Reliable Slicing of 5G Transport Networks with Bandwidth Squeezing and Multi-Path Provisioning

5G network slicing allows partitioning of network resources to meet stringent end-to-end service requirements across multiple network segments, from access to transport. These requirements are shaping technical evolution in each of these segments. In particular, the transport segment is currently evolving in the direction of elastic optical networks (EONs), a new generation of optical networks supporting a flexible optical-spectrum grid and novel elastic transponder capabilities. In this paper, we focus on the reliability of 5G transport-network slices in EON. Specifically, we consider the problem of slicing 5G transport networks, i.e., establishing virtual networks on 5G transport, while providing dedicated protection. As dedicated protection requires a large amount of backup resources, our proposed solution incorporates two techniques to reduce backup resources: (i) bandwidth squeezing, i.e., providing a reduced protection bandwidth than the original request; and (ii) survivable multi-path provisioning. We leverage the capability of EONs to fine tune spectrum allocation and adapt modulation format and forward error correction for allocating spectrum resources. Our numerical evaluation over realistic network topologies quantifies the spectrum savings achieved by employing EON over traditional fixed-grid optical networks, and provides new insights on the impact of bandwidth squeezing and multi-path provisioning on spectrum utilization. One key takeaway from our evaluation is that multi-path provisioning can guarantee up to 40% of the bandwidth requested by a VN during failures by provisioning only 10% additional spectrum resources. This also caused VN blocking ratio for BSR up to 40% to remain very close to that of the no-backup case.