One problem I have come across lately is the fact that one of the tenet of NFV and SDN is to reduce potential of vendor lock-in at the hardware level. It is true that virtualization of the software allows commercial off the shelf servers to be used in lieu of appliances, for a fraction of the cost of acquisition and operation.
One of the problem that is emerging is the testing, monitoring, troubleshooting and quality assurance of virtualized networks. Vendors in this field have traditionally relied on passive probes performing traffic interception and analysis at various point of the network / interfaces.
In a SDN/NFV world, it becomes difficult to test / monitor / troubleshoot a single service when the resources associated with the service are mutualized, virtualized and elastic.
Right, now most virtualized functions are at the service / product level, i.e. a vendor takes a product, for instance EPC and virtualizes it and its components. The deployment remains monolithic and while there might be elasticity within the solution, the components themselves cannot be substituted. This result in a multi-vendor environment only as far as the large functions are concerned, but not at the component level.
Monitoring and assuring traffic between components become problematic because of the lack of standardization of East-West interfaces.
Testing, monitoring, QA vendor must virtualize their offering through virtualized software probes and taps implemented as virtual network interface cards (vNICs) or switches, but more importantly must deeply integrate with orchestrators, element managers and controllers in order to be able to monitor the creation, instantiation and growth of virtual machines.
This implementation requires the maintenance of a stateful mapping of network functions and traffic flow in order to correlate data and signalling planes.
At this stage, vendors in this field must prepare themselves for a rather long business development engagement in order to penetrate the ecosystem and integrate with each vendor / solution independently. The effort is not unlike one of orchestrators who need to integrate deeply with each network virtual function vendor in order to accurately understand their respective capabilities and to build the VNF catalogue and lifecycle.
As for many in the NFV space, the commercial strategy must evolve as well towards licensing rather than transaction / volume charging. Virtualized network functions will see the number of elements and vendors grow to 100's and 1000's and inevitably, large system integrators will become key single interface to network operators.