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DOCSIS PNM – Something Really Interesting!

Post 99 of 192

DOCSIS PNM - Get Excited!

Awhile back I wrote an article about DOCSIS Proactive Network Maintenance (PNM).  Not only did I find this technology fascinating I decided to really get involved with PNM.  I will also be speaking at SCTE EXPO on the topic of PNM this year.  Topic: DOCSIS Pre-Equalization: Vastly Powerful, Often Undervalued

For those of you who have not heard of PNM, here are the highlights.  DOCSIS Proactive Network Maintenance (PNM) developed by InGeNeOs™ under Cablelabs®.   It is one of the coolest technologies I've been involved with in my 25 years in the industry because it transforms every cable modem into a highly accurate troubleshooting probe.  Some larger MSOs have spent a couple of years developing and optimizing this technology for their systems with amazing results.  The summary being a drastic reduction in maintenance costs and significantly improved operational efficiencies.

The technology is revolutionary in the cable industry and will assist cable operators be more effective identifying impairments in their cable plant FAST and pinpoint the location on a map.  Finding problems quickly with PNM technology will result in lowered maintenance costs for the cable operator and better cable video and high-speed data service for subscribers.  PNM has a little for everyone.  The geek out factor is high so if you are a techie you will love it.  If you are more interested in the financial end of it you will really get excited about the cost savings.  For those of you that are into quality control and customer satisfaction you to are covered with this technology and if you are the tech that has to find the impairment on the hottest or coldest day of the year you too will embrace this technology.  Imagine knowing where to go to find the impairment and have it layout on a map for you.  

Map Modems by Impairments Levels & Distance to Impairments - Nimble-This.com

Map Modems by Impairments Levels & Distance to Impairments - nimble-this.com

Imagine Every DOCSIS Cable Modem is a Test Probe

Through working groups at CableLabs we have learned that by analyzing the pre-equalization data in cable modems we can locate outside plant impairments to within 50 feet or less. This means times savings, customer satisfaction improvements, and increased quality for both the subscriber and the technician.

Cable Modem Coeffeicants

Cable Modem Coeffeicants - nimble-this.com

What does this mean? It means that every cable modem now becomes a troubleshooting device. Let’s take a hypothetical example. A cable modem’s pre-equalization data indicates that there is an impairment on the cable network in addition you can determine that the impairment is located roughly 2491 feet away from the cable modem.  You also know that there is an active 2500 feet away from the modem.  Its pretty easy to put one-and-one together to realize that the source of your problem is at the active and not the subscriber home.  Of course the mapping helps triangulate many modems with impairments when the all overlap on the same point.

Individual Cable Modem Information

Individual Cable Modem Information - nimble-this.com

Since your network maps show that there is an RF amplifier 2500 feet from this particular cable modem, you are able to send a truck directly to the amplifier and find out that there is a corroded center seizure screw causing micro-reflections. You repair the amplifier and see that the cable modem’s pre-equalizer data no longer shows the impairment and its uncorrectable codeword errors are also no longer present. Thus we have dramatically reduced the typical troubleshooting repair time. Most importantly customers are not threatening to leave your service behind.

I will be writing a couple more articles on this technology, explaining how it works and showing some more examples.  If you are interested you can also visit Nimble This LLC and or get a video tour.  Nimble This is the first company to make a commercial product available to all cable operators.  So not only am I working with CableLabs on PNM, I also am working with Nimble This.  One thing I am confident about is that it will change the way we manage our DOCSIS network maintenance for the foreseeable future.

The Volpe Firm is a member of CableLabs DOCSIS Proactive Network Management Initiative and a Contributing Engineer for CableLab’s InGeNeOs(R) initiative.  


Mr. Volpe has over 25 years of communications industry experience. He is focused on the cable and telecom industry with deep technical and business skills. Mr. Volpe is currently the president and chief technologist of the Volpe Firm and holds an MSEE with honors.

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