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

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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

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Contents Benefits Feature SummaryList of Terms Feature SummaryList of Terms PrerequisitesSupported MIBs and RFCs Cmts to Cable Modem Network Topology Cmts to Cable Modem Network TopologyUnderstand How Basic Initialization Works Troubleshooting TipsUnderstand How Basic Initialization Works Cable Modem Initialization Flowchart Troubleshooting TipsConnect to the Cable Modem UBR904# show controller cable-modem 0 mac log Display the Cable Modem’s MAC Log FileDisplay the Cable Modem’s MAC Log File Interpret the MAC Log File and Take Action CmaclogresetfromdriverEvent 1-Wait for the Link to Come Up UBR904# show controller cable-modem 0 mac ?Interpret the MAC Log File and Take Action Event 3-Obtain Upstream Parameters Event 4-Start Ranging for Power AdjustmentsEvent 7-Establish Security Event 5-Establish IP ConnectivityEvent 6-Establish the Time of Day Event 10-Comply with Baseline Privacy Event 8-Transfer Operational ParametersEvent 9-Perform Registration Event 11-Enter the Maintenance State Use Additional Troubleshooting CommandsUse Additional Troubleshooting Commands Command PurposeCommand Reference Command ReferenceShow controller cable-modem Command ModeSyntax Description Usage GuidelinesRelated Commands UBR904# show controller cable-modem 0 bpkm Show controller cable-modem bpkmShow controller cable-modem bpkm UBR904# show controller cable-modem 0 des downstream des Show controller cable-modem desShow controller cable-modem des Dsmacdafilters Show controller cable-modem filtersShow controller cable-modem filters Lookup table is displayed in the following example Show controller cable-modem lookup-tableShow controller cable-modem lookup-table Show controller cable-modem mac Errors014313 528315.936 Cmaclogadjustrangingoffset 014308 528311.396 CmacloginitialrangingminislotsShow controller cable-modem mac 014259 528302.046 CmaclogdriverinitidbshutdownCmaclogresetdhcpwatchdogexpired CmaclogwatchdogtimerUBR904# show controller cable-modem 0 mac errors CmaclogdhcpprocesskilledUBR904# show controller cable-modem 0 mac resets Possible but Uncommon Cable Interface Reset CausesSample Displays Message DescriptionCmaclogresetchangeuswatchdogexpired CmaclogresetprivacywatchdogexpiredCmaclogresetsecuritywatchdogexpired CmaclogresetallfrequenciessearchedCmaclogresetunabletosetmibobject CmaclogresetdstunerwatchdogInterrupts Irqpend=0x0018, irqmask=0x00E7 True UBR904# show controller cable-modem 0 mac stateDS ID 64QAMBurst Descriptor Interval Usage Code US IDRanging Backoff Start D12=FFD3FFE0 Show controller cable-modem phyD11=FFD3FFAD CC CC CC CC CC 0D 0D CC CC CC CC CC CC CC CC 0D Show controller cable-modem phyShow controller cable-modem tuner Show controller cable-modem tuner Accounting Show interface cable-modemUBR904# show int cable-modem 0 accounting Show interface cable-modemARP UBR904# show int cable-modem 0 countersDebug Commands Debug CommandsDebug cable-modem bpkm Debug cable-modem bpkmBpkm UBR904# debug cable bpkmRelated Commands UBR904# debug cable-modem bridge Debug cable-modem bridgeDebug cable-modem bridge Debug cable-modem error Debug cable-modem errorSample Debug Cable-Modem Error Output UBR904# debug cable-modem interrupts Debug cable-modem interruptsDebug cable-modem interrupts Debug cable-modem mac UBR904# debug cable-modem mac log Debug cable-modem macSample Debug Cable-Modem Mac Log Output Debug cable mac messages UBR904# debug cable mac logUBR904# debug cable mac log verbose CC 0D RsvdMAC Management Message Header EhdrDebug cable-modem map Debug cable-modem mapDebug cable-modem map What to do Next What to do Next
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UBR904 specifications

The Cisco UBR904 is a versatile broadband access device designed to deliver high-speed internet and data services in various deployment scenarios, particularly suitable for cable operators and service providers. This device allows operators to provide broadband services over a wide area, utilizing advanced technologies to ensure reliability and performance.

One of the key features of the UBR904 is its capability to support multiple channels for upstream and downstream communication, allowing for greater bandwidth and improved network performance. With its integrated DOCSIS (Data Over Cable Service Interface Specification) compliance, the UBR904 enables operators to leverage existing coaxial cable infrastructures to deliver data services efficiently. This makes it an ideal choice for operators looking to expand their service offerings without the need for extensive infrastructure changes.

Equipped with a powerful processor and ample memory, the UBR904 is designed for high throughput and low latency, supporting IP data services, voice services, and video on demand. It utilizes advanced modulation techniques and error correction algorithms that enhance data transmission efficiency and reliability. This results in a robust platform capable of meeting the demands of high-density areas while accommodating future growth.

The UBR904 also features flexible management capabilities. It includes support for SNMP (Simple Network Management Protocol), enabling operators to monitor and manage network performance effectively. The device can be easily configured through a graphical user interface or command-line interface, providing system administrators with the tools needed for straightforward deployment and maintenance.

In addition to its core functionalities, the UBR904 integrates security features to protect network traffic and ensure user data integrity. This includes capabilities for secure tunneling and access control lists, which enhance the security of the broadband connection.

Furthermore, the Cisco UBR904 is designed with scalability in mind. Operators can easily scale their networks by adding additional modules or interfaces as demand grows. This ensures that the UBR904 can meet the evolving needs of service providers without necessitating a complete hardware overhaul.

In summary, the Cisco UBR904 is a robust, feature-rich broadband access device that combines high performance, advanced technologies, and scalability, making it an excellent choice for operators looking to deliver high-speed internet and data services across diverse environments. Its ease of use and extensive management features further enhance its appeal, positioning it as a key player in the broadband access market.