‚ ‚ ‚ | | Copyright |
‚ ‚ ‚ | | About the Authors |
‚ ‚ ‚ | ‚ | | About the Technical Reviewers |
‚ ‚ ‚ | | Acknowledgments |
‚ ‚ ‚ | | Preface |
‚ ‚ ‚ | | Introduction |
‚ ‚ ‚ | ‚ | | Who Should Read This Book? |
‚ ‚ ‚ | ‚ | | How This Book Is Organized |
‚ ‚ ‚ | | Icons Used in This Book |
‚ ‚ ‚ | ‚ | | Command Syntax Conventions |
‚ ‚ ‚ | | Chapter ‚ 1. ‚ Understanding IP Routing |
‚ ‚ ‚ | ‚ | | IP Addressing Concepts |
‚ ‚ ‚ | ‚ | | Static and Dynamic Routes |
‚ ‚ ‚ | ‚ | | Dynamic Routing |
‚ ‚ ‚ | ‚ | | Routing Protocol Administrative Distance |
‚ ‚ ‚ | ‚ | | Fast Forwarding in Routers |
‚ ‚ ‚ | ‚ | | Summary |
‚ ‚ ‚ | ‚ | | Review Questions |
‚ ‚ ‚ | ‚ | | References |
‚ ‚ ‚ | | Chapter ‚ 2. ‚ Understanding Routing Information Protocol (RIP) |
‚ ‚ ‚ | ‚ | | Metric |
‚ ‚ ‚ | ‚ | | Timers |
‚ ‚ ‚ | ‚ | | Split Horizon |
‚ ‚ ‚ | ‚ | | Split Horizon with Poison Reverse |
‚ ‚ ‚ | ‚ | | RIP-1 Packet Format |
‚ ‚ ‚ | ‚ | | RIP Behavior |
‚ ‚ ‚ | ‚ | | Why RIP Doesn't Support Discontiguous Networks |
‚ ‚ ‚ | ‚ | | Why RIP Doesn't Support Variable-Length Subnet Masking |
‚ ‚ ‚ | ‚ | | Default Routes and RIP |
‚ ‚ ‚ | ‚ | | Protocol Extension to RIP |
‚ ‚ ‚ | ‚ | | Compatibility Issues |
‚ ‚ ‚ | ‚ | | Summary |
‚ ‚ ‚ | ‚ | | Review Questions |
‚ ‚ ‚ | ‚ | | Further Reading |
‚ ‚ ‚ | | Chapter ‚ 3. ‚ Troubleshooting RIP |
‚ ‚ ‚ | ‚ | | Flowcharts to Solve Common RIP Problems |
‚ ‚ ‚ | ‚ | | Troubleshooting RIP Routes Installation |
‚ ‚ ‚ | ‚ | | Problem: RIP Routes Not in the Routing Table |
‚ ‚ ‚ | ‚ | | Problem: RIP Is Not Installing All Possible Equal-Cost Paths ‚ Cause: maximum- path Command Restricts RIP from Installing More Than One Path |
‚ ‚ ‚ | ‚ | | Troubleshooting RIP Routes Advertisement |
‚ ‚ ‚ | ‚ | | Problem: Sender Is Not Advertising RIP Routes |
‚ ‚ ‚ | ‚ | | Problem: Subnetted Routes Missing from the Routing Table of R2 ‚ Cause: Autosummarization Feature Is Enabled |
‚ ‚ ‚ | ‚ | | Troubleshooting Routes Summarization in RIP |
‚ ‚ ‚ | ‚ | | Problem: RIP-2 Routing Table Is Huge ‚ Cause: Autosummarization Is Off |
‚ ‚ ‚ | ‚ | | Problem: RIP-2 Routing Table Is Huge ‚ Cause: ip summary-address Is Not Used |
‚ ‚ ‚ | ‚ | | Troubleshooting RIP Redistribution Problems |
‚ ‚ ‚ | ‚ | | Troubleshooting Dial-on-Demand Routing Issues in RIP |
‚ ‚ ‚ | ‚ | | Problem: RIP Broadcast Is Keeping the ISDN Link Up ‚ Cause: RIP Broadcasts Have Not Been Denied in the Interesting Traffic Definition |
‚ ‚ ‚ | ‚ | | Problem: RIP Updates Are Not Going Across the Dialer Interface ‚ Cause: Missing broadcast Keyword in a dialer map Statement |
‚ ‚ ‚ | ‚ | | Troubleshooting Routes Flapping Problem in RIP |
‚ ‚ ‚ | | Chapter ‚ 4. ‚ Understanding Interior Gateway Routing Protocol (IGRP) |
‚ ‚ ‚ | ‚ | | Metrics |
‚ ‚ ‚ | ‚ | | Timers |
‚ ‚ ‚ | ‚ | | Split Horizon |
‚ ‚ ‚ | ‚ | | Split Horizon with Poison Reverse |
‚ ‚ ‚ | ‚ | | IGRP Packet Format |
‚ ‚ ‚ | ‚ | | IGRP Behavior |
‚ ‚ ‚ | ‚ | | Default Route and IGRP |
‚ ‚ ‚ | ‚ | | Unequal-Cost Load Balancing in IGRP |
‚ ‚ ‚ | ‚ | | Summary |
‚ ‚ ‚ | ‚ | | Review Questions |
‚ ‚ ‚ | | Chapter ‚ 5. ‚ Troubleshooting IGRP |
‚ ‚ ‚ | ‚ | | Flowcharts to Solve Common IGRP Problems |
‚ ‚ ‚ | ‚ | | Troubleshooting IGRP Route Installation |
‚ ‚ ‚ | ‚ | | Problem: IGRP Routes Not in the Routing Table |
‚ ‚ ‚ | ‚ | | Problem: IGRP Is Not Installing All Possible Equal-Cost Paths ‚ Cause: maximum-paths Restricts IGRP to a Maximum of Four Paths by Default |
‚ ‚ ‚ | ‚ | | Troubleshooting IGRP Routes Advertisement |
‚ ‚ ‚ | ‚ | | Problem: Sender Is Not Advertising IGRP Routes |
‚ ‚ ‚ | ‚ | | Problem: Candidate Default Is Not Being Advertised ‚ Cause: ip default-network Command Is Missing |
‚ ‚ ‚ | ‚ | | Troubleshooting IGRP Redistribution Problems |
‚ ‚ ‚ | ‚ | | Problem: Redistributed Routes Are Not Getting Installed in the Routing Table ‚ Cause: Metric Is Not Defined During Redistribution into IGRP |
‚ ‚ ‚ | ‚ | | Troubleshooting Dial-on-Demand Routing (DDR) Issues in IGRP |
‚ ‚ ‚ | ‚ | | Problem: IGRP Broadcast Is Keeping the ISDN Link Up ‚ Cause: IGRP Broadcasts Have Not Been Denied in the Interesting Traffic Definition |
‚ ‚ ‚ | ‚ | | Problem: IGRP Updates Are Not Going Across the Dialer Interface ‚ Cause: Missing Broadcast Keyword in a dialer map Statement |
‚ ‚ ‚ | ‚ | | Troubleshooting Route Flapping Problem in IGRP |
‚ ‚ ‚ | ‚ | | Problem: IGRP Routes Are Flapping ‚ Cause: Packet Drops on Sender's or Receiver's Interface |
‚ ‚ ‚ | ‚ | | Troubleshooting Variance Problem |
‚ ‚ ‚ | ‚ | | Problem: IGRP Not Using Unequal-Cost Path for Load Balancing ‚ Cause: variance Command Is Missing or Misconfigured |
‚ ‚ ‚ | | Chapter ‚ 6. ‚ Understanding Enhanced Interior Gateway Routing Protocol (EIGRP) |
‚ ‚ ‚ | ‚ | | Metrics |
‚ ‚ ‚ | ‚ | | EIGRP Neighbor Relationships |
‚ ‚ ‚ | ‚ | | The Diffusing Update Algorithm |
‚ ‚ ‚ | ‚ | | DUAL Finite-State Machine |
‚ ‚ ‚ | ‚ | | EIGRP Reliable Transport Protocol |
‚ ‚ ‚ | ‚ | | EIGRP Packet Format |
‚ ‚ ‚ | ‚ | | EIGRP Behavior |
‚ ‚ ‚ | ‚ | | EIGRP Summarization |
‚ ‚ ‚ | ‚ | | EIGRP Query Process |
‚ ‚ ‚ | ‚ | | Default Routes and EIGRP |
‚ ‚ ‚ | ‚ | | Unequal-Cost Load Balancing in EIGRP |
‚ ‚ ‚ | ‚ | | Summary |
‚ ‚ ‚ | ‚ | | Review Questions |
‚ ‚ ‚ | | Chapter ‚ 7. ‚ Troubleshooting EIGRP |
‚ ‚ ‚ | ‚ | | Troubleshooting EIGRP Neighbor Relationships |
‚ ‚ ‚ | ‚ | | Troubleshooting EIGRP Route Advertisement |
‚ ‚ ‚ | ‚ | | Troubleshooting EIGRP Route Installation |
‚ ‚ ‚ | ‚ | | Troubleshooting EIGRP Route Flapping |
‚ ‚ ‚ | ‚ | | Troubleshooting EIGRP Route Summarization |
‚ ‚ ‚ | ‚ | | Troubleshooting EIGRP Redistribution Problems |
‚ ‚ ‚ | ‚ | | Troubleshooting EIGRP Dial Backup Problem |
‚ ‚ ‚ | ‚ | | EIGRP Error Messages |
‚ ‚ ‚ | ‚ | | Summary |
‚ ‚ ‚ | | Chapter ‚ 8. ‚ Understanding Open Shortest Path First (OSPF) |
‚ ‚ ‚ | ‚ | | OSPF Packet Details |
‚ ‚ ‚ | ‚ | | OSPF LSA Details |
‚ ‚ ‚ | ‚ | | OSPF Areas |
‚ ‚ ‚ | ‚ | | OSPF Media Types |
‚ ‚ ‚ | ‚ | | OSPF Adjacencies |
‚ ‚ ‚ | ‚ | | Summary |
‚ ‚ ‚ | ‚ | | Review Questions |
‚ ‚ ‚ | | Chapter ‚ 9. ‚ Troubleshooting OSPF |
‚ ‚ ‚ | ‚ | | Flowcharts to Solve Common OSPF Problems |
‚ ‚ ‚ | ‚ | | Troubleshooting OSPF Neighbor Relationships |
‚ ‚ ‚ | ‚ | | Problem: OSPF Neighbor List Is Empty |
‚ ‚ ‚ | ‚ | | Problem: OSPF Neighbor Stuck in INIT |
‚ ‚ ‚ | ‚ | | Problem: OSPF Neighbor Stuck in 2-WAY ‚ Cause: Priority 0 Is Configured on All Routers |
‚ ‚ ‚ | ‚ | | Problem: OSPF Neighbor Stuck in EXSTART/EXCHANGE |
‚ ‚ ‚ | ‚ | | Problem: OSPF Neighbor Stuck in LOADING |
‚ ‚ ‚ | ‚ | | Troubleshooting OSPF Route Advertisement |
‚ ‚ ‚ | ‚ | | Problem: OSPF Neighbor Is Not Advertising Routes |
‚ ‚ ‚ | ‚ | | Problem: OSPF Neighbor (ABR) Not Advertising the Summary Route |
‚ ‚ ‚ | ‚ | | Problem: OSPF Neighbor Is Not Advertising External Routes |
‚ ‚ ‚ | ‚ | | Problem: OSPF Neighbor Not Advertising Default Routes |
‚ ‚ ‚ | ‚ | | Troubleshooting OSPF Route Installation |
‚ ‚ ‚ | ‚ | | Problem: OSPF Not Installing Any Routes in the Routing Table |
‚ ‚ ‚ | ‚ | | Problem: OSPF Not Installing External Routes in the Routing Table |
‚ ‚ ‚ | ‚ | | Troubleshooting Redistribution Problems in OSPF |
‚ ‚ ‚ | ‚ | | Problem: OSPF Neighbor Is Not Advertising External Routes |
‚ ‚ ‚ | ‚ | | Troubleshooting Route Summarization in OSPF |
‚ ‚ ‚ | ‚ | | Problem: Router Is Not Summarizing Interarea Routes ‚ Cause: area range Command Is Not Configured on ABR |
‚ ‚ ‚ | ‚ | | Problem: Router Is Not Summarizing External Routes ‚ Cause: summary-address Command Is Not Configured on ASBR |
‚ ‚ ‚ | ‚ | | Troubleshooting CPUHOG Problems |
‚ ‚ ‚ | ‚ | | Problem: CPUHOG Messages During Adjacency Formation ‚ Cause: Router Is Not Running Packet-Pacing Code |
‚ ‚ ‚ | ‚ | | Problem: CPUHOG Messages During LSA Refresh Period ‚ Cause: Router Is Not Running LSA Group-Pacing Code |
‚ ‚ ‚ | ‚ | | Troubleshooting Dial-on-Demand Routing Issues in OSPF |
‚ ‚ ‚ | ‚ | | Problem: OSPF Hellos Are Bringing Up the Link ‚ Cause: OSPF Hellos Are Permitted as Interesting Traffic |
‚ ‚ ‚ | ‚ | | Problem: Demand Circuit Keeps Bringing Up the Link |
‚ ‚ ‚ | ‚ | | Troubleshooting SPF Calculation and Route Flapping |
‚ ‚ ‚ | ‚ | | SPF Running Constantly ‚ Cause: Interface Flap Within the Network |
‚ ‚ ‚ | ‚ | | SPF Running Constantly ‚ Cause: Neighbor Flap Within the Network |
‚ ‚ ‚ | ‚ | | SPF Running Constantly ‚ Cause: Duplicate Router ID |
‚ ‚ ‚ | ‚ | | Common OSPF Error Messages |
‚ ‚ ‚ | ‚ | | "Unknown routing protocol" Error Message |
‚ ‚ ‚ | ‚ | | OSPF: "Could not allocate router id" Error Message |
‚ ‚ ‚ | ‚ | | "%OSPF-4-BADLSATYPE: Invalid lsa: Bad LSA type" Type 6 Error Message |
‚ ‚ ‚ | ‚ | | "OSPF-4-ERRRCV" Error Message |
‚ ‚ ‚ | | Chapter ‚ 10. ‚ Understanding Intermediate System-to-Intermediate System (IS-IS) |
‚ ‚ ‚ | ‚ | | IS-IS Protocol Overview |
‚ ‚ ‚ | ‚ | | IS-IS Protocol Concepts |
‚ ‚ ‚ | ‚ | | IS-IS Link-State Database |
‚ ‚ ‚ | ‚ | | Configuring IS-IS for IP Routing |
‚ ‚ ‚ | ‚ | | Summary |
‚ ‚ ‚ | ‚ | | Additional IS-IS Packet Information |
‚ ‚ ‚ | ‚ | | Review Questions |
‚ ‚ ‚ | ‚ | | Further Reading |
‚ ‚ ‚ | | Chapter ‚ 11. ‚ Troubleshooting IS-IS |
‚ ‚ ‚ | ‚ | | Troubleshooting IS-IS Adjacency Problems |
‚ ‚ ‚ | ‚ | | Troubleshooting IS-IS Routing Update Problems |
‚ ‚ ‚ | ‚ | | IS-IS Errors |
‚ ‚ ‚ | ‚ | | CLNS ping and traceroute |
‚ ‚ ‚ | ‚ | | Case Study: ISDN Configuration Problem |
‚ ‚ ‚ | ‚ | | IS-IS Troubleshooting Command Summary |
‚ ‚ ‚ | ‚ | | Summary |
‚ ‚ ‚ | | Chapter 12. ‚ Understanding Protocol Independent Multicast (PIM) |
‚ ‚ ‚ | ‚ | | Fundamentals of IGMP Version 1, IGMP Version 2, and Reverse Path Forwarding |
‚ ‚ ‚ | ‚ | | PIM Dense Mode |
‚ ‚ ‚ | ‚ | | PIM Sparse Mode |
‚ ‚ ‚ | ‚ | | IGMP and PIM Packet Format |
‚ ‚ ‚ | ‚ | | Summary |
‚ ‚ ‚ | ‚ | | Review Questions |
‚ ‚ ‚ | | Chapter ‚ 13. ‚ Troubleshooting PIM |
‚ ‚ ‚ | ‚ | | Troubleshooting IGMP Joins |
‚ ‚ ‚ | ‚ | | Troubleshooting PIM Dense Mode |
‚ ‚ ‚ | ‚ | | Troubleshooting PIM Sparse Mode |
‚ ‚ ‚ | ‚ | | Summary |
‚ ‚ ‚ | | Chapter ‚ 14. ‚ Understanding Border Gateway Protocol Version 4 (BGP-4) |
‚ ‚ ‚ | ‚ | | BGP-4 Protocol Specification and Functionality |
‚ ‚ ‚ | ‚ | | Neighbor Relationships |
‚ ‚ ‚ | ‚ | | Advertising Routes |
‚ ‚ ‚ | ‚ | | Receiving Routes |
‚ ‚ ‚ | ‚ | | Policy Control |
‚ ‚ ‚ | ‚ | | Scaling IBGP in Large Networks ‚ Route Reflectors and Confederations |
‚ ‚ ‚ | ‚ | | Best-Path Calculation |
‚ ‚ ‚ | ‚ | | Summary |
‚ ‚ ‚ | ‚ | | Review Questions |
‚ ‚ ‚ | | Chapter ‚ 15. ‚ Troubleshooting BGP |
‚ ‚ ‚ | ‚ | | Flowcharts to Solve Common BGP Problems |
‚ ‚ ‚ | ‚ | | show and debug Commands for BGP-Related Troubleshooting |
‚ ‚ ‚ | ‚ | | Troubleshooting BGP Neighbor Relationships |
‚ ‚ ‚ | ‚ | | Problem: Directly Connected External BGP Neighbors Not Initializing |
‚ ‚ ‚ | ‚ | | Problem: Nondirectly Connected External BGP Neighbors Not Coming Up |
‚ ‚ ‚ | ‚ | | Problem: Internal BGP Neighbors Not Coming Up |
‚ ‚ ‚ | ‚ | | Problem: BGP Neighbors (External and Internal) Not Coming Up ‚ Cause: Interface Access List Blocking BGP Packets |
‚ ‚ ‚ | ‚ | | Troubleshooting BGP Route Advertisement /Origination and Receiving |
‚ ‚ ‚ | ‚ | | Problem: BGP Route Not Getting Originated |
‚ ‚ ‚ | ‚ | | BGP Route Not Getting Originated ‚ Cause: BGP Is Autosummarizing to Classful/Network Boundary |
‚ ‚ ‚ | ‚ | | Problem in Propagating/Originating BGP Route to IBGP/EBGP Neighbors ‚ Cause: Misconfigured Filters |
‚ ‚ ‚ | ‚ | | Problem in Propagating BGP Route to IBGP Neighbor but Not to EBGP Neighbor ‚ Cause: BGP Route Was from Another IBGP Speaker |
‚ ‚ ‚ | ‚ | | Problem in Propagating IBGP Route to IBGP/EBGP Neighbor ‚ Cause: IBGP Route Was Not Synchronized |
‚ ‚ ‚ | ‚ | | Troubleshooting BGP Route Not Installing in Routing Table |
‚ ‚ ‚ | ‚ | | Problem: IBGP-Learned Route Not Getting Installed in IP Routing Table |
‚ ‚ ‚ | ‚ | | IBGP-Learned Route Not Getting Installed in IP Routing Table ‚ Cause: IBGP Next Hop Not Reachable |
‚ ‚ ‚ | ‚ | | Problem: EBGP-Learned Route Not Getting Installed in IP Routing Table |
‚ ‚ ‚ | ‚ | | Troubleshooting BGP Route-Reflection Issues |
‚ ‚ ‚ | ‚ | | Problem: Configuration Mistakes ‚ Cause: Failed to Configure IBGP Neighbor as a Route-Reflector Client |
‚ ‚ ‚ | ‚ | | Problem: Route-Reflector Client Stores an Extra BGP Update ‚ Cause: Client-to-Client Reflection |
‚ ‚ ‚ | ‚ | | Problem: Convergence Time Improvement for RR and Clients ‚ Cause: Use of Peer Groups |
‚ ‚ ‚ | ‚ | | Problem: Loss of Redundancy Between Route Reflectors and Route-Reflector Client ‚ Cause: Cluster List Check in RR Drops Redundant Route from Other RR |
‚ ‚ ‚ | ‚ | | Troubleshooting Outbound IP Traffic Flow Issues Because of BGP Policies |
‚ ‚ ‚ | ‚ | | Problem: Multiple Exit Points Exist but Traffic Goes Out Through One or Few Exit Routers ‚ Cause: BGP Policy Definition Causes Traffic to Exit from One Place |
‚ ‚ ‚ | ‚ | | Problem: Traffic Takes a Different Interface from What Shows in Routing Table ‚ Cause: Next Hop of the Route Is Reachable Through Another Path |
‚ ‚ ‚ | ‚ | | Problem: Multiple BGP Connections to the Same BGP Neighbor AS, but Traffic Goes Out Through Only One Connection ‚ Cause: BGP Neighbor Is Influencing Outbound Traffic by Sending MED or Prepended AS_PATH |
‚ ‚ ‚ | ‚ | | Problem: Asymmetrical Routing Occurs and Causes a Problem Especially When NAT and Time-Sensitive Applications Are Used ‚ Cause: Outbound and Inbound Advertisement |
‚ ‚ ‚ | ‚ | | Troubleshooting Load-Balancing Scenarios in Small BGP Networks |
‚ ‚ ‚ | ‚ | | Problem: Load Balancing and Managing Outbound Traffic from a Single Router When Dual Homed to Same ISP ‚ Cause: BGP Installs Only One Best Path in the Routing Table |
‚ ‚ ‚ | ‚ | | Problem: Load Balancing and Managing Outbound Traffic in an IBGP Network ‚ Cause: By Default, IBGP in Cisco IOS Software Allows Only a Single Path to Get Installed in the Routing Table Even Though Multiple Equal BGP Paths Exist |
‚ ‚ ‚ | ‚ | | Troubleshooting Inbound IP Traffic Flow Issues Because of BGP Policies |
‚ ‚ ‚ | ‚ | | Troubleshooting BGP Best-Path Calculation Issues |
‚ ‚ ‚ | ‚ | | Problem: Path with Lowest RID Is Not Chosen as Best |
‚ ‚ ‚ | ‚ | | Problem: Lowest MED Not Selected as Best Path |
‚ ‚ ‚ | ‚ | | Troubleshooting BGP Filtering |
‚ ‚ ‚ | ‚ | | Problem: Standard Access List Fails to Capture Subnets |
‚ ‚ ‚ | ‚ | | Problem: Extended Access Lists Fails to Capture the Correct Masked Route |
‚ ‚ ‚ | ‚ | | Problem: AS_PATH Filtering Using Regular Expressions |
‚ ‚ ‚ | ‚ | | Summary |
‚ ‚ ‚ | | Appendix ‚ Answers to Review Questions |
‚ ‚ ‚ | ‚ | | Chapter 1 |
‚ ‚ ‚ | ‚ | | Chapter 2 |
‚ ‚ ‚ | ‚ | | Chapter 4 |
‚ ‚ ‚ | ‚ | | Chapter 6 |
‚ ‚ ‚ | ‚ | | Chapter 8 |
‚ ‚ ‚ | ‚ | | Chapter 10 |
‚ ‚ ‚ | ‚ | | Chapter 12 |
‚ ‚ ‚ | ‚ | | Chapter 14 |
‚ ‚ ‚ | | Index |