Network-as-a-service (NaaS) is gaining momentum, providing a subscription-based model that eliminates the need for enterprises to own, build, and maintain their own network infrastructure. By replacing conventional hardware-centric VPNs, firewall appliances, load balancers, and MPLS connections, NaaS technology promises adopters the ability to rapidly scale up and down in lockstep with demand while eliminating hardware costs and bolstering network security and service levels.\nWhy enterprises adopt NaaS\nEnterprises are generally attracted to the NaaS model by the potential to consume scalable network services at a predictable cost while shifting spending from capital expenses\u00a0to operating expenses, says Robert Smallwood, technology vice president at IT service management firm General Dynamics Information Technology (GDIT).\nNaaS's key benefits include rapid deployment, on-demand scaling, hands-off modernization refreshes, and access to the expertise needed to design and maintain today's increasingly complex mesh of interconnecting networks.\nNaaS adoption can also help IT leaders bring limited resources into alignment with strategic business goals. "There's considerable power in freeing-up an organization\u2019s internal IT resources to refocus and prioritize on measuring and meeting business objectives," says John Chambers, director of the network and unified communication solutions team at business consulting firm RSM US.\nNaaS's five-year outlook looks promising, Smallwood says. Gartner predicts NaaS will be adopted by 15% of all enterprises by the end of 2024, up from less than 1% in 2021, he says.\u00a0Mordor Intelligence, meanwhile,\u00a0forecasts a compound annual growth rate (CAGR) for NaaS of 33% between 2021 and 2026.\nSD-WAN, SASE, managed Wi-Fi and more\nThe NaaS umbrella covers a wide range of network services, including remote access, on-demand private L2 or L3 connectivity (including VPN), secure SD-WAN, SASE, security tools, cloud-based managed Wi-Fi, private LTE services, enterprise 5G services, and metro Ethernet services.\nSmallwood says he sees many enterprises taking a methodical approach to NaaS adoption, beginning with easier and more mature use cases, such as remote access and SD-WAN, and then moving to more holistic services.\nLeading NaaS vendors include cloud service providers such as Amazon, Microsoft, and Rackspace, as well as traditional communication service providers, including AT&T, Level 3 Communications, and Verizon. Other players include Akamai,\u00a0Alkira, Amdoc, Aryaka, Cisco, Megaport, PacketFabric, PaloAlto Networks, and Perimeter 81.\n"We see niche vendors continuing to emerge as service gaps are identified," Smallwood notes.\nNaaS will continue to grow and mature wherever required network functions can be virtualized and cloud deployed, says Mark Allen, director of network advisory services with technology research and advisory firm ISG. "The biggest growth opportunities will be driven by abstracting network functions away from costly on-premises equipment requirements to easily consumable services with commercial constructs that flex with demand for a given enterprise," he says.\nWhile many vendors claim to provide NaaS service, some offerings are actually little more than an underlying financing construct as opposed to a true service, Allen says. "Today, there are many pureplay 'XaaS' solutions for various functions previously reliant on physical hardware on the customer premises," he notes. Security, remote access, and VPN are increasingly being pitched as NaaS services.\nPandemic spurs NaaS adoption\nNaaS early adopters tend to be small-to-mid-sized enterprises carrying relatively low levels of technical debt, as well as agile organizations that are willing to assume a certain degree of risk, Allen says.\nNaaS is also attracting enterprises struggling with large-scale data flows, such as advertising and e-commerce organizations, plus customers with intense security requirements, including healthcare and financial services enterprises, says Alexander Wurm, an analyst with technology research and advisory firm Nucleus Research.\nOther early adopters include mature enterprises that fully understand the services they will need for long-term success. "These organizations have already adopted other services in an as-a-service model and understand what's required to successfully move to those delivery models," Smallwood says. Still other early adopters are enterprises juggling limited budgets that view NaaS as a pathway to reducing some of their capital expenses.\nThe pandemic has also played a significant role in spurring NaaS adoption, Chambers says. "During the early days of COVID-19 there was a rapid push for users to be able to connect quickly, reliably, and securely from anywhere at any time," he says. "This required many companies to make hardware\/software purchases and rapid implementations that accelerated an already noticeable increase in overall network complexity over the last several years."\nUnfortunately, many organizations faced serious challenges while trying to keep pace with suddenly essential changes. "Companies that need to quickly scale up or down their network infrastructure capabilities, or those that are on the cusp of major IT infrastructure lifecycle activity, have become prime NaaS-adoption candidates," Chambers says.\nIt\u2019s easiest for organizations to adopt small-scale NaaS offerings to gain an understanding of how to evaluate potential risk and rewards and determine overall alignment to their organization\u2019s requirements. "NaaS providers need to offer different levels of service that allow the enterprise\/organization to pick the degree of NaaS," Smallwood says. "This could include a hardware-only subscription, a managed service, or a full-blown true NaaS where the provider owns, installs, and operates all the equipment."\nEnterprises, meanwhile, will need to look past their initial fear of change and perceived loss of control to "recognize the real benefits that NaaS could provide them, especially in this remote work, security-focused, and more cloud-reliant world," Chambers says.\nAs more services are virtualized and packaged for easy use, the NaaS market will continue to grow rapidly, Allen says. "NaaS will benefit from enterprises continuing to adopt hybrid workforce models, particularly in the post-pandemic era," he adds.\nNaaS migration issues\nIf approached intelligently, a NaaS migration shouldn't be particularly difficult or time-consuming, according to Allen. "The tricky part is the lead-up\u2014getting the house in order before significant technology change can be successful," he says. "This involves auditing the network and adequately segmenting functions for transformation to NaaS while determining what to do with those that are not."\nBrownfield deployments tend to be more challenging than greenfield installations, Smallwood observes. "For example, in brownfield deployments, there may be compatibility issues where the NaaS vendor's infrastructure isn\u2019t compatible with legacy systems," he says. "Migrating applications and processes may be challenging if those applications and processes are running in on-premises data centers and not in the cloud."\nAnother potential stumbling block is that the NaaS provider may have only a limited number of the APIs needed to successfully move legacy network services to the NaaS model. "Having multiple vendors providing different parts of the network services can also complicate moving to NaaS," Smallwood says.\nIn addition, NaaS customers and providers frequently hold divergent viewpoints.\n"We often see a chasm between vendor and customer understanding of what's possible and applicable," Allen says. In a complex and evolving marketplace, vendors are stacked at different maturity levels, which colors their definitions and service offerings. He suggests running a Request for Solution (RFS) process to determine an appropriate set of vendors. "During the RFS, areas of particular concern should include term commitments, cost, billing structure, and technology utilized," Allen says.\nSmallwood recommends testing the NaaS waters with small, clearly identified projects, and moving onto more complex undertakings as experience is gained over time. "We're seeing an increased interest in as-a-service models such as NaaS, but also a bit of confusion as to how to move organizations from legacy IT models to as-a-service models," he notes.\u00a0\nPerhaps the most challenging NaaS candidates are enterprises running critical applications and systems within their on-premises data centers, not inside a public or private cloud. Such organizations may find shifting to NaaS more difficult than those that are already fully enmeshed in the cloud.\nFor organizations tied to physical data centers, Chambers advises taking a "crawl, walk, run" approach. "For example, a company considering an SD-WAN implementation could choose a NaaS approach for budgeting, implementation, and ongoing management of the SD-WAN platform, as opposed to a legacy CapEx model of adoption and its inherent limitations and risk\u2014namely less scalability and flexibility."\nSmallwood believes there will be no turning back from NaaS as adoption continues to grow rapidly over the next several years, but it may require a change in attitudes. "Successful adoption of as-a-service models, such as NaaS, are challenged by people with legacy mindsets who are fearful of a lack of control and can\u2019t definitively identify the measurable outcomes they require from the services," he says.\n\nLearn more about NaaS:\n\nNaaS is the future, but it's got challenges\nHow to avoid the network-as-a-service shell game\nCisco takes its first steps toward network-as-a-service\nCisco NaaS study: IT pros are interested but wary\nWhat is network as a service (NaaS)?