Taking into Account the Management Constraints in Network Slice Design

Abstract

The preparation phase of a network slice (NwS) involves design decisions such as determining the network functions (NFs) and network slice subnets the NwS consists of, propagating the requirements the NwS has to satisfy to these constituents and determining their optimal placement for meeting the requirements. Since an end-to-end NwS spans the radio access, transport and core networks, usually three network slice subnets are considered for it and assigned to appropriate portions of the network. Once the subnets of a NwS have been determined, its resource-level representation is elaborated on. To do so in the context of network function virtualization (NFV), a NwS is mapped to network service(s) (NS). According to current practice, a NwS is mapped to a composite NS consisting of nested NSs, where each nested NS realizes a network slice subnet. This paper identifies and addresses some of the limitations of this approach. Namely, the mapping of the NwS to NSs and nested NSs needs to consider, in addition to the placement information of the NwS constituents, the organization and capabilities of the NFV management system(s) involved. Currently these are considered only at the time of the NwS deployment, which may render the NwS design undeployable if the NwS to NSs mapping cannot be aligned with the scopes and capabilities of the involved management entities. Therefore, the approach proposed in this paper determines, for a given NwS, its constituent subnets and the realizing NSs by taking into account the management constraints together with the placement information applicable to the NwS.