A Smart Contract based Spectrum Trading System for Elastic Virtual Optical Networks

An Elastic Optical Network (EON) nowadays usually accommodates multiple Virtual Optical Networks (VON) by allocating orthogonal spectrum resources for them. A fixed resource allocation pattern may result in a low quality of service since data traffic on VONs may fluctuate with time. Spectrum trading (ST) among VONs could solve this problem by moving spectrum resources between them and blockchain-based ST has recently gained much interest since it avoids the traditional centralization concern. In this paper, we propose a smart contract based decentralized ST scheme for VONs. The system is built on a private blockchain which can be implemented with the off-shelf Ethereum platform at a low development cost. A frequency slot (FS) trading contract (FSTC) is designed to trade unoccupied spectrum resources among VONs. Compared with existing schemes, FSTC explicitly addresses the virtual link brokerage (VLB) problem by trading in the granularity of virtual links. Furthermore, FSTC ensures FS information authenticity and enables FS recyclability via mechanisms based on Ethereum smart contract features. We implement FSTC with Solidity and evaluate its costs which demonstrate the feasibility of the proposed solution.