Troubleshooting at the control plane is dependent on the specific protocol or technology that is being problematic. While generic commands to be used to troubleshoot control plane issues, such as using the debug ip routing command to troubleshoot routing protocol issues, for the most part protocol-specific commands should be used to troubleshoot control plane problems. Because the troubleshooting of routing protocols, such as EIGRP, OSPF and BGP has already been described earlier in this guide, for brevity and to avoid being repetitive, routing protocol troubleshooting will not included in this chapter. The same is also applicable for Spanning Tree Protocol troubleshooting, which was also described in detail earlier in this guide.
Troubleshooting for additional control plane features such as Dynamic ARP Inspection and DHCP Snooping primarily centers on configuration. If the features are not implemented correctly, they will not work as expected. Therefore, from a troubleshooting perspective, you should ensure that you understand how these features work. You can then determine if the feature is not working correctly because of a misconfiguration or other issue, such as software or hardware errors or bugs for example.