Paper examines how PoE, converged applications stress twisted-pair cable

Document lays out what it takes for cables to support IP voice, video and data as well as the heat and noise implications of Power over Ethernet.

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A white paper available from Berk-Tek provides detail on the results of testing conducted at the Nexans Data Communications Competence Center (DCCC) to quantify the extent to which twisted-pair cabling systems can support the applications that commonly run over them. The paper also describes the impact of Power over Ethernet on these cables. Berk-Tek is a Nexans company, and the DCCC is located in the same facility as Berk-Tek’s headquarters in New Holland, PA.

The document’s introduction explains, “Transmitting ‘data’ has transitioned from transferring simple text files to now include large, graphically intense documents and files, as well as transmitting data packets in the form of Voice over IP (VoIP) and streaming video such as for IP cameras … The DCCC has developed a new test that closely replicates the challenges faced by current and future converging networks. The test results provide insight into how cables will perform when faced with the challenges of simultaneous transmission of voice, data and power in stressed environments.”

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The paper emphasizes that the tests carried out at the DCCC included frame error rate (FER) tests rather than bit error rate (BER) tests, explaining that FER testing “provides the ratio of the number of incorrect frames to the total number of frames sent. Since frames are the basic unit in real-world networks, they are a better indicator of network performance.” In addition to FER testing for data, the DCCC conducted Mean Opinion Score (MOS) testing to emulate VoIP quality and Media Loss Rate (MLR) testing to emulate IPTV and video quality. A graphic depiction of the test setup included in the paper is shown above.

In short, the testing found that a minority of the cables passed the gamut of tests, and most failed. The final couple pages of the document describe the physical characteristics of a twisted-pair cable that enable it to perform well in these stressed environments. It pays particular attention to Berk-Tek’s own cables as well as their design and manufacturing processes.

The paper is available for free download to individuals who provide their contact information. You can download the paper here.

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