Market definition: What is included in the NFV market? Software, hardware, virtual functions, and professional/support services can all be considered here.

Use cases: What are the leading NFV use cases (machine-to-machine, CPE, hybrid cloud, etc.) and how will they impact various parts of the existing network infrastructure? How will these use cases drive NFV deployment time frames?

Network equipment in scope: What types of network equipment will be in scope for NFV technology in what time frame? Leading types of equipment under consideration for NFV include the mobile core, IP Multimedia Subsystems (IMS), policy/service assurance, deep packet inspection, WAN optimization, security elements, some routing elements, and many others.

Key benefits: The key benefits that communications service providers will derive from NFV implementation include faster time-to-market, enablement of new services, ability to rapidly scale resources up and down, and lower costs (both CAPEX and OPEX). Which of these key benefits (or combinations thereof) will motivate CSPs to make the significant changes required to migrate to NFV?

Inhibitors: CSPs have large installations of highly reliable, revenue-producing networks. How will NFV impact the existing network? What are the risk factors? Who will provide the expertise to enable NFV migration?

Technological maturity: Some parts of the telecom network (mainly the application and some control plane elements) already run on standard servers (COTS). Other parts of the network (e.g., optical transport, routers, mobile edge, and switches) drive their scale and performance from a combination of proprietary ASICs or network processing units with integrated software -- making them difficult to virtualize. How well will NFV technology scale and how reliable will it be in the various parts (functions) of the network?

Standards/interoperability: The key advantage of NFV is the ability of CSPs to mix and match various software elements on standard COTS hardware. How well will various NFV solutions interoperate? How easily can they be tied to existing OSS/BSS (back office) systems?

Speed: How quickly can CSPs change the relationship between their network and IT operations? In order to broadly implement NFV, large traditional CSPs need to change their current organizational structure. They will have to blend expertise from their IT, cloud, and network organizations. Very few CSPs (and none of the large ones) have this capability today.