Effectiveness of segment routing technology in reducing the bandwidth and cloud resources provisioning times in network function virtualization architectures

Network Function Virtualization is a new technology allowing for a elastic cloud and bandwidth resource allocation. The technology requires an orchestrator whose role is the service and resource orchestration. It receives service requests, each one characterized by a Service Function Chain, which is a set of service functions to be executed according to a given order. It implements an algorithm for deciding where both to allocate the cloud and bandwidth resources and to route the SFCs. In a traditional orchestration algorithm, the orchestrator has a detailed knowledge of the cloud and network infrastructures and that can lead to high computational complexity of the SFC Routing and Cloud and Bandwidth resource Allocation (SRCBA) algorithm. In this paper, we propose and evaluate the effectiveness of a scalable orchestration architecture inherited by the one proposed within the European Telecommunications Standards Institute (ETSI) and based on the functional separation of an NFV orchestrator in Resource Orchestrator (RO) and Network Service Orchestrator (NSO). Each cloud domain is equipped with an RO whose task is to provide a simple and abstract representation of the cloud infrastructure. These representations are notified of the NSO that can apply a simplified and less complex SRCBA algorithm. In addition, we show how the segment routing technology can help to simplify the SFC routing by means of an effective addressing of the service functions. The scalable orchestration solution has been investigated and compared to the one of a traditional orchestrator in some network scenarios and varying the number of cloud domains. We have verified that the execution time of the SRCBA algorithm can be drastically reduced without degrading the performance in terms of cloud and bandwidth resource costs

Proposal and investigation of a scalable NFV orchestrator based on segment routing data/control plane

Network Function Virtualization (NFV) has attracted significant interest in recent years due to its agility to adopt new technology and its flexibility in on-demand deployment of network functions. A major topic in the field of NFV research is the allocation and orchestration of VNF instances to provide satisfying network services according to user demands. The paper proposes and investigates a new solution for a scalable NFV Orchestrator allowing for a reduction of the needed time for the Service Function Chain routing and the allocation of cloud and bandwidth resources. That is obtained by abstracting and simplifying in the NFV orchestrator the knowledge of both the network topology and the resource amount available in the datacenters in which the Virtual Network Functions are executed. The solution is based on the Segment Routing paradigm that allows to implement the scalable orchestration at data plane level. Finally we show how the proposed solution reduce by 90% the time needed to execute an SFC routing and resource allocation algorithm with respect to a traditional orchestration solution