By Prayson Pate

The hot topics of Software-Defined Networking (SDN) and Network Functions Virtualization (NFV) have spurred several articles comparing and contrasting them. This blog provides a brief survey of these articles in chronological order, including a synopsis of each. I also included a rating of each, based on relevance and readability.

Uniting SDN and NFV- 4 stars

Tom Nolle of CIMI writing at CIMI’s public blog – November 13, 2013 – 927 words
This blog is one of the earliest to tackle the intersection of SDN and NFV. It focuses on the announcement of the 6WINDGate product from 6WIND. Tom describes how this type of product and approach could unite the two concepts:

This capability is useful in three ways; first, you can use it to improve how servers manage things like virtual networks, and second you can use it to host network-related applications like firewall, NAT, DHCP, and even IMS components. Second, you could use it to create a network appliance, as some appliance vendors already do using 6WIND software. The best thing is that when you visualize network functionality as a hardware overlay usable either by servers or embedded-control-based appliances, you can decide where to host things—network or server—based on all the possible technical and business considerations. If operators really want to drive NFV to the ultimate hosting of all non-packet-forwarding functionality on servers, that’s fine. If they want some tightly coupled things hosted on appliances optimized and located for maximum performance, that’s fine too. In theory, a “service cloud” could be created from the software with network devices and servers both playing their optimized role, and with a common orchestration process putting it all together. That’s compatible with the vision that the NFV operators show in their white paper, but it’s also at the minimum a better way of migrating from current discrete-device networks to a more server-hosted model.

NFV and SDN: What’s the Difference? – 5 stars

Prayson Pate of Overture writing at SDNCentral – March 30, 2013 – 992 Words
I wrote this guest blog because our team and our customers kept asking “what’s the difference between SDN and NFV?” This article provides a brief definition of each based on the controlling documents, and provides an example showing how they can be used in conjunction. It also includes a table comparing SDN and NFV, which was later converted into the infographic below. As of this writing, it is still the most popular guest blog at SDNCentral.

SDN & NFV: Where’s the Synergy? - 3 stars

Sam Masud writing at Transformed Datacenter – May 31, 2013 – 561 words
This blog explores some of the characteristics of SDN and NFV with quotes from some industry experts. One of the interesting points in this article is the lack of consensus on Northbound APIs for network controllers.

According to Rob Sherwood, principal architect at Big Switch Networks, quoted in SearchSDN, “Without a northbound API, all network applications must come directly from equipment vendors [or from their partners], which makes it more difficult to innovate in your network.” In fact, there are said to be about 20 different SDN controllers supporting different APIs. Some also make the argument that a standardized northbound API is not really necessary.

NFV vs. SDN: How Will They Affect the Industry? – 5 stars

Yaakov Stein of RAD writing at RAD.com – May 2013 – 532 words
In this article Yaakov provides some background on the problems that spurred NFV and SDN. He then goes on to define each and give some of potential benefits of each. Yaakov always likes to be a bit provocative, and this article is no different. Its summary provides an interesting estimation of the long-term impact:

If NFV completely captures the market, equipment vendors will essentially become specialized software development houses. If SDN completely replaces conventional networking protocols, the very differentiation between computation and communication will disappear, and with it the networking industry as we know it.

Understanding the relationship between SDN and NFV – 4 stars

Tom Nolle of CIMI writing at SearchSDN – June 2013 -1075 words
Tom provides some of the historical drivers for SDN and NFV, along with an overview of three different models for SDN. He provides some interesting thoughts on the intersection of SDN and NFV, along with the impact of cloud / datacenter principles for implementing each. Tom also provides some thoughts on expanding beyond the datacenter:

NFV’s use of virtual network overlays could also drive an expansion of this SDN model beyond the data center where it’s focused most often today. If NFV allows services to be composed of virtual functions hosted in different data centers, that would require virtual networks to stretch across data centers and become end-to-end. An end-to-end virtual network would be far more interesting to enterprises than one limited to the data center.

In mobile networks, SDN and NFV mean service orchestration – 3 stars

Indranil Chatterjee of OpenWave Mobility writing at SearchSDN – June 2013 – 940 words
Indranil relates some of the issues currently faced in mobile networks, and describes how SDN and NFV could be used to build solutions. He describes an interesting application related to simplified application development:

The second challenge that could be addressed by SDN and NFV is a concept that is interestingly not talked about as much in the context of SDN — separation of application logic and enforcement from corresponding subscriber data. In many applications today, such as the policy and charging rules function (PCRF) and home subscriber service (HSS), the subscriber data and application logic/enforcement are banded together, usually in a proprietary interface, resulting in subscriber data that resides in multiple silos leading to data duplication, storage inefficiencies, data errors, complexity in the application related to HA and ultimately increasing the complexity and time to market for new applications.

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