6 research outputs found
Effectiveness of segment routing technology in reducing the bandwidth and cloud resources provisioning times in network function virtualization architectures
Get PDFNetwork 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
Integrita: Protecting View-Consistency in Online Social Network with Federated Servers
Get PDFCurrent designs of Online Social Networks (OSN) deploy centralized architecture where a central OSN provider handles all the users’ read and write requests over the shared data (e.g., Facebook wall or a group page). The historical incidents demonstrate that such centralization is leveraged for censorship and violating view consistency; a corrupted provider deliberately displays different views of the shared data to the users. Integrita provides a data-sharing mechanism that protects view consistency by replacing the centralized architecture with the federated-server model consisting of N malicious providers, N − 1 of which can be colluding. The state of the shared data is modeled by an append-only data structure, stored at the servers side, which contains the history of all the operations performed by the users. The consistency of users’ views towards shared data depends on their accessibility to the intact log of operations. Integrita guarantees that the servers cannot manipulate the log without being detected by the users. Unlike the state-of-the-art, Integrita accomplishes this neither by using storage inefficient data replication nor by requiring users to exchange their views. Every user, without relying on the presence of other users, can verify whether his operation has been added to the log and is visible to the rest of the users. We introduce and achieve a new level of view consistency named q-detectable consistency, where any inconsistency between users’ views cannot remain undetected for more than q operations where q is a function of the number of the servers. This level of consistency is stronger than what centralized counterparts offer. Also, our proposal reduces the storage overhead imposed by replication-based solutions by the multiplicative factor of 1/N. Furthermore, the application of Integrita is not limited to OSNs, and can be integrated into any log-based systems e.g., versioning control system as well
