecting Against Transit</p> <p>Route Dampening</p> <p>Future Directions in Routing Protocol Security</p> <p>Protecting Against Illegitimate Devices Joining the Routing Domain</p> <p>Secure Origin BGP (soBGP)</p> <p>Begin at the Beginning: Who Are You?</p> <p>The First Goal: Are You Authorized?</p> <p>The Second Goal: Do You Really Have a Path?</p> <p>Review Questions</p> <p>References</p> <p>Chapter 9 Virtual Private Networks</p> <p>MPLS</p> <p>MPLS Basics</p> <p>Overlay Routing over MPLS VPNs</p> <p>Peer-to-Peer (Redistributed) Routing over MPLS VPNs</p> <p>BGP/MPLS VPNs</p> <p>EIGRP</p> <p>OSPF</p> <p>IPSec</p> <p>GRE</p> <p>NHRP</p> <p>Case Study: NHRP in an ATM Network</p> <p>Dynamic Multipoint IPSec VPNs</p> <p>Review Questions</p> <p>References</p> <p><strong>Part II Appendixes</strong></p> <p>Appendix A EIGRP for IP Basics of Operation</p> <p>Appendix B OSPF Basics of Operation</p> <p>Appendix C Integrated IS-IS Basics of Operation</p> <p>Appendix D Border Gateway Protocol 4 Basics of Operation</p> <p>Appendix E IP Network Design Checklist</p> <p>Appendix F Answers to Review Questions</p> <p>Appendix G Which Routing Protocol?</p> <p>Index</p>