Network-as-a-Service(NaaS) is a term used to describe the provision of computer networking technology to an organisation as an integrated service.
Historic definitions focused on fundamental concepts of NaaS, including describing services for network transport connectivity.
[1][2] NaaS also involves the optimization of resource allocations by considering network and computing resources as a unified whole.
[3] With the emergence of cloud computing, NaaS has become the transport not only between dynamic collaborators outside of the cloud (an update to the classic enterprise WAN architecture), but also between enterprise resources in private, often multi-tenant, data center (MTDC) facilities and in the public Cloud Service Providers (CSPs), including the interconnection between all of these in a growing "cloud first" enterprise architecture.
Before the new WAN connectivity patterns, enterprise WAN architectures, and consumption models resulting from the adoption of cloud computing and the network programmability focus introduced by SDN, NaaS was sometimes used to describe more traditional network resource-sharing concepts like the provision of a virtual network service by the owners of the network infrastructure to a third party.