MSO Case Study

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Rev2 Service Providers: MSO Case Study

Rev2 Professional Services recently worked with a leading Multi System Operator (MSO). In addition to correlating the usual network tickets and calls into the call center, Rev2 included data from a sophisticated modem-polling engine.

Using its proprietary tools, the Rev2 team instantly determined that a large number of system-wide cable modems were reporting errors related to a single metric: Microreflections. In fact, this one metric accounted for nearly 45% of all CM events.

Microreflections generally indicate an impedance mismatch. So seeing them systemically occurring suggested that there likely was a significant issue with terminations. Interestingly, the Rev2 team found many correlations between these issues and subscriber complaints.

The team correlated subscriber calls at the node:street level with Microreflection issues and found that chronic failures that were affecting subscriber. This wasn’t just a theory – it was actually affecting performance. This wouldn’t have mattered much if the MSO were running QPSK (Quadrature Phase Shift Keying), which would allow the system to carry twice as much data. But with 16 or 64 QAM (as was the case here) the effect was substantial.

Too Many Targets

Once the issue was identified, the only problem was that there were potentially too many targets to go after. A deeper analysis showed that few microreflection events were near the threshold of 45 dBc. A normal distribution of failures would have put most errors close to 45 dBc and then tapered down. Rev2 identified the expected curve, but with a massive spike up between 86 and 100 dBc.

In fact, 80% of the microreflection events were in this range. Why the discontinuity?

The Rev2 team had a theory – adaptive pre-equalization. Starting with DOCSIS 1.1, the modems can actually compensate for termination issues… to a point. It seems as if the modems are doing their job by managing termination issues, up to 86 dBc. If this is true, the noise at 86 dBc overwhelms their ability and the spike emerges.

Therefore, Rev2 recommended modem upgrades as a potential solution. Rev2 suggested that DOCSIS 2.0 and later would have a greater ability to compensate. The modem upgrades would improve performance and drive down associated costs (such as subscriber calls).

To arrange your Proof of Concept, please contact us at infoatrev2dotcomdot  (infoatrev2dotcom)