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Cable Modem Termination Systems (CMTS): Architecture, Configuration, and Troubleshooting

Community Manager
Community Manager

Read the bioWith Eric Bautista

Welcome to the Cisco Support Community Ask the Expert conversation. This is an opportunity to get an overview of the Cisco Cable Modem Termination System (CMTS) platforms and the uBR product family.

Eric Bautista is a customer support engineer at the Cisco Technical Assistance Center (TAC.) He is responsible for supporting the Cisco uBR CMTS platforms. He has 3.5 years of experience in cable technology. Previous to his current role, Bautista supported Cisco WAN and optical technologies, including QoS and SONET/SDH.

Remember to use the rating system to let Eric know if you have received an adequate response.

Eric might not be able to answer each question due to the volume expected during this event.

Remember that you can continue the conversation on the Service Provider sub-community discussion forum shortly after the event. This event lasts through September 21, 2012. Visit this forum often to view responses to your questions and the questions of other community members.

Webcast Related links:

21 Replies 21

Community Manager
Community Manager

Another question

What are the main benefits of DOCSIS 3.0 with IPv6?

Is there a specific benefit that you would like information about?  DOCSIS 3.0 and IPv6 on Cable are specific features on their own.  You can certainly use them together but it's not necessary. 

Perhaps this link will help.

Community Manager
Community Manager

Last question from the live event that was not answered:

Is the wide band SPA only for 5x20 and 20x20 cards w/RFGW1 or 10?

Hi Eric,

I have some questions about CMTS, Is this device used to terminate any signals that come from network?

What is the main purpose of this device?


Hi Fahad,

CMTS stands for Cable Modem Termination System.  In other words, all the Cable Modems in a specific market will eventully terminate or aggregate to a CMTS device.

CableLabs defines a CMTS as follows:

     The CMTS connects the operator's back office and core network

      with the HFC network. Its main function is to forward packets between

      these two domains, and optionally forward packets between upstream

     and downstream channels on the HFC network.

The HFC that they refer to is the Hybrid Fiber Coaxial network.  Slide #12 in the presentation illustrates this.

The Cisco Wideband SPA is only supported in the uBR10k platform.

The Cisco Wideband SPA is a single-wide, half-height shared port adapter that provides DOCSIS Network formatting to downstream data packets. The Cisco Wideband SPA is used for downstream data traffic only and is a key component for the DOCSIS 3.0 Downstream Channel Bonding and DOCSIS M-CMTS network architectures.

This means that you will need an external EQAM device which will receive the data from the Wideband SPA and

perform QAM modulation and RF upconversion.


Can I use diagnostic software (ubr10k-fdiagslc-mz.7_0.bin) to troubleshoot UBR-MC3GX60V? If not, kindly advise the version that will work. Thank you in advance.

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