List of Figures

Chapter 1: Introduction to Troubleshooting

Figure 1.1: A complex network.

Figure 1.2: The network architecture of Spacesoft Inc.

Figure 1.3: The Cisco hierarchical model.

Figure 1.4: Position of layers in the OSI model.

Figure 1.5: The data movement from source to destination in the OSI model.

Figure 1.6: The layered architecture of the TCP/IP model.

Figure 1.7: Mapping the OSI and TCP/IP models.

Figure 1.8: Cisco’s problem resolution model.

Figure 1.9: Diagram of an internetwork.

Chapter 2: Protocols and Their Characteristics

Figure 2.1: The handshake process in a connection-oriented behavior.

Figure 2.2: The PPP frame format.

Figure 2.3: The different phases of a point-to-point link connection.

Figure 2.4: Functions of primary and secondary nodes.

Figure 2.5: The frame format of the SDLC protocol.

Figure 2.6: The HDLC Frame Structure

Figure 2.7: The IP header datagram.

Figure 2.8: Allocation of IP addresses.

Figure 2.9: The addressing format of Class A.

Figure 2.10: The addressing format of Class B.

Figure 2.11: The addressing format of Class C.

Figure 2.12: Internetworking of different classes of an IP network.

Figure 2.13: The header format of TCP.

Figure 2.14: The message format of IGRP.

Figure 2.15: The packet format of EIGRP.

Chapter 3: Diagnostic Mechanisms

Figure 3.1: The output of the show version diagnostic command.

Figure 3.2: The output of the show startup-config diagnostic command.

Figure 3.3: The output of the show running-config diagnostic command.

Figure 3.4: The output of the show interfaces diagnostic command.

Figure 3.5: The output of the show controllers diagnostic command.

Figure 3.6: The output of the show flash diagnostic command.

Figure 3.7: The output of the show buffers diagnostic command.

Figure 3.8: The output of the show memory diagnostic command.

Figure 3.9: The output of the show process CPU diagnostic command.

Figure 3.10: The output of the show stack diagnostic command.

Figure 3.11: The output of the show cdp neighbors diagnostic command.

Figure 3.12: The output of the show logging diagnostic command.

Figure 3.13: The output of the ping command.

Figure 3.14: The output of the debug cdp packets diagnostic command.

Figure 3.15: The output of the trace diagnostic command.

Figure 3.16: The output of the show cdp diagnostic command.

Figure 3.17: The output of the show cdp neighbors diagnostic command.

Chapter 4: Troubleshooting Tools

Figure 4.1: The output of the debug diagnostic command.

Figure 4.2: The output of the show process cpu diagnostic command.

Figure 4.3: The SNMP framework has two managed devices.

Figure 4.4: Output of a successful ping command echoing data packets.

Figure 4.5: The trace diagnostic command showing its output.

Chapter 5: Troubleshooting TCP/IP

Figure 5.1: Testing TCP/IP network connectivity using the ping command.

Figure 5.2: Problem isolation for a network problem.

Figure 5.3: The TCP/IP network diagram of Define Solutions.

Chapter 6: Troubleshooting RIP Environments

Figure 6.1: A routing scenario with four interconnected routers.

Figure 6.2: Passive interface configuration in Router1.

Figure 6.3: Redundant link between Router1 and Router4.

Figure 6.4: RIPv2 configuration.

Figure 6.5: Scenario depicting a discontiguous network.

Figure 6.6: Scenario in which Router1 is configured with RIPv1 and Router2 is configured with RIPv2.

Figure 6.7: Scenario in which Router1 is not sending any routing updates to its connected neighbor.

Figure 6.8: Scenario to describe the time required to build a consistent routing table across four routers.

Figure 6.9: Unavailability of one of the networks connected to Router3 for the understanding of route poisoning.

Figure 6.10: Mechanism of the triggered update.

Chapter 7: Troubleshooting IGRP Routing Environments

Figure 7.1: A network configured with the IGRP routing protocol.

Figure 7.2: An IGRP network showing passive interface configuration at R5.

Figure 7.3: An IGRP routing scenario depicting equal cost paths.

Figure 7.4: An IGRP network showing mismatch in ASN.

Figure 7.5: An IGRP network depicting a scenario of missing update packets.

Figure 7.6: An IGRP case study.

Chapter 8: Troubleshooting EIGRP Routing Environments

Figure 8.1: Part of an EIGRP network with show commands at B2.

Figure 8.2: Part of an EIGRP network with debug commands at B2.

Figure 8.3: An EIGRP network with possibility for misconfigurations.

Figure 8.4: An EIGRP network depicting neighbor formation problems.

Figure 8.5: An EIGRP network depicting route problems.

Figure 8.6: An EIGRP network depicting metric problems.

Figure 8.7: An EIGRP network showing the SIA state.

Figure 8.8: An EIGRP network showing redistribution problems.

Figure 8.9: An EIGRP routing environment.

Chapter 9: Troubleshooting OSPF Routing Environments

Figure 9.1: An OSPF enabled network.

Figure 9.2: An OSPF network.

Figure 9.3: An OSPF network showing routers A1 and A2.

Figure 9.4: An OSPF network.

Figure 9.5: A Frame Relay NBMA network in OSPF.

Figure 9.6: Part of an OSPF network showing Area 0 and Area 5.

Figure 9.7: Example showing a network configured with OSPF and RIP routing protocols.

Figure 9.8: A network configured with OSPF and EIGRP routing protocols.

Chapter 10: Troubleshooting IS-IS Routing Environments

Figure 10.1: A network configured with an IS-IS routing protocol.

Figure 10.2: An IS-IS network depicting a NET misconfiguration scenario.

Figure 10.3: Calculation of NET value in IS-IS networks.

Figure 10.4: An IS-IS network depicting an L2 router problem.

Figure 10.5: Redistribution between OSPF and IS-IS routing domains in a network.

Figure 10.6: An IS-IS network scenario.

Chapter 11: Troubleshooting BGP for Routing Environments

Figure 11.1: Part of a BGP network showing routers A1, A2, A3, and B1.

Figure 11.2: Part of a BGP network showing routers B1, B2, and C1.

Figure 11.3: A BGP network depicting a neighbor relationship problem.

Figure 11.4: A BGP network depicting a BGP route advertisement problem.

Figure 11.5: BGP running between A1 and B1 in AS5555 and AS6666.

Figure 11.6: A BGP network showing misconfiguration problems between AS5555 and AS6666.

Figure 11.7: A BGP network depicting problems related to attributes.

Figure 11.8: BGP route dampening occurs between AS5555 and AS6666.

Figure 11.9: A BGP network showing a redistribution problem.

Figure 11.10: A BGP network depicting the BGP communities’ problem.

Figure 11.11: A BGP network depicting multihoming and loadsharing problems.

Figure 11.12: A scenario showing a complex BGP network.

Chapter 12: Troubleshooting Redistribution Routing Environments

Figure 12.1: Redistribution scenario with routing protocols EIGRP and OSPF.

Figure 12.2: Redistribution scenario running OSPF and RIP.

Figure 12.3: Redistribution scenario with static routing between B1 and B2.

Figure 12.4: Routing environment with no dynamic routing protocol enabled.

Figure 12.5: Routing scenario amongst IS-IS and OSPF protocols.

Figure 12.6: A complex routing scenario running RIP and EIGRP.