---Simple understanding of SDN and NFV

SDN has received extensive attention in academia since 2012. After reading some of the relevant summary articles written by some foreign Daniel, it seems that the shadow of NFV is not seen.

When it comes to SDN, the three features that can be thought of are basically "control-and-forward separation, programmable interfaces, and centralized control." Although these three specific is very important, it is also the value of SDN existence. But in addition to this, there is the NFV, which is the network function virtualization, that accompanies the development of Sdn.

1. SDN comes from Stanford Labs, and it's academic. And NFV comes from industry.

2. SDN and NFV can exist independently of each other, and according to relevant studies, the results are more effective, but there are more problems to be addressed.

3. On the big side, SDN and NFV propose the concept of separating software from hardware. But after refinement:

SDN focuses on separating the control modules at the device level, simplifying the underlying device, and centralizing control, and the underlying device is only responsible for data forwarding. The aim is to reduce the complexity of network management, the cost and flexibility of protocol deployment, and network innovation.

In the case of NFV, the function of the device is extracted, and the virtual function module is provided in the upper layer through the virtualization technology. That is, NFV wants to be able to use a common x86 architecture machine to replace the underlying heterogeneous specialized devices, and then, through virtualization technology, provide different capabilities at the virtual layer, allowing functionality to be combined and detached.

4. Virtualization technology is also present in SDN, but it is fundamentally different from NFV. SDN Virtual is a device, and NFV is a virtual feature, and of course NFV also includes the virtual, or NFVI, of the underlying device.

ETSI has now completed its first phase of NFV work in 2015-1, including the architecture of NFV, the interface between tiers, and management.

and plan to implement the second phase of NFV in the next two years, as described in the white Paper by ETSI ISG, the second phase will focus primarily on addressing interoperability issues in NFV (which should be between VNF and the communication and collaboration with VMS).

---Simple understanding of SDN and NFV