Experimental Evaluation of an SDN Controller for Open Optical-circuit-switched Networks

TL;DR

This work tackles the problem of open, vendor-neutral control for optical-circuit-switched networks by designing and implementing an MV-OCS controller with a unified MV-OCS SBI (OCS.yang) and an atomic, parallel fiber-path configuration mechanism. The architecture delineates a three-layer SDN-style framework with a robust northbound API for management, a translator-enabled southbound interface for multi-vendor OCSes, and internal components (FPCE, OCS renderer, health checks, and event/alarm manager) to ensure fast and safe path provisioning. Experimental validation on real MV-OCS deployments and large-scale emulations demonstrates fiber-path setup within 1.0 second, reliable rollback under OCS failures, and effective automatic restoration upon signal degradation, with field demonstrations in metro-access converged networks. The results support broader adoption of open MV-OCS control and point toward standardization and vendor collaboration to realize interoperable, low-OPEX optical networks.

Abstract

Open optical networks have been considered to be important for cost-effectively building and operating the networks. Recently, the optical-circuit-switches (OCSes) have attracted industry and academia because of their cost efficiency and higher capacity than traditional electrical packet switches (EPSes) and reconfigurable optical add drop multiplexers (ROADMs). Though the open interfaces and control planes for traditional ROADMs and transponders have been defined by several standard-defining organizations (SDOs), those of OCSes have not. Considering that several OCSes have already been installed in production datacenter networks (DCNs) and several OCS products are on the market, bringing the openness and interoperability into the OCS-based networks has become important. Motivated by this fact, this paper investigates a software-defined networking (SDN) controller for open optical-circuit-switched networks. To this end, we identified the use cases of OCSes and derived the controller requirements for supporting them. We then proposed a multi-vendor (MV) OCS controller framework that satisfies the derived requirements; it was designed to quickly and consistently operate fiber paths upon receiving the operation requests. We validated our controller by implementing it and evaluating its performance on actual MV-OCS networks. It satisfied all the requirements, and fiber paths could be configured within 1.0 second by using our controller.

Figures (17)

• Figure 1: The OCS use cases.
• Figure 2: Inconsistent network state due to operation failure of OCS #3. In this case, normal OCSes #1 and #2 should be rolled back to the previous network state (consistent network state).
• Figure 3: MV-OCS controller architecture.
• Figure 4: The goal of defining unified SBI. MV-OCSes should be operated by a unified interface.
• Figure 5: The function blocks of SBI translator.