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CCNP TSHOOT Certification Guide: Advanced Cisco Catalyst Switch Troubleshooting


  1. "Do I Know This Already?" Quiz
  2. Foundation Topics
  3. Exam Preparation Tasks

Chapter Description

This chapter focuses on troubleshooting Cisco Catalyst Switch platforms in preparation for the CCNP TSHOOT exam 642-832.

Exam Preparation Tasks

Review All Key Topics

Review the most important topics from inside the chapter, noted with the Key Topics icon in the outer margin of the page. Table 5-6 lists these key topics and the page numbers where each is found.


Table 5-6. Key Topics for Chapter 5

Key Topic Element


Page Number

Table 5-2

Similarities and differences between routers and Layer 3 switches


Table 5-3

Router data plane verification commands


Example 5-3

SVI configuration



Differences between SVIs and routed ports


Examples 5-5 and 5-6

HSRP configuration


Figure 5-6

Basic VRRP Operation


Figure 5-7

Basic GLBP Operation


Table 5-4

Comparing HSRP, VRRP, and GLBP



Cisco Catalyst hardware components


Table 5-5

Errors in the show interfaces interface_id counters errors command



Reasons why a packet might be punted from a TCAM to its CPU


Example 5-19

Output from the show processes cpu command on a Cisco Catalyst 3550 Series switch


Complete Tables and Lists from Memory

Print a copy of Appendix B, "Memory Tables," (found on the CD) or at least the section for this chapter, and complete the tables and lists from memory. Appendix C, "Memory Tables Answer Key," also on the CD, includes completed tables and lists to check your work.

Define Key Terms

Define the following key terms from this chapter, and check your answers in the Glossary:

  • Layer 3 switch, switched virtual interface (SVI), Hot Standby Router Protocol (HSRP), Virtual Router Redundancy Protocol (VRRP), Global Load Balancing Protocol (GLBP), control plane, backplane, Ternary Content Addressable Memory (TCAM)

Command Reference to Check Your Memory

This section includes the most important configuration and EXEC commands covered in this chapter. To determine how well you have memorized the commands as a side effect of your other studies, cover the left side of Tables 5-7 and 5-8 with a piece of paper, read the descriptions on the right side, and see whether you remember the command.

Table 5-7. Chapter 5 Configuration Command Reference



standby group ip virtual-ip-address

Interface configuration mode command, used to specify the virtual IP address to be serviced by an HSRP group.

standby group priority priority

Interface configuration mode command, used to configure an interface's HSRP priority (which defaults to 100).

standby group preempt

Interface configuration mode command, which causes a previously active HSRP router to regain its active status if it becomes available.

mdix auto

Interface configuration mode command for a switch that allows the switch port to automatically detect and adjust to the connected cable type (that is, either straight-through or cross-over).

Table 5-8. Chapter 5 EXEC Command Reference



show standby interface-id group

Displays the HSRP configuration applied to a specified interface in a specified HSRP group.

show standby brief

Provides a summary view of a router's HSRP configuration.

debug standby

Shows HSRP state changes and information about sent and received HSRP packets.

show vrrp brief

Provides a summary view of a router's VRRP configuration.

show glbp brief

Provides a summary view of a router's GLBP configuration.

show ip cef

Displays the router's Layer 3 forwarding information, in addition to multicast, broadcast, and local IP addresses.

show adjacency

Verifies that a valid adjacency exists for a connected host.

show tcam inacl tcam_number statistics

A Cisco Catalyst 3550 Series switch command that displays the amount of TCAM memory allocated and used for inbound access control lists.

show platform ip unicast counts

A Cisco Catalyst 3750 Series switch command that can be used to see if a TCAM allocation has failed.

show controllers cpu-interface

A Cisco Catalyst 3750 Series switch command that can be used to display a count of packets being forwarded to a switch's CPU.