Table of Contents

‚	‚
‚ ‚	Table of Contents
‚ ‚	Index

Troubleshooting IP Routing Protocols (CCIE ‚ Professional Development)
By Faraz ‚  Shamim ‚  CCIE #4131, Zaheer ‚  Aziz ‚  CCIE #4127, Johnson ‚  Liu ‚  CCIE #2637, Abe ‚  Martey ‚  CCIE #2373
‚
Publisher	: Cisco Press
Pub Date	: May 07, 2002
ISBN	: 1-58705-019-6
Pages	: 912
Slots	: 2	‚   ‚

                   

‚   ‚   ‚		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