The ACINO (Application Centric IP/optical Network Orchestration) project’s aim was to develop and demonstrate a dynamic, application-centric, multi-layer SDN network orchestrator, where the traffic of each application receives a tailored service at each layer of the transport network, thereby overcoming the gap that the grooming layer introduces between application service requirements and their fulfilment in the lower layers of the stack.
ACINO implemented the proposed concept by following three main technological pillars: learn, think, act. More specifically, the project was one of the pioneering European research activities that focused on intent-based networking to learn about the applications’ needs. Towards this objective, ACINO defined the information model representing the primitives that can be provided to applications to expose network functionalities and developed a grammar to explicitly describe requirements for network services without delving into the details of the underlying technologies, by means of a newly-developed controller-agnostic intent-based interface called DISMI.
Given an intent request with its set of requirements, an application-centric optimization solution elaborates (think) the most proper allocation of resources that satisfies them. The tool that transforms high-level requests into installable paths was developed on top of Net2Plan, an open-source optimization tool. ACINO defined an algorithmic framework that relies on multi-layer provisioning of individual connections. Application-centric (or application-aware) decision policies operating with many parameters (e.g. latency, availability, security, etc.) were included into this framework and compared with non-application-centric policies. Furthermore, online (in-operation) planning was included, with the aim of providing multi-layer, on demand, real time network resource re-optimization and/or re-configuration based on applications’ needs.
All the decisions made by the application-centric optimization are appropriately translated into a network state by the multi-layer network control suite (act), which is the core part of the orchestrator. The orchestrator triggers and/or executes the provisioning of resources and the configuration of devices operating at the IP and optical data plane. ACINO selected ONOS as the open-source framework for the core modules of the orchestrator and modified it to connect to the DISMI interface and process the intents, to expose a disaggregated multi-layer network model, to cooperate with Net2Plan, and to generally support the operations defined in the project. New southbound drivers, based on existing and emerging standards (e.g. the ONF Transport-API) were implemented in ONOS to manage the IP and optical layers.
The ACINO concept has been evaluated by means of techno-economic analysis. Starting from the purely technical matters, it has been demonstrated that the ACINO application-aware solution outperforms application-unaware ones in terms of amount of services that can be accommodated in the network while satisfying application requirements. More specifically, it has been observed that, while ACINO accepts slightly less requests than application-unaware solutions, it does not violate any requirements for the ones accepted, and the sum of these two metrics (acceptance ratio and violation of requirements) qualifies ACINO as a superior solution. On the other hand, application-awareness generally comes at a cost in terms of number of required interfaces (or IP links). The impact on capital expenditure is however mitigated by the opportunistic optimization of resources at both IP and optical layers that is carried out by ACINO. This aspect was indeed subject of a cost study, which highlighted that in order to achieve the same performance of ACINO, operators that have their optical layer optimized with typical offline planning and optimization algorithms would need to overprovision their network and afford higher costs compared to the ones required to adopt the ACINO approach: in some scenarios, more than doubled costs were observed.
Three testbeds, two physical and an emulated one, were setup to experimentally validate the ACINO approach and the defined use cases (5 use cases were demonstrated, and another 3 demonstrations were produced). Each use case highlighted the qualitative benefits of ACINO, mostly in terms of multi-layer application-centric functionalities that are offered to network operators and their customers. For instance, ACINO demonstrated the capability to provide on-the-fly security services at different network layers (i.e., IPSec, MACSec or Optical Sec) over mission-critical infrastructures for sensitive applications, according to their requirements (e.g. latency, throughput and payload overhead), while taking into account network flexibility and availability of hardware. In another use case, ACINO demonstrated the capability of its orchestrator to opportunistically provide the most suitable reactive (slow) or proactive (fast) survivability solution for connectivity services with different requirements in terms of availability (e.g. drone control versus video transfer, potentially belonging to the same customer).
The ACINO consortium described how current Operations Support Systems (OSS), deployed by network operators, could evolve to embrace SDN orchestration as proposed by ACINO, in order to reduce human intervention and time required to establish services, thereby decreasing the operational expenditure. From a future perspective, the consortium delineated the capability of the ACINO solution to unlock new business models (not available with currently envisioned multi-layer SDN orchestrators) in which network operators can allow applications from external players to interact with the orchestrator to provide multi-party service offerings, directly program the network behaviour and negotiate service requirements.
The outcomes of the project were largely disseminated and communicated by means of different channels (including the project website and Twitter account), with more than eighty different dissemination activities (articles, presentations, tutorials, etc.). Moreover, the members of the consortium have been very active in the standardization bodies (IETF and ONF) and in contributing to open source communities (ONOS and to a lesser degree Net2Plan). ACINO partners have been able to exploit the project outcomes by introducing novel intent-based application-aware solutions and open standard interfaces in their products, and by demonstrating them in commercial meetings and interoperability tests with major vendors and operators.