Less is more: Why one VNF is better than four VNFs

Most service providers are continuing to invest significant capital and operational resources in selecting, on-boarding, testing and integrating various vendor-specific virtualised network functions (VNFs) as part of a long-term network functions virtualisation (NFV) strategy.

On-boarding VNFs is the process by which a VNF is made available on an NFV platform, permitting its life-cycle operations, such as deployment, scaling, healing, software upgrades and termination to be fully automated.

The transformation from traditional hardware-oriented managed services environment to software-defined and virtualised managed services is complex and challenging for managed service providers.

The transformation requires integration with new orchestration systems, familiarisation with DevOps tools for managing these virtual functions (VFs) and the integration of various VNFs on to x86 virtualised CPE (vCPE) platforms. All this requires further integration, performance testing and portal development for every new VNF added.

VNF functions are a more efficient way for a service provider to deliver multiple or tiered network services to enterprise branch sites via a single physical appliance, simplifying and consolidating branch site infrastructure sprawl. For distributed enterprises, VNF-based managed services expedites provisioning time from months to days or hours. Leveraging software VNF functions also enables enterprises to easily order or change network functions in alignment with changing business requirements.

For a typical service provider that is offering a range of virtualised managed network services such as managed CPE router, managed SD-WAN, managed WAN optimisation and a managed firewall, the path to migrating to a virtualised multi-VNF environment operating on a vCPE or a 'white box' is no small task. In fact, according to a recent SDXcentral survey, 80%  of service providers view managed SD-WAN services as the leading NFV use case in 2017.

To put the challenge into perspective, each of these four VNF functions could require a separate VNF to operate:

- CPE router: vRouter VNF

- SD-WAN: SD-WAN VNF

- WAN optimisation: WAN optimisation VNF

- Stateful firewall: vFirewall VNF

That's four unique VNFs on a vCPE platform, all of which must be qualified through the on-boarding process and integrated into the managed service provider's billing and management OSS/BSS framework. In some cases, service providers have selected different VNF vendors for each of these four categories. This can lead to additional layers of complexity and begs the question. How do these multi-vendor VNFs perform when they are operating simultaneously on a single vCPE and for different configurations?

What if you could combine all four VNF functions listed above into a single VNF that is one software image that runs in a single virtual machine (VM)? Service providers would immediately be able to support a set of tiered, managed services that include managed routing CPE, managed WAN optimisation, and integrate SD-WAN with managed firewall services.

That's exactly what advanced SD-WAN vendors deliver to service providers today. These four functions are available as VNF which simplifies the integration into the service provider's orchestration system(s). This VNF supports a vRouter with BGP routing, a fully featured SD-WAN solution with SaaS optimisation, WAN optimisation and a stateful firewall all available as a single VNF. The single VNF also consumes a single virtual machine (VM) for the four functions in contrast to other vendor solutions that require a dedicated VM for each of the four functions.

A single VNF eliminates the significant testing, hardware costs, and expansive footprint of the hardware required to support a more traditional, multi-function VNF. It also simplifies the orchestration effort to support tiered managed services, which speeds time to service revenue.

In this world of complexity, a single VNF that supports the equivalent of four VNFs of managed services brings new meaning to the phrase, less is more.

By Nav Chander, Silver Peak