Home > Store

Troubleshooting IP Routing Protocols (CCIE Professional Development Series)

Register your product to gain access to bonus material or receive a coupon.

Troubleshooting IP Routing Protocols (CCIE Professional Development Series)

eBook (Watermarked)

  • Your Price: $51.19
  • List Price: $63.99
  • Includes EPUB and PDF
  • About eBook Formats
  • This eBook includes the following formats, accessible from your Account page after purchase:

    ePub EPUB The open industry format known for its reflowable content and usability on supported mobile devices.

    Adobe Reader PDF The popular standard, used most often with the free Acrobat® Reader® software.

    This eBook requires no passwords or activation to read. We customize your eBook by discreetly watermarking it with your name, making it uniquely yours.

Description

  • Copyright 2002
  • Dimensions: 7-1/2" x 9-1/8"
  • Pages: 912
  • Edition: 1st
  • eBook (Watermarked)
  • ISBN-10: 0-13-303468-2
  • ISBN-13: 978-0-13-303468-4

The comprehensive, hands-on guide for resolving IP routing problems

  • Understand and overcome common routing problems associated with BGP, IGRP, EIGRP, OSPF, IS-IS, multicasting, and RIP, such as route installation, route advertisement, route redistribution, route summarization, route flap, and neighbor relationships
  • Solve complex IP routing problems through methodical, easy-to-follow flowcharts and step-by-step scenario instructions for troubleshooting
  • Obtain essential troubleshooting skills from detailed case studies by experienced Cisco TAC team members
  • Examine numerous protocol-specific debugging tricks that speed up problem resolution
  • Gain valuable insight into the minds of CCIE engineers as you prepare for the challenging CCIE exams

As the Internet continues to grow exponentially, the need for network engineers to build, maintain, and troubleshoot the growing number of component networks has also increased significantly. IP routing is at the core of Internet technology and expedient troubleshooting of IP routing failures is key to reducing network downtime and crucial for sustaining mission-critical applications carried over the Internet. Though troubleshooting skills are in great demand, few networking professionals possess the knowledge to identify and rectify networking problems quickly and efficiently. Troubleshooting IP Routing Protocols provides working solutions necessary for networking engineers who are pressured to acquire expert-level skills at a moment's notice. This book also serves as an additional study aid for CCIE candidates.

Authored by Cisco Systems engineers in the Cisco Technical Assistance Center (TAC) and the Internet Support Engineering Team who troubleshoot IP routing protocols on a daily basis, Troubleshooting IP Routing Protocols goes through a step-by-step process to solving real-world problems. Based on the authors' combined years of experience, this complete reference alternates between chapters that cover the key aspects of a given routing protocol and chapters that concentrate on the troubleshooting steps an engineer would take to resolve the most common routing problems related to a variety of routing protocols. The book provides extensive, practical coverage of BGP, IGRP, EIGRP, OSPF, IS-IS, multicasting, and RIP as run on Cisco IOS Software network devices.

Troubleshooting IP Routing Protocols offers you a full understanding of invaluable troubleshooting techniques that help keep your network operating at peak performance. Whether you are looking to hone your support skills or to prepare for the challenging CCIE exams, this essential reference shows you how to isolate and resolve common network failures and to sustain optimal network operation.

This book is part of the Cisco CCIE Professional Development Series, which offers expert-level instruction on network design, deployment, and support methodologies to help networking professionals manage complex networks and prepare for CCIE exams.

Sample Content

Table of Contents



Introduction.


1. Understanding IP Routing.

IP Addressing Concepts. IPv4 Address Classes. IPv4 Private Address Space. Subnetting and Variable-Length Subnet Masks. Classless Interdomain Routing. Static and Dynamic Routes. Dynamic Routing. Unicast Versus Multicast IP Routing. Classless Versus Classful IP Routing Protocols. Interior Gateway Protocols Versus Exterior Gateway Protocols. Distance Vector Versus Link-State Protocols. Distance Vector Routing Concepts. Link-State Protocols. Routing Protocol Administrative Distance. Fast Forwarding in Routers. Summary. Review Questions. References.



2. Understanding Routing Information Protocol (RIP).

Metric. Timers. Split Horizon. Split Horizon with Poison Reverse. RIP-1 Packet Format. RIP Behavior. RIP Rules for Sending Updates. RIP Rules for Receiving Updates. Example of Sending Updates. Example of Receiving Updates. Why RIP Doesn't Support Discontiguous Networks. Why RIP Doesn't Support Variable-Length Subnet Masking. Default Routes and RIP. Protocol Extension to RIP. Route Tag. Subnet Mask. Next Hop. Multicast Capability. Authentication. Compatibility Issues. Summary. Review Questions. Further Reading.



3.Troubleshooting RIP.

Flowcharts to Solve Common RIP Problems. Troubleshooting RIP Routes Installation. Problem: RIP Routes Not in the Routing Table. RIP Routes Not in the Routing Table-Cause: Missing or Incorrect network Statement. Debugs and Verification. Solution. RIP Routes Not in the Routing Table-Cause: Layer 1/2 Is Down. Debugs and Verification. Solution. RIP Routes Not in the Routing Table-Cause: distribute-list in Is Blocking the Route. Debugs and Verification. Solution. RIP Routes Not in the Routing Table-Cause: Access List Blocking RIP Source. Address. Debugs and Verification. Solution. RIP Routes Not in the Routing Table-Cause: Access List Blocking RIP Broadcast or Multicast (in Case of RIP-2). Debugs and Verification. Solution. RIP Routes Not in the Routing Table-Cause: Incompatible RIP Version Type. Debugs and Verification. Solution. RIP Routes Not in the Routing Table-Cause: Mismatch Authentication Key (RIP-2). Debugs and Verification. Solution. RIP Routes Not in the Routing Table-Cause: Discontiguous Network. Debugs and Verification. Solution. RIP Routes Not in the Routing Table-Cause: Invalid Source. Debugs and Verification. Solution. RIP Routes Not in the Routing Table-Cause: Layer 2 Problem (Switch, Frame Relay, Other Layer 2 Media). Debugs and Verification. Solution. RIP Routes Not in the Routing Table-Cause: Offset List Has a Large Metric Defined. Debugs and Verification. Solution. RIP Routes Not in the Routing Table-Cause: Routes Reached RIP Hop Count Limit. Debugs and Verification. Solution. Problem: RIP Is Not Installing All Possible Equal-Cost Paths-Cause: maximum-path Command Restricts RIP from Installing More Than One Path. Debugs and Verification. Solution. Troubleshooting RIP Routes Advertisement. Problem: Sender Is Not Advertising RIP Routes. Sender Is Not Advertising RIP Routes-Cause: Missing or Incorrect network Statement. Debugs and Verifications. Solution. Sender Is Not Advertising RIP Routes-Cause: Outgoing Interface Is Down. Debugs and Verification. Solution. Sender Is Not Advertising RIP Routes-Cause: distribute-list out Is Blocking the Route. Debugs and Verification. Solution. Sender Is Not Advertising RIP Routes-Cause: Advertised Network Interface Is Down. Debugs and Verification. Solution. Sender Is Not Advertising RIP Routes-Cause: Outgoing Interface Is Defined Passive. Debugs and Verification. Solution. Sender Is Not Advertising RIP Routes-Cause: Broken Multicast Capability (Frame Relay). Debugs and Verification. Solution. Sender Is Not Advertising RIP Routes-Cause: Misconfigured neighbor Statement. Debugs and Verification. Solution. Sender Is Not Advertising RIP Routes-Cause: Advertised Subnet Is VLSM. Debugs and Verification. Solution. Sender Is Not Advertising RIP Routes-Cause: Split Horizon Is Enabled. Debugs and Verification. Solution. Problem: Subnetted Routes Missing from the Routing Table of R2-Cause: Autosummarization Feature Is Enabled. Debugs and Verification. Solution. Troubleshooting Routes Summarization in RIP. Problem: RIP-2 Routing Table Is Huge-Cause: Autosummarization Is Off. Debugs and Verification. Solution. Problem: RIP-2 Routing Table Is Huge-Cause: ip summary-address Is Not Used. Debugs and Verification. Solution. Troubleshooting RIP Redistribution Problems. Debugs and Verification. Solution. 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. Debugs and Verification. Solution. Problem: RIP Updates Are Not Going Across the Dialer Interface-Cause: Missing broadcast Keyword in a dialer map Statement. Debugs and Verification. Solution. Troubleshooting Routes Flapping Problem in RIP. Debugs and Verification. Solution.



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.



5. Troubleshooting IGRP.

Flowcharts to Solve Common IGRP Problems. Troubleshooting IGRP Route Installation. Problem: IGRP Routes Not in the Routing Table. IGRP Routes Not in the Routing Table-Cause: Missing or Incorrect network Statement. Debugs and Verification. Solution. IGRP Routes Not in the Routing Table-Cause: Layer 1/2 Is Down. Debugs and Verification. Solution. IGRP Routes Not in the Routing Table-Cause: distribute-list in Is Blocking the Route. Debugs and Verification. Solution. IGRP Routes Not in the Routing Table-Cause: Access List Blocking IGRP Source. Address. Debugs and Verification. Solution. IGRP Routes Not in the Routing Table-Cause: Access List Blocking IGRP Broadcast. Debugs and Verification. Solution. IGRP Routes Not in the Routing Table-Cause: Discontiguous Network. Debugs and Verification. Solution. IGRP Routes Not in the Routing Table-Cause: Invalid Source. Debugs and Verification. Solution. IGRP Routes Not in the Routing Table-Cause: Layer 2 Problem (Switch, Frame Relay, Other Layer 2 Media). Debugs and Verification. Solution. IGRP Routes Not in the Routing Table-Cause: Sender's AS Mismatch. Debugs and Verification. Solution. Problem: IGRP Is Not Installing All Possible Equal-Cost Paths-Cause: maximum- paths Restricts IGRP to a Maximum of Four Paths by Default. Debugs and Verification. Solution. Troubleshooting IGRP Routes Advertisement. Problem: Sender Is Not Advertising IGRP Routes. Sender Is Not Advertising IGRP Routes-Cause: Missing or Incorrect network Statement. Debugs and Verification. Solution. Sender Is Not Advertising IGRP Routes-Cause: Outgoing Interface Is Down. Debugs and Verification. Solution. Sender Is Not Advertising IGRP Routes-Cause: distribute-list out Is Blocking the Route. Debugs and Verification. Solution. Sender Is Not Advertising IGRP Routes-Cause: Advertised Network Interface Is Down. Debugs and Verification. Solution. Sender Is Not Advertising IGRP Routes-Cause: Outgoing Interface Is Defined as Passive. Debugs and Verification. Solution. Sender Is Not Advertising IGRP Routes-Cause: Broken Broadcast Capability (Encapsulation Failure in Layer 2). Debugs and Verification. Solution. Sender Is Not Advertising IGRP Routes-Cause: Misconfigured neighbor Statement. Debugs and Verification. Solution. Sender Is Not Advertising IGRP Routes-Cause: Advertised Subnet Is VLSM. Debugs and Verification. Solution. Sender Is Not Advertising IGRP Routes-Cause: Split Horizon Is Enabled. Debugs and Verification. Solution. Problem: Candidate Default Is Not Being Advertised-Cause: ip default-network Command Is Missing. Debugs and Verification. Solution. Troubleshooting IGRP Redistribution Problems. Problem: Redistributed Routes Are Not Getting Installed in the Routing Table-Cause: Metric Is Not Defined During Redistribution into IGRP. Debugs and Verification. Solution. 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. Debugs and Verification. Solution. Problem: IGRP Updates Are Not Going Across the Dialer Interface-Cause: Missing Broadcast Keyword in a dialer map Statement. Debugs and Verification. Solution. Troubleshooting Route Flapping Problem in IGRP. Problem: IGRP Routes Are Flapping-Cause: Packet Drops on Sender's or Receiver's Interface. Debugs and Verification. Solution. Troubleshooting Variance Problem. Problem: IGRP Not Using Unequal-Cost Path for Load Balancing-Cause: variance Command Is Missing or Misconfigured. Debugs and Verification. Solution.



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.



7. Troubleshooting EIGRP.

Troubleshooting EIGRP Neighbor Relationships. Consulting the EIGRP Log for Neighbor Changes. EIGRP Neighbor Problem-Cause: Unidirectional Link. EIGRP Neighbor Problem-Cause: Uncommon Subnet. Misconfiguration of the IP Address on the Interfaces. Primary and Secondary IP Addresses of the Neighboring Interface Don't Match. Switch or Hub Between EIGRP Neighbor Connection Is Misconfigured or Is Leaking. Multicast Packets to Other Ports. EIGRP Neighbor Problem-Cause: Mismatched Masks. EIGRP Neighbor Problem-Cause: Mismatched K Values. EIGRP Neighbor Problem-Cause: Mismatched AS Number. EIGRP Neighbor Problem-Cause: Stuck in Active. Reviewing the EIGRP DUAL Process. Determining Active/Stuck in Active Routes with show ip eigrp topology active. Methodology for Troubleshooting the Stuck in Active Problem. Troubleshooting EIGRP Route Advertisement. EIGRP Is Not Advertising Routes to Neighbors When the Network Administrators Think That It Should. EIGRP Is Not Advertising Routes to Its Neighbors-Cause: Distribute List. EIGRP Is Not Advertising Routes to Its Neighbors-Cause: Discontiguous Networks. EIGRP Is Not Advertising Routes to Neighbors-Cause: Split-Horizon Issues. EIGRP Is Advertising Routes to Neighbors When the Network Administrators Think That It Shouldn't. EIGRP Is Advertising Routes with Unexpected Metric. Troubleshooting EIGRP Route Installation. EIGRP Is Not Installing Routes-Cause: Auto or Manual Summarization. EIGRP Is Not Installing Routes-Cause: Higher Administrative Distance. EIGRP Is Not Installing Routes-Cause: Duplicate Router Ids. Troubleshooting EIGRP Route Flapping. Troubleshooting EIGRP Route Summarization. EIGRP Summarization Route Problem-Cause: Subnetworks of Summary Route Don't Exist in Routing Table. EIGRP Summarization Route Problem-Cause: Too Much Summarization. Troubleshooting EIGRP Redistribution Problems. Troubleshooting EIGRP Dial Backup Problem. EIGRP Error Messages. Summary.



8. Understanding Open Shortest Path First (OSPF).

OSPF Packet Details. Hello Packets. Database Description Packets. Link-State Request Packets. Link-State Update Packets. Link-State Acknowledgment Packet. OSPF LSA Details. Router LSA. Router LSA Example. Network LSA. Network LSA Example. Summary LSA. Summary LSA Example. External LSA. External LSA Example. OSPF Areas. Normal Areas. Stub Areas. Totally Stubby Areas. Not-So-Stubby Areas. Type 7 LSAs. NSSA LSA Example. NSSA Configuration Example. Totally Not-So-Stubby Areas. Filtering in NSSA. Default Routes in NSSA. OSPF Media Types. Multiaccess Media. Point-to-Point Media. Nonbroadcast Multiaccess Media. Broadcast Model. Point-to-Point Model. Point-to-Multipoint Model. Demand Circuits. OSPF Media Type Summary. OSPF Adjacencies. OSPF Down State. OSPF Attempt State. OSPF Init State. OSPF 2-Way State. OSPF Exstart State. OSPF Exchange State. OSPF Loading State. OSPF Full State. Summary. Review Questions.



9. Troubleshooting OSPF.

Flowcharts to Solve Common OSPF Problems. Troubleshooting OSPF. Neighbor Relationships. Problem: OSPF Neighbor List Is Empty. OSPF Neighbor List Is Empty-Cause: OSPF Not Enabled on the Interface. Debugs and Verification. Solution. OSPF Neighbor List Is Empty-Cause: Layer 1/2 Is Down. Debugs and Verification. Solution. OSPF Neighbor List Is Empty-Cause: Interface Is Defined as Passive Under OSPF. Debugs and Verification. Solution. OSPF Neighbor List Is Empty-Cause: Access List Blocking OSPF Hellos on Both Sides. Debugs and Verification. Solution. OSPF Neighbor List Is Empty-Cause: Mismatched Subnet Number/Mask over a Broadcast Link. Debugs and Verification. Solution. OSPF Neighbor List Is Empty-Cause: Mismatched Hello/Dead Intervals. Debugs and Verification. Solution. OSPF Neighbor List Is Empty-Cause: Mismatched Authentication Type. Debugs and Verification. Solution. OSPF Neighbor List Is Empty-Cause: Mismatched Authentication Key. Debugs and Verification. Solution. OSPF Neighbor List Is Empty-Cause: Mismatched Area ID. Debugs and Verification. Solution. OSPF Neighbor List Is Empty-Cause: Mismatched Stub/Transit/NSSA Area Options. Debugs and Verification. Solution. OSPF Neighbor List Is Empty-Cause: OSPF Adjacency Over Secondary IP Address. Debugs and Verification. Solution. OSPF Neighbor List Is Empty-Cause: OSPF Adjacency over Asynchronous Interface. Debugs and Verification. Solution. OSPF Neighbor List Is Empty-Cause: No Network Type or Neighbor Defined over NBMA. Debugs and Verification. Solution. OSPF Neighbor List Is Empty-Cause: Frame Relay/Dialer Interface Missing the broadcast Keyword on Both Sides. Debugs and Verification. Solution. Problem: OSPF Neighbor Stuck in ATTEMPT. OSPF Neighbor Stuck in ATTEMPT-Cause: Misconfigured neighbor Statement. Debugs and Verification. Solution. OSPF Neighbor Stuck in ATTEMPT-Cause: Unicast Connectivity Is Broken on NBMA. Debugs and Verification. Solution. Problem: OSPF Neighbor Stuck in INIT. OSPF Neighbor Stuck in INIT-Cause: Access List on One Side Is Blocking OSPF Hellos. Debugs and Verification. Solution. OSPF Neighbor Stuck in INIT-Cause: Multicast Capabilities Are Broken on One Side (6500 Switch Problem). Debugs and Verification. Solution. OSPF Neighbor Stuck in INIT-Cause: Cause: Authentication Is Enabled Only on One Side. Debugs and Verification. Solution. OSPF Neighbor Stuck in INIT-Cause: The frame-relay map/dialer-map Statement on One Side Is Missing the broadcast Keyword. Debugs and Verification. Solution. OSPF Neighbor Stuck in INIT-Cause: Hellos Are Getting Lost on One Side at Layer 2. Debugs and Verification. Solution. Problem: OSPF Neighbor Stuck in 2-WAY-Cause: Priority 0 Is Configured on All Routers. Debugs and Verification. Solution. Problem: OSPF Neighbor Stuck in EXSTART/EXCHANGE. OSPF Neighbor Stuck in EXSTART/EXCHANGE-Cause: Mismatched Interface MTU. Debugs and Verification. Solutions. OSPF Neighbor Stuck in EXSTART/EXCHANGE-Cause: Duplicate Router IDs on Neighbors. Debugs and Verification. Solution. OSPF Neighbor Stuck in EXSTART/EXCHANGE-Cause: Can't Ping Across with More Than Certain MTU Size. Debugs and Verification. Solution. OSPF Neighbor Stuck in EXSTART/EXCHANGE-Cause: Unicast Connectivity Is Broken. Debugs and Verification. Solutions. OSPF Neighbor Stuck in EXSTART/EXCHANGE-Cause: Network Type Is Point-to-Point Between PRI and BRI/Dialer. Debugs and Verification. Solution. Problem: OSPF Neighbor Stuck in LOADING. OSPF Neighbor Stuck in LOADING-Cause: Mismatched MTU Size. Debugs and Verification. Solution. OSPF Neighbor Stuck in LOADING-Cause: Link-State Request Packet Is Corrupted. Debugs and Verification. Solution. Troubleshooting OSPF Route Advertisement. Problem: OSPF Neighbor Is Not Advertising Routes. OSPF Neighbor Is Not Advertising Routes-Cause: OSPF Not Enabled on the Interface That Is Supposed to Be Advertised. Debugs and Verification. Solution. OSPF Neighbor Is Not Advertising Routes-Cause: Advertising Interface Is Down. Debugs and Verification. Solution. OSPF Neighbor Is Not Advertising Routes-Cause: Secondary Interface Is in a Different Area Than the Primary Interface. Debugs and Verification. Solution. Problem: OSPF Neighbor (ABR) Not Advertising the Summary Route. OSPF Neighbor (ABR) Not Advertising the Summary Route-Cause: Area Is Configured as Totally Stubby Area. Debugs and Verification. Solution. OSPF Neighbor (ABR) Not Advertising the Summary Route-Cause: ABR Is Not Connected to Area 0. Debugs and Verification. Solution. OSPF Neighbor (ABR) Not Advertising the Summary Route-Cause: Discontiguous Area 0. Debugs and Verification. Solution. Problem: OSPF Neighbor Is Not Advertising External Routes. OSPF Neighbor Is Not Advertising External Routes-Cause: Area Is Configured as a Stub Area or NSSA. Debugs and Verification. Solution. OSPF Neighbor Is Not Advertising External Routes-Cause: NSSA ABR Not Translating Type 7 LSAs into Type 5 LSAs. Debugs and Verification. Solution. Problem: OSPF Neighbor Not Advertising Default Routes. OSPF Neighbor Not Advertising Default Routes-Cause: Missing default- information originate Commands. Debugs and Verification. Solution. OSPF Neighbor Not Advertising Default Routes-Cause: Default Route Missing from the Neighbor's Routing Table. Debugs and Verification. Solution. OSPF Neighbor Not Advertising Default Routes-Cause: Neighbor Trying to Inject a Default into a Stub Area. Debugs and Verification. Solution. OSPF Neighbor Not Advertising Default Routes-Cause: NSSA ABR/ASBR Not Originating Type 7 Default. Debugs and Verification. Solution. Troubleshooting OSPF Route Installation. Problem: OSPF Not Installing Any Routes in the Routing Table. OSPF Not Installing Any Routes in the Routing Table-Cause: Network Type Mismatch. Debugs and Verification. Solution. OSPF Not Installing Any Routes in the Routing Table-Cause: IP Addresses Are Flipped in Dual Serial-Connected Routers. Debugs and Verification. Solution. OSPF Not Installing Any Routes in the Routing Table-Cause: One Side Is a Numbered and the Other Side Is an Unnumbered Point-to-Point Link. Debugs and Verification. Solution. OSPF Not Installing Any Routes in the Routing Table-Cause: Distribute List Is Blocking the Route Installation. Debugs and Verification. Solution. OSPF Not Installing Any Routes in the Routing Table-Cause: Broken PVC in a Fully Meshed Frame Relay Network with Broadcast Network Type. Debugs and Verification. Solution. Problem: OSPF Not Installing External Routes in the Routing Table. OSPF Not Installing External Routes in the Routing Table-Cause: Forwarding Address Is Not Known Through the Intra-Area or Interarea Route. Debugs and Verification. Solution. OSPF Not Installing External Routes in the Routing Table-Cause: ABR Not Generating Type 4 Summary LSA. Debugs and Verification. Solution. Troubleshooting Redistribution Problems in OSPF. Problem: OSPF Neighbor Is Not Advertising External Routes. OSPF Neighbor Is Not Advertising External Routes-Cause: Subnets Keyword Missing from the ASBR Configuration. Debugs and Verification. Solution. OSPF Neighbor Is Not Advertising External Routes-Cause: distribute-list out Is Blocking the Routes. Debugs and Verification. Solution. Troubleshooting Route Summarization in OSPF. Problem: Router Is Not Summarizing Interarea Routes-Cause: area range Command Is Not Configured on ABR. Debugs and Verification. Solution. Problem: Router Is Not Summarizing External Routes-Cause: summary-address Command Is Not Configured on ASBR. Debugs and Verification. Solution. Troubleshooting CPUHOG Problems. Problem: CPUHOG Messages During Adjacency Formation-Cause: Router Is Not Running Packet-Pacing Code. Debugs and Verification. Solution. Problem: CPUHOG Messages During LSA Refresh Period-Cause: Router Is Not Running LSA Group-Pacing Code. Debugs and Verification. Solution. Troubleshooting Dial-on-Demand Routing Issues in OSPF. Problem: OSPF Hellos Are Bringing Up the Link-Cause: OSPF Hellos Are Permitted as Interesting Traffic. Debugs and Verification. Solution. Problem: Demand Circuit Keeps Bringing Up the Link. Demand Circuit Keeps Bringing Up the Link-Cause: A Link Flap in the Network. Debugs and Verification. Solution. Demand Circuit Keeps Bringing Up the Link-Cause: Network Type Defined as Broadcast. Debugs and Verification. Solution. Demand Circuit Keeps Bringing Up the Link-Cause: PPP Host Routes Are Getting Redistributed into the OSPF Database. Debugs and Verification. Solution. Demand Circuit Keeps Bringing Up the Link-Cause: One of the Routers Is Not Demand Circuit-Capable. Debugs and Verification. Solution. Troubleshooting SPF Calculation and Route Flapping. SPF Running Constantly-Cause: Interface Flap Within the Network. Debugs and Verification. Solution. SPF Running Constantly-Cause: Neighbor Flap Within the Network. Debugs and Verification. Solution. SPF Running Constantly-Cause: Duplicate Router ID. Debugs and Verification. Solution. 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. Mismatched Area ID. Bad Checksum. OSPF Not Enabled on the Receiving Interface.



10. Understanding Intermediate System-to-Intermediate System (IS-IS).

IS-IS Protocol Overview. IS-IS Routing Protocol. IS-IS Protocol Concepts. IS-IS Nodes, Links, and Areas. Adjacencies. ES-IS Adjacencies. IS-IS Adjacencies. Hierarchical Routing. IS-IS Packets. Generic IS-IS Packet Format. IS-IS Metrics. IS-IS Authentication. ISO CLNP Addressing. NSAP Format. NSAP Examples. Guidelines for Defining NSAP Addresses. IS-IS Link-State Database. Overview of the IS-IS Link-State Database. Flooding and Database Synchronization. Shortest Path First (SPF) Algorithm and IS-IS Route Calculation. Configuring IS-IS for IP Routing. Configuring IS-IS on Point-to-Point Serial Links. show clns protocol Command. show clns neighbors detail Command. show clns interface Command. show isis topology Command. show isis database Command. ATM Configuration Examples. IP Default Route Advertisement. Route Redistribution. IP Route Summarization. Summary. Additional IS-IS Packet Information. IS-IS Packet Fields (Alphabetical Order). Hello Packets. Link-State Packets. Sequence Number Packets. Review Questions. Further Reading.



11. Troubleshooting IS-IS.

Troubleshooting IS-IS Adjacency Problems. Problem 1: Some or All of the Adjacencies Are Not Coming Up. Step 1: Checking for Link Failures. Step 2: Verifying Basic Configuration. Step 3: Checking for Mismatched Level 1 and Level 2 Interfaces. Step 4: Checking for Area Misconfiguration. Step 5: Checking for Misconfigured IP Subnets. Step 6: Check for Duplicate System Ids. Problem 2: Adjacency in INIT State. Mismatched MTU. IS-IS Hello Padding. Misconfigured Authentication. Problem 3: Only ES-IS Adjacency Instead of IS-IS Adjacency Formed. Troubleshooting IS-IS Routing Update Problems. Route Advertisement Problems. Local Routes Not Being Advertised to Remote. Solution Summary. Route Redistribution and Level 2-to-Level 1 Route-Leaking Problems. Route-Flapping Problem. Solution Summary. IS-IS Errors. CLNS ping and traceroute. Case Study: ISDN Configuration Problem. IS-IS Troubleshooting Command Summary. Summary.



12. Understanding Protocol Independent Multicast (PIM).

Fundamentals of IGMP Version 1, IGMP Version 2, and Reverse Path Forwarding. IGMP Version 1. IGMP Version 2. Multicast Forwarding (Reverse Path Forwarding). PIM Dense Mode. PIM Sparse Mode. IGMP and PIM Packet Format. IGMP Packet Format. PIM Packet/Message Formats. Summary. Review Questions.



13. Troubleshooting PIM.

Troubleshooting IGMP Joins. Solution to IGMP Join Problem. Troubleshooting PIM Dense Mode. Solution to PIM Dense Mode Problem. Troubleshooting PIM Sparse Mode. Solution to PIM Sparse Mode Problem. Summary.



14. Understanding Border Gateway Protocol Version 4 (BGP-4).

BGP-4 Protocol Specification and Functionality. Neighbor Relationships. External BGP Neighbor Relationships. Internal BGP Neighbor Relationships. Advertising Routes. Synchronization Rule. Receiving Routes. Policy Control. Policy Control Using BGP Attributes. LOCAL_PREF Attribute. MULTI_EXIT_DISC (MED) Attribute. AS_PATH Attribute. NEXT_HOP Attribute. ORIGIN Attribute. WEIGHT: Cisco Systems, Inc. Proprietary Attribute. Reading BGP Attributes from Cisco IOS Software Output. Use of Route Maps in Policy Control. Using the match ip address Command in a Route Map. Using the match community Command in a Route Map. Using the match as-path Command in a Route Map. Using the set as-path prepend Command in a Route Map. Using the set community Command in a Route Map. Using the set local-preference Command in a Route Map. Using the set metric Command in a Route Map. Using the set weight Command in a Route Map. Policy Control Using filter-list, distribute-list, prefix-list, Communities, and Outbound Route Filtering (ORF). Use of Filter Lists in Policy Control. Use of Distribute Lists in Policy Control. Use of Prefix Lists in Policy Control. Use of Communities in Policy Control. Use of Outbound Route Filtering in Policy Control. Route Dampening. Scaling IBGP in Large Networks-Route Reflectors and Confederations. Route Reflection. AS Confederations. Best-Path Calculation. Summary. Review Questions.



15. Troubleshooting BGP.

Flowcharts to Solve Common BGP Problems. show and debug Commands for BGP-Related Troubleshooting. show ip bgp prefix Command. show ip bgp summary Command. show ip bgp neighbor [address] Command. show ip bgp neighbors [address] [advertised-routes] Command. show ip bgp neighbors [routes] Command. debug ip bgp update [access-list] Command. Standard Access List Usage. Extended Access List Usage. debug ip bgp neighbor-ip-address updates [access-list] Command. Troubleshooting BGP Neighbor Relationships. Problem: Directly Connected External BGP Neighbors Not Initializing. Directly Connected External BGP Neighbors Not Coming Up-Cause: Layer 2 Is Down, Preventing Communication with Directly Connected BGP Neighbor. Debugs and Verification. Solution. Directly Connected External BGP Neighbors Not Coming Up-Cause: Incorrect Neighbor IP Address in BGP Configuration. Debugs and Verification. Solution. Problem: Nondirectly Connected External BGP Neighbors Not Coming Up. Nondirectly Connected External BGP Neighbors Not Coming Up-Cause: Route to the Nondirectly Connected Peer Address Is Missing from the Routing Table. Debugs and Verification. Solution. Nondirectly Connected External BGP Neighbors Not Coming Up-Cause: ebgp- multihop Command Is Missing in BGP Configuration. Debugs and Verification. Solution. Nondirectly Connected External BGP Neighbors Not Coming Up-Cause: update- source interface Command Is Missing. Debugs and Verification. Solution. Problem: Internal BGP Neighbors Not Coming Up. Problem: BGP Neighbors (External and Internal) Not Coming Up-Cause: Interface Access List Blocking BGP Packets. Debugs and Verification. Solution. Troubleshooting BGP Route Advertisement/Origination and Receiving. Problem: BGP Route Not Getting Originated. BGP Route Not Getting Originated-Cause: IP Routing Table Does Not Have a Matching Route. Debugs and Verification. Solution. BGP Route Not Getting Originated-Cause: Configuration Error. Debugs and Verification. Solution. BGP Route Not Getting Originated-Cause: BGP Is Autosummarizing to Classful/ Network Boundary. Debugs and Verification. Solution. Problem in Propagating/Originating BGP Route to IBGP/EBGP Neighbors-Cause: Misconfigured Filters. Debugs and Verification. Solution. Problem in Propagating BGP Route to IBGP Neighbor but Not to EBGP Neighbor- Cause: BGP Route Was from Another IBGP Speaker. Debugs and Verification. Solution. IBGP Full Mesh. Designing a Route-Reflector Model. Designing a Confederation Model. Problem in Propagating IBGP Route to IBGP/EBGP Neighbor-Cause: IBGP Route Was Not Synchronized. Debugs and Verification. Solution. 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 Routes Are Not Synchronized. Debugs and Verification. Solution. IBGP-Learned Route Not Getting Installed in IP Routing Table-Cause: IBGP Next Hop Not Reachable. Debugs and Verification. Solution. Announce the EBGP Next Hop Through an IGP Using a Static Route or Redistribution. Change the Next Hop to an Internal Peering Address. Problem: EBGP-Learned Route Not Getting Installed in IP Routing Table. EBGP-Learned Route Not Getting Installed in IP Routing Table-Cause: BGP Routes Are Dampened. Debugs and Verification. Solution. EBGP-Learned Route Not Getting Installed in IP Routing Table-Cause: BGP Next Hop Not Reachable in Case of Multihop EBGP. Debugs and Verification. Solution. EBGP-Learned Route Not Getting Installed in the Routing Table-Cause: Multiexit Discriminator (MED) Value Is Infinite. Debugs and Verification. Troubleshooting BGP Route-Reflection Issues. Problem: Configuration Mistakes-Cause: Failed to Configure IBGP Neighbor as a Route-Reflector Client. Debugs and Verification. Solution. Problem: Route-Reflector Client Stores an Extra BGP Update-Cause: Client-to-Client Reflection. Debugs and Verification. Solution. Problem: Convergence Time Improvement for RR and Clients-Cause: Use of Peer Groups. Debugs and Verification. Solution. Problem: Loss of Redundancy Between Route Reflectors and Route-Reflector Client -Cause: Cluster List Check in RR Drops Redundant Route from Other RR. Debugs and Verification. Solution. 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. Solution. Problem: Traffic Takes a Different Interface from What Shows in Routing Table- Cause: Next Hop of the Route Is Reachable Through Another Path. Debugs and Verification. Solution. 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. Solution. Request AS 110 to Send the Proper MED for Each Prefix. Don't Accept MED from AS 110. Manually Change LOCAL_PREFERENCE for P1, P2, and P3 at All the Exit Points X, Y, and Z. Problem: Asymmetrical Routing Occurs and Causes a Problem Especially When NAT and Time-Sensitive Applications Are Used-Cause: Outbound and Inbound Advertisement. Debugs and Verification. Solution. Troubleshooting Load-Balancing Scenarios in Small BGP Networks. Problem: Load Balancing and Managing Outbound Traffic from a Single Router When Dualhomed to Same ISP-Cause: BGP Installs Only One Best Path in the Routing Table. Debugs Verification. Solution. 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. Debugs and Verification. Solution. Troubleshooting Inbound IP Traffic Flow Issues Because of BGP Policies. Problem: Multiple Connections Exist to an AS, but All the Traffic Comes in Through One BGP Neighbor, X, in the same AS-Cause: Either BGP Neighbor at X Has a BGP Policy Configured to Make Itself Preferred over the Other Peering Points, or the Networks Are Advertised to Attract Traffic from Only X. Debugs and Verification. Case 1. Case 2. Solution. Problem: Multiple Connections Exist to Several BGP Neighbors, but Most of the Traffic from Internet to 100.100.100.0/24 Always Comes in Through One BGP Neighbor from AS 110-Cause: Route Advertisements for 100.100.100.0/24 in AS 109 Attract Internet Traffic Through That BGP Neighbor in AS 110. Solution. Troubleshooting BGP Best-Path Calculation Issues. Problem: Path with Lowest RID Is Not Chosen as Best. Debugs and Verification. Solution. Problem: Lowest MED Not Selected as Best Path. Debugs and Verification. Solution. Troubleshooting BGP Filtering. Problem: Standard Access List Fails to Capture Subnets. Debugs and Verification. Solution. Problem: Extended Access Lists Fails to Capture the Correct Masked Route. Debugs and Verification. Solution. Extended Access List Solution. Problem: AS_PATH Filtering Using Regular Expressions. Summary.



Appendix.

Answers to Review Questions.

Index.

Updates

Submit Errata

More Information

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.

Overview


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information


To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.

Surveys

Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.

Newsletters

If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information


Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.

Security


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.

Children


This site is not directed to children under the age of 13.

Marketing


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information


If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.

Choice/Opt-out


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information


Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents


California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure


Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.

Links


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact


Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice


We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020