Excentis ensures drop cables don’t limit HFC upgrades
What we learned from analysing 9,600+ cable modems (before pushing more capacity into HFC networks) for a cable operator.
How to validate the future capacity and identify churn risks in the 10G DOCSIS era. Would there be a smarter way to allocate and prioritize the HFC upgrade budget? Many operators execute HFC upgrade investments almost blindly. Teams make decisions without full visibility, only to realize that the infrastructure was worse than expected, forcing them to spend millions more than planned to fix additional problems.
Most discussions around HFC upgrades tend to revolve around adding capacity, more spectrum, more OFDM channels, higher modulation profiles.
But while working through a recent drop cable assessment, a more basic question kept coming back:
Will the existing drop cables actually carry that additional capacity?
We looked at field data from a little over 10,000 cable modems (with ~9,600 usable datasets after filtering) and estimated the achievable capacity per connection, assuming three DOCSIS 3.1 OFDM channels up to 1.2 GHz.
If you want the full details, you can download the use case here
What the data shows
At first glance, the results look reassuring.
Roughly three quarters of the modems can support high modulation on the OFDM channels, and about 92% reach an estimated capacity of at least 4 Gbit/s. So for the majority of the network, adding spectrum should translate into real gains.
But the interesting part is not the majority, it’s the tail.
A small subset of connections performs significantly worse. In some cases, the estimated capacity in the higher frequency bands effectively drops to zero. Those connections won’t benefit from additional spectrum at all, regardless of how much capacity you add upstream.
Digging into the root causes
When you start looking at those poorly performing connections, the issues are not particularly surprising, but they are persistent.
Across the analysis (see the breakdown in the middle of the document), the same patterns keep coming back:
- bad or loose connectors
- water-damaged cables
- long drops or strong frequency roll-off
We also saw impairments like micro-reflections and upstream group delay showing up often enough to matter. Individually these are well-known issues, but seeing them repeatedly across thousands of modems puts them in a different perspective.
Why this becomes a problem during upgrades
On paper, increasing capacity is straightforward. In practice, these weaker connections distort the outcome.
If part of your network cannot use the higher frequencies:
- those customers won’t see any improvement
- performance gains will look inconsistent
- troubleshooting efforts increase after the rollout
So instead of the upgrade simplifying things, it can actually make operational behaviour harder to interpret.
The practical takeaway
What this exercise really highlights is that capacity upgrades and drop quality are tightly linked.
Before pushing more spectrum, it helps to understand:
- how much of your network can actually use it
- where the limiting factors are
- and which issues are worth fixing upfront
That doesn’t require perfect data, but it does require looking at the network from the modem perspective rather than just from the headend.
The full use case goes into more detail on the capacity distribution, root cause analysis, and observed impact.
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#HFC #DOCSIS #NetworkEngineering #Broadband #CableNetworks
