Cisco Systems UBR904 manual Troubleshooting Tips, Understand How Basic Initialization Works

Understand How Basic Initialization Works

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.

Troubleshooting Tips for the Cisco uBR904 Cable Modem 5