• The cable is a stranded cable. • The link partner is a Cisco IP Phone. • The link partner is not IEEE 802.3 compliant. Note We recommend that you keep one end of the cable open when you run TDR on a port. The cable length and other relevant status information are obtained correctly when the cables are open at one end. You can do this either by physically removing the cable at one end or shutting it at one end and reading the result at the other end. Go to Running TDR and Displaying the Results, on page 21 to know the TDR commands. Debug Commands Caution Because debugging output is assigned high priority in the CPU process, it can render the system unusable.
For this reason, use debug commands only to troubleshoot specific problems or during troubleshooting sessions with Cisco technical support staff. It is best to use debug commands during periods of lower network traffic and fewer users. Debugging during these periods decreases the likelihood that increased debug command processing overhead will affect system use. All debug commands are entered in privileged EXEC mode, and most debug commands take no arguments. System Report System reports or crashinfo files save information that helps Cisco technical support representatives to debug problems that caused the Cisco IOS image to fail (crash).
It is necessary to quickly and reliably collect critical crash information with high fidelity and integrity. Further, it is necessary to collect this information and bundle it in a way that it can be associated or identified with a specific crash occurrence. System reports are generated in these situations: • In case of a switch failure—A system report is generated on the member that failed; reports are not generated on other members in the stack. • In case of a switchover—System reports are generated only on high availability (HA) member switches. Reports are not generated for non-HA members. The system does not generate reports in case of a reload.
During a process crash, the following is collected locally from the switch: 1. Full process core 2. Tracelogs 3. IOS syslogs (not guaranteed in case of non-active crashes) 4. System process information Troubleshooting the Software Configuration Debug Commands Troubleshooting the Software Configuration 6