Network Functions Virtualization (NFV) is changing everything. NFV makes the network more flexible, more agile, more programmable. However, only if the end-to-end service is properly orchestrated across the heterogeneous network, can a service provider offer the high service variety and quality that customers want, quickly and cost-effectively via NFV.

NFV Challenges

The challenge is that NFV makes networks and their functions less deterministic. Traditional network functions are physical and relatively static in their configuration – measurable and consistent. Load balancers, firewalls, content filters, caching appliances: network operators have an excellent understanding of exactly what those devices do, what type of load they can manage, and how they perform under various load levels. Physical devices are typically over-engineered to withstand load fluctuations.

By contrast, the performance and capacity of an NFV-defined function are impacted by the multi-tenant hosting infrastructure (think network server) and the current load from all its applications. The workload on that infrastructure is constantly changing due to the context of the network at any point in time. Yes, NFV can enable flexibility and agility, but it’s hard to monitor exactly what’s going on – and therefore, proactively manage it.

That lack of determinism frustrates traditional means of administering the network, because the need for real-time Operations Support Systems (OSS) is moving deeper into the network itself. In an NFV world, network operators have to dynamically manage the life of each virtualized network function (VNF), in addition to managing end-to-end services. With those VNFs running on distributed hardware with disparate loads, there are three separate challenges:

• Managing each VNF

• Managing the segment of the customer’s service running on that VNF, or VNF
service chain, referred to as a ‘network service’

• Managing the customer’s end-to-end service across the entire network

Note that there are different definitions of ‘service’ floating around in the industry. For clarity, let’s refer to a service as complete end-to-end data connectivity for the consumer or enterprise spanning both physical elements and VNFs.

What’s that like in the real world? According to Scott Rayno of the Rayno Report, which recently surveyed enterprises on the subject of operations: “The top needs expressed through our research data are automation. People want to automate their networks. They want to enable web-based provision, especially for customers. They want agility. They want to rollout services on a faster delivery schedule. They want centralized management of multi-vendor platforms. They want governance of off-network elements, real time scaling, and a real time view into performance and fulfillment.”

The best way to manage these complex NFV-driven networks, and meet those customer demands, is with an orchestrator of orchestrators – a multi-tiered system focused on provisioning and assuring each of those functions.

Orchestrator of Orchestrators

At the lower level, a Domain Orchestrator (DO) manages the operational requirements of the individual VNF. Specifically, the DO manages the compute, storage, and networking requirements of the VNF. At the higher level, there’s the Lifecycle Service Orchestrator (LSO), which is in charge of specifying, provisioning, managing, and tearing down the customer’s end-to-end services across heterogeneous networks.

According to Rayno, “We define Lifecycle Service Orchestration as a software market. It’s software that integrates orchestration, fulfillment, control, performance, assurance, usage, analytics, security and calls to your networking services based on open and interoperable standards.” Clearly LSO encompasses a lot of functionality, and is a huge market; Rayno says the market will approach US$3 billion by 2019.

This functionality could include what is currently being defined within the ETSI NFV MANO reference architecture as a Service Orchestrator (SO). The SO manages customer- oriented services across various virtualization domains, by marshaling individual VNFs together into a ‘network service.’ Think of the SO as the means of instructing multiple DO instances how to configure and connect their VNFs across the network.

The LSO not only manages VNFs by controlling, or even including the functionality of, SOs, but also seamlessly orchestrates services across both VNFs and traditional Physical Network Functions (PNFs) that aren’t implemented via NFV. The functions of LSO are being defined by the MEF, which is collaborating closely with ETSI.

That brings up a challenge: SDN, NFV and LSO present an incredibly dynamic environment with multiple vendors building solutions in parallel with standardization efforts. There is a lot of difference between what is specified in the standards, what’s being discussed at standards bodies — and what’s really happening in the real world.

Benefits of LSO

The above might imply that network operators need three separate pieces of orchestration software, requiring complex integration, in order to set up VNFs (DO), set up customer services on those VNFs (SO), and finally combine them into end-to-end services (LSO).

Fortunately, that’s not the case. Modern-day comprehensive software solutions can implement required orchestration functions using open, flexible APIs, enabling management from a single pane of glass. LSO software can eliminate complexity within heterogeneous networks comprised of both traditional PNFs and next-generation VNFs turning what could be disjointed, time-consuming operations into a streamlined and user- intuitive management implementation.

A big benefit of LSO is hiding complexity while enabling agility and flexibility. The operator does not need to understand all the details of every implementation of each VNF on the underlying network. The infrastructure complexity is abstracted and hidden from the service-oriented view. And that’s how it should be, otherwise every part of the system would be buried in too many details, and managing end-to-end services would become far too complex — without any benefit to the carriers or to the end customers.

The upside is that service providers can offer customers flexible, programmable, agile, and scalable solutions, leveraging the capabilities of NFV while taking into account the non-deterministic nature of VNFs within a real-world network. Operators can realize the CAPEX savings NFV promises, without being bogged down by OPEX increases. By adopting an ‘Orchestrators of Orchestrators’ operational model, it’s a win-win for operators and customers.


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