JOHN WILLIAMSON OPTICAL NETWORKS
OPTICAL NETWORKS: KEEPING THE LIGHTS ON
As ever more human activities are conducted online over optical networks, the detrimental consequences of service disruptions and outages loom much larger. The upshot today is an intensifying industry focus on the development and deployment of tools and methodologies with the potential to minimise downtime and boost optical network resilience and up-time. This is taking place when any prospective threat to resilience, caused by additional complexity, is rising in some network applications, writes John Williamson .
T ake data centres, for remarks Étienne Gagnon, EXFO’s SVP, est and Measurement Division. “Today’s data centres have up 6,912 fibres to be tested and monitored, versus previous 864-fibre cables – a shift because of higher demand and higher speed transmission.” example. “The challenge in data centres is the increasing complexity inherent in high-density cables and fibres being deployed,” What are likely causes of optical network service interruptions or blackouts? Gagnon cites optical connector failures, poor splicing and faulty fibre spans due to poor fusion or macro-bends.
FITNESS TESTS Successful identification of faults and configuration errors at the development and manufacturing stages in the creation of optical devices and systems clearly has the capacity to impact later service performance. “As with manufacturing in many other industries, you will see corners cut so that cheaper equipment can be manufactured, and that cheaper equipment is purchased often on price,” observes Nick Rowan, Global Lead, Fibre Optic Program Marketing at VIAVI Solutions. “Then you start to see the effect in optical networks as lesser quality usually equates to reduced service performance.” Meticulous testing for, and detection of, defects and errors in the installation and turn-up phase of the optical network lifecycle can also be decisive. “Doing installations and turn-ups following an accepted and/or standardised process is critical to ongoing network performance, especially if it is done absent expert installation,” adds Rowan. Not getting installation right the first time equates to greater overall expense as well as expense overtime, whether it’s a cause/effect of problems further in the network, the need to repeat or correct installations, or both. As such, Rowan
judges ‘right the first time’ must be the installation/turn-up mantra.
“Failing to test in the field and simply relying on manufacturer testing is another contributor to outages,” ventures Gagnon. “Rigorous testing at every stage from production, to deployment, to ongoing test and measurement is key to avoid service interruptions.” TOOLS OF THE TRADE Among the tools used in efforts to troubleshoot and minimise network downtime are fibre inspection solutions, OTDRs, power meters, light sources, and spectrum analysers. Also on the menu, according to Gagnon, are: fibre inspection probes that use automated analysis software to gauge connector performance; automated optical loss field testing to identify and characterise problems; and end-to- end testing using centralised OTDR to monitor fibre networks 24/7. EXFO also acknowledges that dedicated single-function test and monitoring devices are giving way to multifunction solutions. “Absolutely. For example, field technicians can inspect single and multi-fibre cables using the same tool
As well as physical damage to fibre cables, Jose Luis Gonzalez, FTTH Network Architect, EMEA at
CommScope, refers to the difficulty in congested handholes of identifying the correct cable, along with wrong product selection when building the network, such as using indoor materials which are not designed for this purpose. “Making sure your planners and production teams are educated in the correct materials for the job is important,” he stresses.
ISSUE 29 | Q2 2022
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