Connect to the Cable Modem

 

.

 

 

 

 

Table 1

Cable Modem Initialization Sequences and Events

 

 

 

 

 

 

 

Sequence

Event

Description

 

 

 

 

 

 

1

Scan for a downstream channel and

The cable modem acquires a downstream channel from the

 

 

 

establish synchronization with the

headend, saves the last operational frequency in non-volatile

 

 

 

headend Cisco uBR7246.

memory, and tries to reacquire the saved downstream

 

 

 

 

channel the next time a request is made.

 

 

 

 

An ideal downstream signal is one that synchronizes QAM

 

 

 

 

symbol timing, FEC framing, MPEG packetization, and

 

 

 

 

recognizes downstream sync MAC layer messages.

 

 

 

 

 

 

2

Obtain upsteam channel parameters.

The cable modem waits for an upstream channel descriptor

 

 

 

 

messages (UCD) from the headend Cisco uBR7246. This is

 

 

 

 

done to retrieve transmission parameters for the upstream

 

 

 

 

channel.

 

 

 

 

 

 

3

Start ranging for power adjustments.

The ranging process adjusts cable modem’s transmit power.

 

 

 

 

The cable modem performs ranging in stages, ranging state

 

 

 

 

1 and ranging state 2.

 

 

 

 

 

 

4

Establish IP connectivity.

The cable modem invokes DHCP requests to obtain an IP

 

 

 

 

address, which is needed for IP connectivity. The DHCP

 

request also includes the name of a file that contains additional configuration parameters, the TFTP server’s address, and the Time of Day (TOD) server’s address.

5Establish the time of day.

The Cisco uBR904 cable modem accesses the TOD server for the current date and time, which is used to create time stamps for logged events (such as those displayed in the MAC log file).

6

Establish security.

Keys for privacy are exchanged between the cable modem

 

 

and the CMTS (the Cisco uBR7246 cable router).

 

 

 

7

Transfer operational parameters.

After the DHCP and security operations are successful, the

 

 

cable modem downloads operational parameters from a

 

 

configuration file stored on a cable company’s TFTP server.

 

 

 

8

Perform registration.

The cable modem registers with the headend

 

 

Cisco uBR7246. The cable modem is authorized to forward

 

 

traffic into the cable network after the cable modem is

 

 

initialized, authenticated, and configured.

 

 

Note The Cisco uBR904 cable modem supports baseline

 

 

privacy in Cisco IOS Release 11.3(5)NA and later.

 

 

 

9

Comply with baseline privacy.

Link level encryption keys are exchanged between the

 

 

headend and the cable modem.

 

 

 

10

Enter the operational maintenance

As soon as the cable modem is completely up and running,

 

state.

it enters operational maintenance state.

 

 

 

Connect to the Cable Modem

Telnet to the IP address assigned to the cable interface or Ethernet interface. If the interface is not up, you need to access the Cisco IOS software via the RJ-45 console port, which is a physical port on the back of the cable modem.

Because the MAC log file only holds a snapshot of 1023 entries at a time, you should try to display the cable modem’s log file within 5 minutes of when the reset or problem occurs.

Troubleshooting Tips for the Cisco uBR904 Cable Modem 7

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Cisco Systems UBR904 manual Connect to the Cable Modem

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.