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uncertainty lies between the present situation and that future. The problem is this: can we trust a network based on NFV? Logically we should be able to, provided the functions are properly virtualized. But complex systems don’t always reflect simple logic, and surprising behaviour can emerge in a complex network. A virtual network must be aware of the constraints imposed by the underlying physical topology. In practice, a security system that re-routed signals to a central controller for packet inspection could add latencies that lead to unexpected consequences. A DoS attack, or simple “domino effect”, could crash the system internally. Of course, the only sure solution to such uncertainties is stringent testing under realistic operating conditions. In the case of a fast-evolving virtual system this also includes on-going monitoring as the system reconfigures to make sure that the new configuration has not introduced a problem. After all, a ‘virtualized network’ function is still a network function. It can be Network Virtualisation tested as such in much the same way as it’s physical equivalent. However, physical test ports are now no longer sufficient. Testing needs to come from within the virtual infrastructure and should also seamlessly span the virtual and physical realms. Performance, availability, security and scale of any proposed solution must be assessed as before particularly given the potential of the new networking paradigms to affect these aspects both positively and negatively. The good news is that the network test industry is ahead of the virtualization game – test and monitoring devices have themselves been virtualized and, in this form.they can adapt as rapidly as the systems they are testing. Using the latest test techniques correctly, you can be as well assured of the performance of virtual systems as of any physical set up. But is that all there is to it? Not quite, because every major new development requires new learning. We have the tools for testing virtual systems, but the swamp of uncertainty still lies between now and the golden future of NFV and SDN. The only way to tackle such uncertainty is to call on the wisdom of acquired experience. When new challenges arise, even though they really are new they can still be analysed in terms of what has already happened before. The network test industry has many years experience of not only testing networks but also adapting to constant changes in the technology and the business environment. We can be pretty sure that NFV will throw up some surprises, and maybe need drastic remedies. But we can also be sure that test teams with sufficient experience and skills will find a way around these problems and learn to anticipate them – as they have always done in the past. The moral of this tale? Get on the NFV bandwagon, grab the opportunities and competitive advantages it promises — but make sure you do it in the company of truly experienced network test specialists! www.microwave-eetimes.com Microwave Engineering Europe March-April 2014 15


MWEE MARAPR 2014
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