XXXX XXXX JOHN WILLIAMSON OPTICAL VIRTUALISATION
VIRTUALISATION CHANGES THE FACE OF OPTICAL NETWORKS
With the need for greater service agility, planning, configuration, re- configuration, customisation and scalability set against a background of financial constraints, it’s no wonder interest is building in the virtualisation of fibre-optic transport networks. John Williamson looks at the latest developments.
“Managing end-to-end optical services in this environment has been a service provider pain point.” THE VIRTUALISATION COOKBOOK There are a number of different strands to the virtualisation proposition for optical networks. Software Defined Networking (SDN) has a different focus to Network Function Virtualisation (NFV). “In optical networks, SDN is about controlling and managing the optical network and services, including virtualised optical services,” points out Larrigan. “NFV provides the platform to scale these SDN functions and support network optimisation functions. The two technologies complement each other and will continue to do so in the future.” This suggests different impacts in different parts of the network.” Optical networks are about transporting the service, whereas access/edge network functions have more of an implementing-the-service component,” continues Larrigan. “Hence, the access/edge will likely leverage NFV to implement service components. Optical networks will use virtualisation to scale end-to-end transport functions, including network optimisation functions.” the concepts of disaggregation and network slicing. According to Helen Xenos, Ciena senior director, Portfolio Marketing, one contemporary trend in optical networking is a move towards disaggregation of software from the network element, and moving those functions to a centralised SDN controller. “By disaggregating software control to a centralised controller, and implementing the same standardised open APIs on multi-vendor network DISAGGREGATION: NEW HORIZONS Virtualisation is closely linked to
I n January 2018 Vodafone Ireland and Huawei reported the trial of a virtually partitioned physical FTTH network. In the same month NXP Semiconductors announced that its vCPE solution had been put through its paces in a China Mobile Communications Corporation demo. Also in January, Telefónica and Huawei said they completed laboratory tests on the latter’s Transport Software- Defined Network (T-SDN) system. As is evidenced by these and numerous other similar developments, interest in the further virtualisation of networks is rapidly building a head of steam. It’s not difficult to appreciate why. At the big picture network level, virtualisation has the potential to: reduce operating expenses (OpEx) and capital expenditures (CapEx); streamline service agility; take planning, configuration, re-configuration, customisation and scalability capabilities to new levels; and dramatically shorten times for the provision of new capacity and services. As such it is hailed as a powerful antidote to some of the shortcomings of current optical networks.
constraints. As an example, Vikash Rungta, Infinera senior product manager, instances conventional transponder- based WDM networks, in which each service is directly coupled to a specific wavelength, and service activation speed is limited by analogue optical engineering and deployment of all the equipment necessary to ensure its successful end-to-end transmission. A new service therefore requires a new wavelength deployment, which in turn requires the management of many complexities. “Ideally, network operators should be able to deploy additional capacity and support new service types quickly and easily, with a minimum of manual intervention, hardware deployment, and engineering complexity,” suggests Rungta. “In such a case, service deployment would be more of a matter of software-enabled network reconfiguration, thereby ushering in the concept of a “programmable” optical network.” Again, interoperability is an issue with optical transport solutions from different vendors. “Interoperability is something that has traditionally been avoided by deploying different optical vendors in separate network domains and/or geographies,” observes Scott Larrigan, senior marketing manager, Nokia.
CURRENT CONSTRAINTS Present day optical networks have a number of design and operating
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| ISSUE 14 | Q3 2018
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