Whenever a new technology evolves, many buzz words try to define and describe their true meaning and purpose. Software Defined Networking (SDN) and Network Function Virtualization (NFV) are technologies which went through such commotion of finding their true meaning and purpose in the networking industry. In the past couple of years, vested vendor strategies dominated causing market segmentation esp. in SDN Controllers. Year 2014, seems to have begun with some vendor consolidation and we hope that this trend will continue for the next couple of years until Open Standards evolve and compliance issues are resolved.
In contrast, technologies like cloud computing and server virtualization have surpassed the hype cycle to become mainstream technologies and have already revolutionized the IT world. Thus, what server virtualization and hypervisor technologies have done to IT could be done by NFV to Telco network by virtualizing every network function (like IMS Core, Mobile Core, Load Balancers, etc.), thus leveraging the scale of IT while avoiding vendor lock-in and barriers entry due to hardware.
Putting together these complimentary technologies (SDN and NFV), Telcos can save unprecedented costs while achieving scale of IT, service innovation, automation and orchestration as well as simplifying their networks and OSS/BSS infrastructures. This will help avoid all the clutter caused due to multi-vendor, multi-layer and multi-technology network infrastructure that is deployed in their current networks. Therefore, there is an increased interest in SDN/NFV, and Telcos are driving TEMs, ISVs and SIs faster towards this goal than predicted. This post will define such ‘Buzz words’ which are often used out of context, in turn, hindering the true role of SDN and NFV technologies, which are primarily meant to give a fresh perspective to Networking and leverage the scale of IT.
Software Defined Networking is an interlocking group of control plane and data plane technologies exposing Standards based north bound (NB) and south bound (SB) interfaces that can be leveraged by intelligent (Analytics) applications to control their network hardware. If one were to define SDN architecturally, it constitutes set protocols and technologies that work to provide centralized and global network for intelligence-based application control, avoiding all the rigid traditional design practices which lead to locally optimized but globally confused paradigm of Traffic Engineering and open up the network for seamless Application Control in Standards driven Open Networking Environment (ONE).
These guiding principles avoid vendor lock-in and break the barriers to entry, making the standards based networking hardware, cheap and dumb, but diverting attention of hardware vendors to focus on features like performance and security. This will also enable them to think of offloading certain network functions to Switching Silicon and help free the compute & storage resources in the context of NFVI. Though the hardware can still be differentiated by vendors, for Telcos it will make the network infrastructure more homogeneous through standards based NB & SB interfaces. Such applications use a network controller as a gateway to access the APIs on the devices. The most popular gateway is OpenDaylight which is being built through a consortium of TEMs, is widely available; the API standards of which are being driven by the ONF. Thus, in principle SDN provides for reduced CapEx and OpEx while delivering Agility and Flexibility for Applications to Innovate on ONE.
Network Function Virtualization is a complimentary technology to SDN, which aims to transform the carrier networks which are traditionally built with a legacy & fragmented vendor equipments. It promises to evolve and consolidate most of these equipments as network functions on standard IT virtualization technology running on industry standard high volume servers, switches and storage. Specifically, it involves implementing these network functions using software that can run on a range of commodity industry standard server hardware which can be moved to, or instantiated in, at various geo locations in the network as required programmatically, without having to install new equipment. This enables significant reduction in CapEx, OpEx, Space and Power Consumption while providing scale of IT for Telcos. By integrating NFV with SDN, one can enhance performance, simplify deployments, and facilitate operations and maintenance procedures.
Many vendors have already built integrated NFV and SDN Controller platforms (NFVI) viz. ALU CloudBand, Juniper Contrail and HP OpenNFV to name a few. But NFVI can also be built leveraging vanilla versions of OpenStack and other OpenSource Controller platforms like ODL which provide ready plug-ins for an integrated solution. Further sensible applications can be developed for network operations which automate VM management, application lifecycle management, smart placement, and network configuration. It is also possible for the OSS applications to automate, orchestrate and service chain different VNFs and innovate on new service offerings.
Having outlined the true meaning & purpose behind SDN and NFV technologies, two important phrases still remain to be briefly clarified, namely, Automation and Orchestration which are often confusingly used to hijack the purpose behind SDN/NFV. At times, SDN technology was more looked upon as a way to automate the network provisioning which already existed in the industry through many scripting languages leveraging equipment interfaces like CLI, SNMP, TL-1, Web Services, etc. and Orchestration was looked as a mechanism to leverage automated scripts to provide network services through the use of self service portals and applications (offline/static OSS).
But today, the role of Automation and Orchestration in SDN/NFV context goes beyond just scripting and offline OSS based provisioning. They are inherent part of SDN Control System where applications constantly collect network intelligence and take dynamic decisions to ensure service assurance to provide a more real-time OSS. Their functions go beyond the traditional operational and maintenance procedures. As an example, orchestration in the context of a business application can take request from a customer via a web portal for new virtual server requiring provisions and can analyse the network configuration and implement the configuration change for the customer and then update the billing system. The network itself might implement in the physical network, in a virtual overlay on hypervisors, across the WAN via encrypted tunnel or one of many other options. Here, a mere connectivity is far less important than the orchestrated service establishment across many devices and platforms which SDN and NFV enable having a global view of the network in a virtualized DC.