You probably know that Proactive Network Maintenance (PNM) is about finding and fixing problems before they impact the customer. But the other side of PNM is about managing the capacity or bandwidth available in the network. PNM may have started with the former concept in mind, but the latter is becoming more important as we rely on higher amounts of capacity at the edge. As the world adjusts to life under the COVID-19 pandemic, access network capacity is becoming even more critical. PNM is an important tool set for network capacity management, and CableLabs is helping operators manage network quality and capacity together.
Network condition impacts network capacity. Network impairments, a broad class of failures and flaws in the ability of a network to carry data, have to be addressed before they lead to service failure. The DOCSIS® protocol is a method for sending data over multiple radio frequencies in hybrid fiber coax networks, and comes with several resiliency mechanisms that help service continue in spite of impairments, to a point. These impairments in the cable plant may impact a few or all frequencies. Impairments that impact specific frequencies may or may not be able to be compensated for, on those frequencies. If severe, the impairment may impact the data carried on those frequencies entirely, leading to correctable or even uncorrectable data errors. If not severe, profiles may be able to adjust to lower modulation orders to allow less data to be reliably carried than otherwise. Impairments that impact a larger amount of frequencies of course have a greater impact on the bandwidth the network can carry. In any case, impairments impact the capacity that the operator can get from the access network.
This is why PNM, which is an important set of tools for network operators to manage network condition, becomes even more important as we depend more on our network capacity and move toward higher utilization of the access network capacity. As demand for bandwidth increases at the edge, PNM becomes an important network capacity management tool for network providers. The difference between a perfect network and one with flaws felt by customers begins to shrink. PNM begins to be imperative; it is “table stakes” for maintaining communications services and managing the capacity of the network.
CableLabs has been working with these issues in mind for some time. In July of 2019, I wrote on the subject of 10G and reliability, pointing out that higher bandwidth solutions closer to the customer will be required for 10G. Then, in August, I wrote on the subject of reliability from a cable perspective and pointed out that the impairments addressed through PNM impact capacity. So, we see that reliability and network capacity are closely coupled. As we move toward higher bandwidth services, expand the utilization of frequencies and further push the limits of technology, reliable and sufficient bandwidth become highly coupled. Therefore, so do the tools that network providers use to manage these service qualities. CableLabs is working on solutions to help operators succeed in this reality.
Recently, CableLabs announced the release of a new capability in our Proactive Operations (ProOps) platform that uses RxMER per subcarrier and profile information to inform the selection of PNM opportunities. Also, our PNM working group announced the release of our DOCSIS 3.1 PNM primer of engineering practices, which we intend to develop toward best practices for the industry. If you are an operator or vendor interested in this subject, contact us for more information and to help us develop this solution for the industry.
 Because of the resiliency of DOCSIS® technology, impairments in the network have an impact on the capacity available in the network for serving customers, even when service remains functional, and even when customers may not notice right away or always. Without resiliency, an impairment leads to failure. Network resiliency is what keeps service running over impairments, which lets operators fix problems before they become severe and provide highly reliable services.
Originally published at https://www.cablelabs.com on June 29, 2020.