Resource-efficient protection scheme for optical service units in fifth-generation fixed networks

One of the visions of fifth-generation fixed networks (F5G) is to provide a guaranteed reliable experience (GRE). Optical transport networks (OTNs) represent a primary candidate technology to offer high-quality bandwidth in F5G and hence to support GRE. Unfortunately, current OTN technologies provide large-bandwidth tunnels for carrying aggregated (typically, Ethernet) traffic, and corresponding protection techniques in OTNs consume a lot of resources. The emergence of a new technology called an optical service unit (OSU), which subdivides the payload block of traditional optical data units into smaller units, allows for the development of more flexible and resource-efficient protection schemes. In this paper, we propose a new resource-efficient protection scheme for OSU-based OTNs called OSU protection (OSU-P), with the aim to save network resources while providing individual customized protection for each single user. OSU-P only reserves small-bandwidth protection/backup connections for protected services; then, when a failure occurs, the protection bandwidth is adjusted to the bandwidth required by the service during the switching process. This scheme can save a significant amount of network resources, but it may encounter resource conflicts between the protected services and other preemptable services after a failure occurs. Hence, we also propose a deterministic protection algorithm and a preemptable service provisioning algorithm based on overlapping risk avoidance, which can ensure successful recovery switching of protected services and the least impact on preemptable unprotected services after a network failure occurs. Simulation results show that, compared with traditional
${1} + {1}$
and 1:1 protection schemes, OSU-P can reduce spare resources allocated for protection by about 30% and 11%, respectively, and reduce the blocking rate by about 27% and 10%, respectively. The performance of the proposed algorithms in terms of the percentage of unsuccessful protection and affected preemptable services is also verified.