NaaS (Network as a Service) Platform Architecture

Network-as-a-Service (NaaS) is a new digital business technology approach that is redefining how organizations create, consume and adapt connectivity and network capabilities. By streamlining internal operations, it enables service providers to transform the experience they offer to their enterprise customers. NaaS can be used by service providers both internally to expose network services for the IT department to consume whilst streamlining internal operational processes (as for example at Telstra); and externally to offer enterprise customers the ability to buy network resources and connectivity as a service which they can manage and adapt to their own specific needs (as for example at Globe).

• cloud service category in which the capability provided to the cloud service customer is transport connectivity and related network capabilities
• NaaS services are divided into network application service, network platform service, and network connectivity service. In particular, NaaS connectivity service is an “infrastructure capabilities type” service (limited to networking resources).

The goal of the NaaS model is to enable tenants to use the network infrastructure in a data centre (DC) more efficiently, addressing the shortcomings discussed in the previous section. In this section, we first motivate the functionality that the NaaS platform should offer, then outline the requirements that the implementation should fulfil, and finally discuss our proposed architecture and programming model.

NaaS means optimizing resource allocation by considering network and computing resources as a unified whole. NaaS, with a complementary marketplace, enables value-added services and infrastructure to be ordered and managed via an enterprise self-service portal. This provides a single unified view, in near real-time, of on-demand connectivity to clouds, data centers, applications and services as well as of virtual network functions (VNFs) from the full range of vendors in the third-party ecosystem. NaaS is now changing the traditional network experience offered to enterprises into a transformed business and customer experience that delivers the choice, agility and control to match rising enterprise customer business needs, enabling them to engage and interact with employees, partners and their own end customers in new, diverse ways.

What’s in it for the service provider and the enterprise customer?

With NaaS, service providers can offer their enterprise customers not only network capacity or access speed, but also a network that they can manage and adapt to their specific needs. By exposing their network to be consumed as a service, service providers are empowered to elevate themselves in their enterprise customers’ value chain, thereby increasing “stickiness” through service bundling.

Key benefits for service providers include:

• Increased enterprise revenue opportunities
• Shorter time to market for network and business service bundles
• Elimination of manual fulfillment and approval activities via automation From the enterprise customer’s perspective, NaaS offers a consumer-like experience with choice, scalability, visibility and control. Furthermore, it makes networking easy with simpler and faster on-demand provisioning of network services that can be customized to better serve the enterprise’s own end-customers. This means, for example, that the enterprise IT manager can instantly and independently order, provision, monitor and manage new and existing services for branch offices within the virtual private network (VPN) without the need to call or wait for a technician’s visit (Telus’ approach is a good example of this). Network-as-a-Service (NaaS): going beyond connectivity for enterprise revenue growth Highlighting the top three requirements for a successful NaaS deployment

A NaaS offering typically consists of three main components, which are critical to ensuring a successful deployment:

1. Connectivity – This component centers around providing network links with predefined QoS and bandwidth. Since NaaS is agnostic to underlying backhaul technology it can be based on wireline (fiber/ copper), wireless (microwave), IP/MPLS, SD-WAN or even mobile 5G. According to IDC, the software defined wide area network (SD-WAN) infrastructure market is poised to reach $4.5 billion in 2022.
2. Self-service portal :- the enterprise self service portal is a key capability that enables enterprises to connect or update a branch office or access the ecosystem of virtual network functions (VNFs) in near real-time. Once connectivity has been established, the enterprise IT or network operations manager can manage their own network services and value-added-services (VAS) via the NaaS portal and integrated VNF marketplace – all at the click of a button. The NaaS solution provides full automation, including settings and policies for each application, allowing the user to modify, adapt and scale their network as needed. Additional options, like redirecting traffic to the most efficient route with SD-WAN technology or configuring a local internet breakout for a specific branch office, can all be done using the self-service portal. The result is that the need to call the service provider or wait for a technician to arrive is removed.
3. VAS and VNF Marketplace : – This component enables the purchase of value added services and VNFs as well as dynamic allocation of storage, computing and networking resources by the NFV orchestrator (NFVO). The marketplace solution supports ongoing service delivery through integration with other applications such as CRM, CPQ, billing, network inventory and the service catalog. For a good example, see Telstra’s VNF marketplace.

Functionality

For simplicity, we present the three functions of NaaS separately, although in practice they are used together.

Network visibility : Many of the applications presented in Section2are built on top of overlay networks. To achieve high performance, great effort must be made to optimise the mapping between the logical and physical topologies. Since existing DCs are characterised by high degrees of over subscription [10], taking into account rack locality in the overlay layout can have a significant impact on performance. Several solutions for inferring network locality have been proposed. For example, Orchestra uses a sophisticated clustering protocol to discover the DC topology and leverages this information to efficiently laydown its tree-based overlay. While black-box approaches are necessary in an open environment such as the Internet, the DC provider has an accurate knowledge of the topology and could make this information available to tenants at no extra cost. This would allow tenants to efficiently allocate overlay nodes to VMs, without requiring expensive and often in accurate probing solutions.

Custom forwarding : Network visibility would yield a significant performance improvement for overlay based applications. However, there are some fundamental limits to the performance achievable using overlay networks. Since servers have usually only one NIC, even a simple multicast tree with a fan out greater than one cannot be optimally mapped to the physical network. Therefore, the second functionality that NaaS should provide is the ability to control packet forwarding at switches. This would allow the implementation of custom routing protocols. Examples include content-based and content-centric networking, but also tenant-specific firewalls, packet scheduling and load-aware any cast.

In-network processing : The main benefits of NaaS come from providing in-network packet processing capabilities as part of the cloud computing platform. For in-stance, distributed computing platforms, such as Map Reduce and Dryad, as well as real-time streaming systems and search engines operate on large amounts of data that are often aggregated between stages. By performing in-network aggregation, it is possible to significant reduce the overall traffic sent over the network, thereby greatly reducing execution times. Note that these aggregation functions are application-specific and, hence, could not be provided as a traditional network service. Another application that would benefit from this functionality is a distributed caching service, similar to mem-cached. For example, by leveraging the ability to intercept packets on-path, it would be possible to implement opportunistic caching strategies based on how many times.

Requirements

For a NaaS model to be used in DCs, we believe that the following requirements must be satisfied:

Integration with current DC hardware :  Existing DCs constitute a significant investment. The use of commodity networking equipment, which typically lacks programmability features, reduces the cost of large DC deployments. For NaaS to become successful, it must not require expensive, non-commodity, networking hardware.

High-level programming model : NaaS should ex-pose a programming model that is natural for software developers to use, hiding low-level details of network packet processing and not exposing the full complexity of the physical network topology in the DC.

Scalability and multi-tenant isolation : Compared to existing software-based router solutions, NaaS must be able to support a multitude of different applications, written by different organisations and running concurrently, unaware of each other. Therefore, to be successful, a NaaS model requires strong isolation of the different network resources offered to tenants

In the digital era, NaaS is empowering service providers to enhance and quickly adapt the user experience they offer their business customers, user experience that is more consumer like in its flexibility and immediacy. Deployed correctly and strategically, the three components mentioned above will result in network and value added services that are:

• Easy to manage and fully automated: Intuitive, experience-driven user interface based on design-ledthinking, with full automation of the entire order-tocare process across hybrid network and cloud domains
• Configurable in real-time: Providing live services ondemand and as-a-service, and which can be tailored and configured according to differing business needs. This eliminates the need to acquire, install and maintain specialized hardware at the enterprise’s premises. Furthermore, it enables modular and virtualized networks to act as business accelerators that allow services to be rolled out in a phased manner and support freemium-to-pay models, consumption-based pricing, service experimentation and other innovative approaches.
• Dynamic and scalable: Supporting elastic and flexible resource allocation capable of self-healing, as well as performance optimization based on analytics and machine learning. Raising, provisioning and monitoring orders is agile and configurable, and can be controlled by the enterprise itself.

Architectural framework

The architectural framework behind a successful NaaS deployment is still being developed by the industry. One of the early proposed NaaS frameworks was published as open source by T-NOVA and part of it is still available on Github. T-NOVA’s aim was to design a management/ orchestration platform for the automated provision, configuration, monitoring and optimization of network functions-as-a-service (NFaaS) over virtualized network and IT infrastructures. From T-NOVA’s reference architecture, it is clear that successful NaaS deployment requires tight integration and seamless workflow automation between the different modules. Starting from the top of the diagram, the architecture includes the marketplace with its sub-modules (e.g. SLA management, billing, brokerage), the NFV orchestration and NFV infrastructure layers, all the way down to configuring the actual physical and virtual elements in the network. An efficient NaaS platform leverages and enhances cloud management architectures for the elastic allocation and provision of IT resources. It should also be able to extend SDN platforms for efficient management of the network infrastructure.

Operational challenges

Gartner’s Strategic Roadmap for CSP NaaS and VNF Marketplace Platform Operations1 report, outlines the gaps between the current state of service providers’ digital platform business operations, and the desired state. These gaps include:

• Few NaaS solutions with limited self-service and marketplace capabilities
•  Low level of automation for the entire service lifecycle resulting in complex and manual VNF testing and onboarding
• Closed systems with limited proprietary VNFs
• Fragmented service factory challenged by simultaneous orchestration of hybrid physical and virtual network and IT resources
• Inefficient VNF license management to support a dynamic and real-time marketplace, while missing a consistent VNF licensing model
• Lack of standardization due to significant variations in vendors' VNF management (VNFM) and issues with compatibility with existing network management platforms. This is preventing the realization of efficient VNF lifecycle management and a marketplace from becoming scalable

The above challenges and gaps create the need for an integrated NaaS solution that addresses the offering, deployment and management of VNFs over hybrid physical and virtual infrastructures. Such a NaaS solution should implement an integrated management architecture that incorporates NFV orchestration, while leveraging cloud computing and SD-WAN management of network resources. Furthermore, it should include an open VNF marketplace with a set of associated, pre-onboarded third-party VNFs, sourced from an open, multi-vendor ecosystem. 

Amdocs

’NaaS approach Amdocs’ modular and programmable NaaS solution enables service providers to rapidly design, deploy and monetize on-demand NaaS offerings for their enterprise customers, combining virtualized network infrastructure and services with cloud and business applications. It automates, orchestrates and simplifies the design, ordering and management of both network services and value-added services for faster time to market, increased efficiency and a transformed customer experience.

Key features of Amdocs NaaS solution include:

• End-to-end programmable and modular service lifecycle automation and orchestration
• Core functions package (SD-WAN, security and more) for rapid, low-cost deployment of cloud-based network and value-added services
• Experience-driven, design-led enterprise self-service portal with network configuration capabilities supporting automated service lifecycle workflows
• Value-added-services and VNF marketplace capable of monitoring and charging usage
• Open ecosystem of pre-integrated third-party VNFs
• Innovative VNF license usage management using blockchain to simplify the management of multiple VNF licenses from many vendors Anatomy of NaaS Service Lifecycle Management Operational & Assurance Service Design & Create Live Network Service SD-WAN Self-service portal VNF Marketplace Orchestration Big Data Analytics Active Inventory Catalog Model Network Service management Continuous real-time fulfillment Offline design On-board VNFs Test and debug Instantiate service Monitor & assure Service request (new/update) Design service Package and distribute Telco cloud Public clouds BSS Monetization VNF License Usage Management (Ordering & Billing) $ Static model Dynamic info
• Automated service factory that handles the entire service lifecycle from service design and VNF onboarding through service fulfillment, VNF instantiation and orchestration, all the way to ongoing closed-loop assurance and maintenance.
• Integration with master catalog, customer management and billing systems for end-to-end automation of the order-to-care process