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Chapter 8
Monitoring & Troubleshooting an OSPF Network “Perseverance: The difference between a successful person and others is not a lack of strength, not a lack of knowledge, but rather a lack of will.”—Successories This chapter builds upon the design theories and processes discussed in Chapter 7, “Designing & Implementing an OSPF Network.” This chapter assumes that you have designed and implemented an OSPF network as detailed in the process in Chapter 7. The basis for this chapter is how to go about monitoring and ensuring OSPF is operating correctly and what to do if it is not. There are certain troubleshooting procedures and techniques that you can use to determine the causes of a network problem, which are covered as well. This chapter consists of three major sections, which are as follows: - • Monitoring OSPF. This section covers how to go about determining if OSPF is configuring and operating as you designed it to. This is one of the most important areas of the book. It is essential to master the techniques and commands used to this section. By doing so, you will be able to more effectively implement, monitor, and manage your OSPF network.
- • Troubleshooting OSPF. This section provides you with the techniques needed to troubleshoot more effectively when an OSPF-related network problem occurs. This section also assists you in developing your network and its related management structure to allow you to reduce the length of any network problem. This information is supplemented by in-depth discussions on various network troubleshooting commands.
- • Cisco Technical Support. This section explores the many different ways of finding and gaining access to the resources available. These resources include deciphering Cisco’s Connection Online (CCO) and how technical support information is available for engineers at all levels of knowledge.
Monitoring OSPF Now that your OSPF network has been designed and implemented, or will soon be implemented, there are some important questions to ask yourself before proceeding: - • Is OSPF operating properly and in accordance with your design?
- • Are you sure or unsure?
- • How and why are you sure or unsure?
- • What do you know about how OSPF is operating?
The true test of your design will be in how well it operates. This section will concentrate on the methods needed to determine how well the OSPF design is operating and provide you with the tools necessary to answer the previously cited questions. Many people follow the belief that the network “must be up,” but I think that going a step further is more accurate in that the network “must be up and operational.” Monitoring the Operation of OSPF Having the ability and knowledge to properly monitor OSPF will be a crucial part of your network’s success or failure. An essential requirement to your network operation is that the status of your routers and their routing protocols are monitored to ensure network availability for all users. Although many different types of network management platforms are available to assist you in this endeavor, there are tools to make this management task easier. At some level, every management platform will be based upon the following three methods of monitoring: - • SHOW commands
- • Router SYSLOG files
- • SNMP and MIBs
Each of these three monitoring techniques requires a different area of understanding in order to use it. This chapter discusses the various OSPF SHOW commands and how to configure the Router SYSLOG file to provide you with information regarding OSPF. Chapter 9, “Managing Your OSPF Network,” discusses SNMP and OSPF MIBs. OSPF SHOW Commands This section is similar to the OSPF configuration commands provided in Chapter 6, “Advanced OSPF Design Concepts.” This section has a list of the most useful OSPF SHOW commands and definitions of their output. This information is essential for you as you begin implementing your network design. By this point in your network implementation, you should be ready to see if your OSPF network is working as you designed it to. This section discusses many of the SHOW commands available for use within Cisco routers. Before going on, review the OSPF actions that will demand resources from the router, as illustrated in Figure 8-1. 
Figure 8-1 OSPF resource utilization.
show ip ospf ? Command The show ip ospf ? command provides you with the means to determine exactly what OSPF SHOW commands are available for you within a Cisco router. This is very useful, as available commands differ per Cisco IOS release. Any time you use a question mark, it invokes a help menu as shown below of the available commands. Example: OSPF_Router# show ip ospf ? <1-4294967295> Process ID number(s) that are running on the router border-routers Border and Boundary Router Information database LSA Database summary interface Interface information neighbor Neighbor list request-list Link state request list retransmission-list Link state retransmission list summary-address Summary-address redistribution Information virtual-links Virtual link information show ip ospf Command The show ip ospf command displays a variety of general information about the routing process. To display general information about OSPF routing processes, use the show ip ospf EXEC command. The syntax for this command is as follows: show ip ospf [process-id] Syntax Description: - process-id. If the optional process-id argument (which represents the Process ID) is included, only information for the specified OSPF routing process is included.
Usage Guidelines: The full SPF algorithm is run only when there is a topology change, as expressed in a router link-state advertisements (LSAs), not for summary LSAs; they cause a partial spf to be run. This command can be used to determine the number of times the SPF algorithm has been executed. It also shows the link-state update interval, assuming no topological changes have occurred.
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