Coordination Algorithm for Migration of Shared VNFs in Federated Environments

Several works in the literature have proposed migration mechanisms for VNFs, however they only consider the migration of isolated Virtual Network Functions (VNFs) instead of the migration under a shared and chained scenario. Reconfiguration of VNFs, like in the case of migration, is necessary to handle dynamic requirements for the service. However, it is not a straightforward operation. On one hand, it is necessary to coordinate VNFs to achieve migration while maintaining the end-to-end service availability. On the other hand, the new deployment can disrupt the chain and violate predefined services constraints. Moreover if there is no access to global references, migration can introduce inconsistent services due to a lack of knowledge from orchestrators. This paper focuses on the problem of coordinating orchestrators in a NFV federation to achieve migration of shared VNFs with only local domain information. It introduces a novel coordination algorithm that relies on ETSI/MANO specifications. The proposed algorithm is implemented and evaluated for validation purposes. Results show that migration satisfies the constraints for seamless migration and the algorithm obtains better performance compared to state of the art solution with a slight overhead cost when considering the shared VNFs instead of isolated VNFS.