MATTHEW PEACH BIDIRECTIONAL TESTING
meet required bandwidth, availability and reliability requirements.” Modern Optical Loss Test Set (OLTS) systems, such as AFL’s Rogue OLTS, automates much of this process by configuring one OLTS as the master communicating to a slave OLTS over the fibre-under-test. When automated testing is completed, the OLTS automatically computes and displays results in each direction as well as average loss. MODERN AND LEGACY MIX Looking across the networks already deployed today, which can comprise the latest technologies with a mixture of legacy hardware, and innovations such as 5G and metro splicing, it is clear that these different elements are increasingly overlaying each other. This creates extra levels of complexity so operators need to be able to support and test legacy services while being ready to move with the modern technologies. “To me this is a core challenge,” says Exfo’s portfolio marketing leader Olivier Tremblay-Lavoie. “Network operators need to be able to move towards next- gen solutions while continuing to support existing systems and client services. This impacts on testing both during and after extensions and upgrades and places extra pressure on the operators.” Viavi too is making significant developments in its testing portfolio to support the testing of new network technologies, as Charlene Roux explains, “Our Fibre Optics business unit looks at the physical layer but we also have a wireless unit, and from 4G we are moving towards 5G testing. Viavi was one of the first companies to launch a true 5G RF analyser for the RAL networks. We also have a Transport Business unit for Ethernet layer testing. Our Fibre Characterisation Kit is more advanced, as it can also do OTDR testing but also chromatic dispersion, switching by one button. We also offer a combination of this with a Multi Push On switch to test 12 fibres in a sequence such as for ribbon fibre testing.” For example, Viavi’s OSCA 710 is the first in-service Pol-Mux Optical Spectrum & Correlation Analyser – essentially a spectrum analyser module enabling OSNR signal measurements for POC-multiplexed signals. This is the first instrument to use a novel spectral correlation technique (SCorM, which has a Viavi patent) to enable the measurement of in-band OSNR, and per channel chromatic dispersion at up to 400 Gbps, without shutting down the network or individual channels. IXIA’S MARKET VIEW Charles Seifert, senior manager, product management, at Ixia, tells Optical Connections, “Many operators in the optical transport network business buy the Ixia testers so that they can perform bidirectional, end-to-end testing. But now
AFL Flexscan in use
Exfo last year launched Astelia at Mobile World Congress, with a portfolio of active testing solutions. Gold continued, “The capability of Astelia means that we can see much deeper into how the customer operates. Previous to that we had acquired a company called Ontology for virtual networking. Ontology keeps track of all the different services in order to identify when there is a fault in the network.” Gold adds, “There’s so much change in the network sector and the bidirectional testing marketplace at the moment, associated with disaggregation. It will be interesting to see what a lot of large-scale equipment vendors will do in reaction. They may feel that they will be better off going towards common standards and vendors. I don’t see any of the major test vendors buying into the other big vendors. But I think there are opportunities for micro-acquisitions.” So, has this recent significant change in the test marketplace led companies such as Keysight and Ixia to change their approach or evolve your design of test systems? Andy Moorwood answers, “Yes and I guess that the fundamental difference is that rather than a device/unit under test in a software quality lab, there is a trend towards testing as part of a service provider’s network. We have had a number of developments over the years where we have put different versions of our products, virtualised so that they can be put in the Cloud, and tested in the Cloud. This is something that has only been at Ixia for the past 18 months.” He concludes, “We are technology- agnostic so we can talk about both hardware and services testing. And we are already working with some network equipment developers and manufacturers to embed testing systems.” CONSOLIDATION AND DEVELOPMENT
the big explosion of optics is not really on the optical transport network, it’s on the client side. So 400G-E, the PAM4 encoding, and 56G in signalling is where all the action is for applications such as data centres, for NEMs (Network Element Management System), for people building silicon communications devices.” He adds, “For example, we would be on the access and client side service, transmitting traffic into edge routers, which are also used data centers. So we can test the connections between different buildings in a campus and connections between campuses at up to 40km, which will soon be 80km. There’s even a movement now to stretch to 120km.” Viavi is also seeing diversification and growth in its target optical markets; Charlene Roux adds: “What we are seeing now are the deployments of fibre for FTTH, for data centre interconnects and for new backhaul systems. Now we are seeing more and more fibres going into these applications, more than one, sometimes multi-ribbon cables. But another challenge is increasingly that that the technicians can be less savvy so they are looking for easier tools that provide the test info and the analysis pretty much automatically and that can get the results out easily for the service providers, to Cloud-based solutions or into data management systems.” bidirectional testing sector is now too complicated for individual operators to have a personal overview. “The whole network is changing. 5G is more than just a new radio system, it’s a whole new way of running a network. If 4G was made for people then 5G is made for machines. We are seeing network slicing, automation and zero-touch operations, so these functions, including testing, will not be managed directly by people,” he says. TEST MARKET Exfo’s Ken Gold agrees that the
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| ISSUE 18 | Q3 2019
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