The field CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND tells you what frequency the cable modem will scan for. The field CMAC_LOG_WILL_SEARCH_SAVED_DS_FREQUENCY tells you the frequency the cable modem locked onto and saved to NVRAM (for future recall). The field
communicates the same information. The field indicates that the scanning and synchronization was
Event 2Scan for a Downstream Channel then Synchronize
Different geographical regions and different cable plants use different frequency bands. The Cisco uBR904 cable modem uses a built-in default frequency scanning feature to address this issue. After the cable modem finds a successful downstream frequency channel, it saves the channel to NVRAM. The cable modem recalls this value the next time it needs to synchronize its frequency.
successful.
CMAC_LOG_DS_CHANNEL_SCAN_COMPLETED
CMAC_LOG_DS_64QAM_LOCK_ACQUIRED

Interpret the MAC Log File and Take Action

508144.348

CMAC_LOG_STATE_CHANGE

ds_channel_scanning_state

508144.350

CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND

88/453000000/855000000/6000000

508144.354

CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND

89/93000000/105000000/6000000

508144.356

CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND

90/111250000/117250000/6000000

508144.360

CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND

91/231012500/327012500/6000000

508144.362

CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND

92/333015000/333015000/6000000

508144.366

CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND

93/339012500/399012500/6000000

508144.370

CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND

94/405000000/447000000/6000000

508144.372

CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND

95/123015000/129015000/6000000

508144.376

CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND

96/135012500/135012500/6000000

508144.380

CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND

97/141000000/171000000/6000000

508144.382

CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND

98/219000000/225000000/6000000

508144.386

CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND

99/177000000/213000000/6000000

508144.390

CMAC_LOG_WILL_SEARCH_SAVED_DS_FREQUENCY

699000000

508145.540

CMAC_LOG_UCD_MSG_RCVD

3

508146.120

CMAC_LOG_DS_64QAM_LOCK_ACQUIRED

699000000

508146.122

CMAC_LOG_DS_CHANNEL_SCAN_COMPLETED

 

A frequency band is a group of adjacent channels. These bands are numbered from 88 to 99. Each band has starting and ending digital carrier frequencies and a 6 MHz step size. For example, a search of EIA channels 95-97 is specified using band 89. The starting frequency is 93 Mhz, the ending frequency is 105 Mhz.

The cable modem’s default frequency bands correspond to the North American EIA CATV channel plan for 6 MHz channel slots between 90 MHz and 858 MHz. For example, EIA channel 95 occupies the slot 90-96 MHz. The digital carrier frequency is specified as the center frequency of 93 MHz.

Channel 95 is usually specified using the analog video carrier frequency of 91.25 Mhz, which lies 1.75 Mhz below the center of the slot.

The search table is arranged so that the first frequencies tried are above 450 Mhz. Because many CATV systems have been upgraded from 450 MHz to 750 MHz coaxial cable, digital channels have a high chance of being assigned in the new spectrum. The search table omits channels below 90 MHz and above 860 MHz since the DOCSIS specification does not mandate their coverage.

Some CATV systems use alternative frequency plans such as the IRC (Incrementally Related Carrier) and HRC (Harmonically Related Carrier) plans. Most of the IRC channel slots overlap the EIA plan. The HRC plan is not supported by Cisco’s cable modems since so few cable plants are using this plan.

Troubleshooting Tips for the Cisco uBR904 Cable Modem 11

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Cisco Systems UBR904 manual Interpret the MAC Log File and Take Action, Cmaclogwillsearchdsfrequencyband

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.