Understand How Basic Initialization Works
Troubleshooting Tips for the Cisco uBR904 Cable Modem 5
Troubleshooting Tips
Perform the following steps to troubleshoot a cable modem:
• Step 1—Understand How Basic Initialization Works
• Step 2—Connect to the Cable Modem
• Step 3—Display the Cable Modem’s MAC Log File
• Step 4—Interpret the MAC Log File and Take Action
• Step 5—(Optional) Use Additional Troubleshooting Commands
Understand How Basic Initialization Works
Before you troubleshoot a cable modem, you should be familiar with the cable modem initialization
process. See Figure 2 and Table 1. Understanding this flowchart and sequence of events helps you
determine where and why connections fail.
The sequence numbers shown in Figure 2 are explained in Table 1, which appears after the
illustration. The cable modem will complete all the steps in this flowchart each time the cable
modem needs to reestablish ranging and registration with the CMTS.
