ADVA’s ALM monitoring tool gives providers insight into wavelength, dark fiber performance

ADVA's new ALM platform. Image: ADVA

ADVA Optical Networking has introduced a new advanced link monitoring (ALM) platform that will enable service providers to proactively monitor and rectify issues that arise with wavelength services and dark fiber.

The ALM is specifically engineered to be a simple plug-and-play fiber assurance device. It provides continuous in-service monitoring, enabling operators to know immediately if and where issues arise.

Unlike proprietary test equipment, ADVA said the ALM is built on standardized, open management interfaces that can be easily integrated into existing operational support systems. In addition, the ALM product is integrated with major geographic information systems.

The ALM solution consists of three components:

  • Monitoring unit: This device calculates a loss profile of the monitored fiber link by analyzing the reflected measurement signal.
  • WDM Coupler: The test signal operates at a wavelength that’s distinct from the user traffic. A WDM coupler combines both signals on the supervised fiber.
  • Demarcation Reflector: A passive demarcation reflector defines the service hand-off point. However, it does not consume power and can be applied even under harsh environmental conditions.

The ALM can provide continuous in-service monitoring, enabling services to know immediately if and where issues arise. This real-time data can help a service provider supervise and assure dark fiber services, especially when selling higher value service level agreements.

Ulrich Kohn, director of technical marketing for ADVA, said one of the considerations service provider customers asked for was a cost effective monitoring product that could monitor faults from various points in the network.

“The challenge for us was to come up with a cost efficient solution, so we optimized it for short distances, but then customers wanted to be able to address long distances and this was the key element of the product,” Kohn said in an interview with FierceInstaller. “It meets a similar price point, but now the distances go up to 160 kilometers.”

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One of the key features of the ADVA ALM’s engineering is its passive demarcation, which can be configured to passively monitor access services. By eliminating active demarcation, operators can further reduce operating costs and deploy the ADVA ALM in even extreme environmental conditions.

There are a few issues that ADVA said the ALM can overcome.

By using an active demarcation device, a service provider’s ability to scale and extend services could be inhibited. Finding faults on the fiber is also an issue because traditional systems cannot localize fiber breaks and information about fiber links is hidden in higher-layer management system.

Instead, the ADVA ALM uses a passive demarcation and a separate monitoring optical wavelength propagating the same signal along the fiber.

The ALM can also be used to support fiber deployments for CPRI and next-gen front haul services as well as dark fiber services.

“If you have bandwidth services in most cases a service provider would use an active demarcation device to monitor the service at the end of the point, which is tricky to accommodate specific data protocols like CPRI to connect wireless cell sites,” Kohn said. “There is no specialized CPRI demarcation device so we said, ‘you can use a monitoring signal which goes through the same fiber and a demarcation reflector to monitor the fiber up to this well-defined point during a mobile network installation.’”

Interestingly, the emergence of Common Public Radio Interface CPRI and fronthaul services for next-gen cloud-RAN (C-RAN) networks is emerging in tandem with a renaissance in dark fiber. Service providers are offering dark fiber for two reasons: Responding to competition or meeting a regulatory mandate.

On the mobile side, the thirst for dark fiber has been mainly led by Verizon and increasingly other mobile operators. While the dark fiber opportunity initially attracted to insurgent providers like Zayo, some incumbent players like FairPoint and Lumos Networks have started offering it as a service to wireless operators and even school districts.

Zayo, for one, recently won a deal to equip one of its wireless operator customers with dark fiber on 1,800 cell sites. On an even larger scale TPG announced it would equip 3,000 of Vodafone Australia’s cell sites with dark fiber.

Meanwhile, BT has been mandated by the U.K.’s telecom regulator Ofcom to start offering dark fiber to its competitors. In its Business Connectivity Market Review 2016 (PDF), Ofcom has called for BT to give competitors physical access to its fiber optic cables, allowing them to take direct control of the connection.

As more service providers start rolling out dark fiber services, these providers can use the ALM to ensure links are up and running. They can use the ALM to conduct immediate fault notification and real-time root cause analysis if an issue on the fiber occurs.

“Today, dark fiber is becoming mainstream and we have a product that addresses the market to monitor dark fiber,” Kohn said. “We can give the owner of the dark fiber the ability to have real time information on the integrity of the fiber infrastructure and be able to notify a customer if something occurs, which is of great value to dark fiber service providers.”

Since dark fiber is still an emerging service concept, there’s a need for network monitoring. This creates blind spots for the service provider in that they can’t isolate that the outage could be due to a broken patch panel, for example.

“What we frequently hear are scenarios that are using dark fiber, and if you don’t have a monitoring solution, then you don’t have a means to know where the customer problem is,” Kohn said. “A customer could say there’s a problem and the operator conducts measurements and tells the customer they don’t see any problems.”