These days Network Functions Virtualization (NFV) and Software Defined Networking (SDN) have become the buzzwords. Organizations are feverishly working out their strategy to define how their solutions fit into that space. In the process the basic definition is being adapted to suit individual needs. Let’s try and understand what NFV is, what factors are driving it, why we see it as something real, and above all how it fits into the overall canvas of network orchestration.
Network Functions Virtualization as defined by ETSI is an implementation of network functions in software that can run on a range of industry standard server hardware, and that can be moved to, or instantiated in, various locations in the network as required, without the need for installation of new equipment.
That brings us to the question what functions can be virtualized? It can be anything, but the choice will be primarily driven by whether implementing the function on commodity hardware meet the need of the service, especially performance. The benefits of being able to virtualize a network function on commodity hardware are many, starting from lower cost, faster time to market, using software driven orchestration to deploy services quickly, thus addressing the network operators’ ability to scale up and scale down on demand (Elastic Services). Essentially, with NFV, we see an adoption of scale out model where many individual appliances are deployed geographically to meet the requirements of scale rather than big and dedicated network equipment.
NFV is applicable to Wireline and Wireless Network Products and, in fact, we see that it spans across domains. For us the NFV story is spun around the two main tenants, virtualization of our control plane solutions in the mobile, convergence and data communication networks and ability to repackage our data plane software. The combination can be very effectively hosted on commercial hardware to meet the demanding need of the appliances. This enables an end user e.g. OEMs to deliver production grade solutions very quickly and efficiently as they can define the value added service by organizing the orchestration of an application or a combination of applications (Service Chaining).
Control plane solutions have been deployed very effectively on general purpose servers or server blades on an ATCA platform. The very same functionalities such as Routers, Mobile Packet Core, and Session Border Controller can be now easily deployed in the form of Virtual Appliances (combination of Control Plane and Data Plane). The appliances can be orchestrated on high volume servers and storage and interconnected by an Ethernet Switching Fabric.
The last couple of years have seen significant advancement in virtualization technology. The Multi Core Multi Socket compute servers can be very effectively virtualized. Multiple technologies (Middleware / Network Operating System) are available to facilitate efficient communication among these virtual environments while ensuring the necessary isolation. The network I/O virtualization has further given a fillip to that process. The network accelerators which are integrated with server devices are capable of offloading many network functions very effectively leaving enough horse power for the appliances. The virtualization technology enables the sharing of the resources giving rise to the concept of multi-tenancy, which makes the solution more effective.
With an effective technology in place it is only natural that more and more applications are virtualized to reap the benefits it offers. We see NFV as an extension of that. Network Appliances like Deep Packet Inspection, Firewall can now be hosted as tenants on Compute Servers very efficiently.
That brings us to our next leading question on SDN, which has taken the networking community by a storm in the last two years. SDN can be viewed as creating and abstracting networks that can be manipulated by a controlling application. The controlling application may reside in virtual environment (tenant). We think SDN and NFV are distinctly different. The overlap is when SDN creates an environment i.e. abstraction of the network. Here the network elements can be dedicated hardware or has been realized through functions/applications that have been virtualized (NFV).
Today, the concept of innovative applications controlling a network is gaining traction. OpenFlow, which has been synonymously used with SDN, is an effort to develop a standard interface to control a category of network elements from the controller. Again we see that the OpenFlow Data Plane can be instantiated on a server processor very effectively realizing a forwarding appliance, which is very similar to any other hardware-based forwarding gear. An example of realizing a complete solution can be Aricent Data Plane Software used to build forwarding appliances. Aricent Control plane is used to build a Tenant Application. The end user / OEM build the complete SDN picture using their orchestration logic to provide a meaningful service.
We see NFV as something that would roll into the networks early given, that proven framework exists for cloud orchestration, and which can be extended to orchestrate appliances in Carrier Networks. The rational for using Industry Standard High Volume servers is to drive down cost, and the existing frameworks providing the necessary infrastructure to deploy services quickly will only speed its deployment. SDN will take off on top of it. However, in the environment where NFV has not taken off (for example orchestration of Optical Networks) pure SDN will be there to start with. Effort to build in concept of virtualization in its own way is also on for those networks.
Is NFV a cake walk? No. Significant challenges have to be overcome before NFV becomes a reality. The issues are the same that all new technology solutions face; co-existence with legacy systems, interoperability, maintainability, security, reliability, and resilience. Given the benefits it offers, we would like to see a quick uptake. With Network Operators rooting for it, we can only say it is here to stay.