DOCSIS PNM Shapes the Assurance Strategy

It has been more than a decade since CableLabs began defining and promoting Proactive Network Maintenance for DOCSIS. Even so, the adoption and everyday use by cable service providers is still very much a work in progress. It is taking time to integrate the methods and lessons learned into the service assurance systems and platforms to drive the daily operations for cable providers.

What do we really know about fraud in DOCSIS networks? Read on to find out 5 Quick Tips about Fraud in DOCSIS Networks.

Still, there are some key concepts from the DOCSIS PNM work that has had a significant influence on how the cable service providers think about service assurance. Those concepts are:

  • Making use of data from the actual network devices that are providing the service.
  • Defining the requirements of equipment vendors to support measurement and data collection from each of the network elements.
  • Explanation of the concepts and providing industry standard best practices for the data analysis
  • Promoting a culture of proactive (vs. reactive) ways of viewing network health and performance.

Early in the development, the DOCSIS PNM work centered around taking advantage of the data that was already available. The group realized that the pre-equalization tap values were a valuable source of information about the health and performance of the HFC hidden within the cable modem operations. With pre-equalization enabled, the CMTS makes calculations to account for the frequency response of the upstream. The DOCSIS PNM team developed the math to use the equalizer tap values to provide a clear and measurable characterization of the modem return path. This concept makes every modem a “test point” and uses the real signals to characterize the behavior of the network.

Once the network devices become the “test points,” there is a clear need to make sure the PNM platforms have access to the data within the network device. The DOCSIS PNM group went on to define requirements of the equipment (modems, CMTS, nodes) for what types of measurements they should take and what data should be made available to PNM systems for analysis. They submitted the concepts and requirements to be included in the DOCSIS 3.1 PHY specifications.  This standardizes the types of data to be used in the network analysis and allows the PNM systems to focus on what to do with the data.

The industry experts didn’t stop there. They went on to clearly define the ways to use this data and published a best practice document that details the measurement and analysis methods. By working closely with the SCTE, the aim is also to provide training materials to go with the PNM best practice guide.

This approach has redefined the cable operator’s expectations around service assurance tools, and workflows. With an effective PNM platform and program, anyone in an operational role that touches service assurance (from the installation technician to NOC persons, through the support tiers, and the engineering groups) now expects access to meaningful, data-backed insights into the overall health of the network.

You can tell a lot about the nature of the HFC network from how the devices providing the services. It is no wonder that these concepts are quickly finding their way into video service monitoring, wifi, transport, and the network core.  As demonstrated through the DOCSIS PNM work, these concepts can provide significant insight into the network performance and health status.

As we move forward, there will be a definite advantage for service providers that invest in Proactive Network Maintenance tools and platforms. It will no longer be good enough just to know when a service is working or not working. Correct service assurance methods will take constant monitoring of the service delivery, and integration of that knowledge into the service provider policies and workflows.

What do we really know about fraud in DOCSIS networks? Read on to find out 5 Quick Tips about Fraud in DOCSIS Networks.

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