Network Slicing with Elastic SFC

Network slicing often involves instantiation of certain network functionality into network nodes, possibly subject to function chaining constraints. In this paper, we introduce the novel concept of elastic service function chain (SFC), which is an ordered list of virtual functions that may be optional or recursive, and we address network slicing with such chaining constraints as a Software Defined Topology (SDT) problem. We formulate the SDT problem as a combinatorial optimization problem that includes a multi-commodity flow problem and a bin packing problem as sub-problems. Since it inherits NP hardness from the bin packing sub problem, we develop a heuristic algorithm to tackle it. The algorithm's effectiveness and performance are evaluated via simulation study.