  Network slicing allows different applications and network services to be
deployed on virtualized resources running on a common underlying physical
infrastructure. Developing a scalable system for the orchestration of
end-to-end (E2E) mobile network slices requires careful planning and very
reliable algorithms. In this paper, we propose a novel E2E Network Slicing
Orchestration System (NSOS) and a Dynamic Auto- Scaling Algorithm (DASA) for
it. Our NSOS relies strongly on the foundation of a hierarchical architecture
that incorporates dedicated entities per domain to manage every segment of the
mobile network from the access, to the transport and core network part for a
scalable orchestration of federated network slices. The DASA enables the NSOS
to autonomously adapt its resources to changes in the demand for slice
orchestration requests (SORs) while enforcing a given mean overall time taken
by the NSOS to process any SOR. The proposed DASA includes both proactive and
reactive resource provisioning techniques). The proposed resource dimensioning
heuristic algorithm of the DASA is based on a queuing model for the NSOS, which
consists of an open network of G/G/m queues. Finally, we validate the proper
operation and evaluate the performance of our DASA solution for the NSOS by
means of system-level simulations.
