FRESCO: Fast and Reliable Edge Offloading with Reputation-based Hybrid Smart Contracts

2024-10-09

arXiv.org

AI Summary

To address the frequent violation of QoS deadlines in task offloading within distributed edge environments, this paper proposes a blockchain-based reputation-aware Hybrid Smart Contract (HSC) architecture: trusted state and reputation are maintained on-chain, while high-speed offloading decisions are executed off-chain. It introduces, for the first time, Satisfiability Modulo Theories (SMT) formal modeling to rigorously verify both offloading feasibility and real-time compliance, thereby guaranteeing strict adherence to latency constraints. The approach innovatively integrates a distributed reputation system, blockchain consensus, and SMT solving to jointly enhance reliability and efficiency. Experimental results demonstrate substantial improvements: QoS violation rate drops to 0.4%, response time reduces to 12.7% of baseline methods, energy consumption decreases by 5.4%, and average decision latency is merely 5.05 ms.

Technology Category

• Constraint Satisfaction and Optimization: Distributed CSP/Optimization
• Search and Optimization: Distributed Search
• Machine Learning: Learning on the Edge & Model Compression

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Energy management for devices in mobile Web and WoT environments
• Security and Privacy: Blockchains and distributed ledgers
• Economics, Online Markets and Human Computation: LLM based quality controls for crowd work

Abstract

Mobile devices offload latency-sensitive application tasks to edge servers to satisfy applications' Quality of Service (QoS) deadlines. Consequently, ensuring reliable offloading without QoS violations is challenging in distributed and unreliable edge environments. However, current edge offloading solutions are either centralized or do not adequately address challenges in distributed environments. We propose FRESCO, a fast and reliable edge offloading framework that utilizes a blockchain-based reputation system, which enhances the reliability of offloading in the distributed edge. The distributed reputation system tracks the historical performance of edge servers, while blockchain through a consensus mechanism ensures that sensitive reputation information is secured against tampering. However, blockchain consensus typically has high latency, and therefore we employ a Hybrid Smart Contract (HSC) that automatically computes and stores reputation securely on-chain (i.e., on the blockchain) while allowing fast offloading decisions off-chain (i.e., outside of blockchain). The offloading decision engine uses a reputation score to derive fast offloading decisions, which are based on Satisfiability Modulo Theory (SMT). The SMT models edge resource constraints, and QoS deadlines, and can formally guarantee a feasible solution that is valuable for latency-sensitive applications that require high reliability. With a combination of on-chain HSC reputation state management and an off-chain SMT decision engine, FRESCO offloads tasks to reliable servers without being hindered by blockchain consensus. We evaluate FRESCO against real availability traces and simulated applications. FRESCO reduces response time by up to 7.86 times and saves energy by up to 5.4% compared to all baselines while minimizing QoS violations to 0.4% and achieving an average decision time of 5.05 milliseconds.

Problem

• Ensuring reliable task offloading without QoS violations
• Addressing high latency in blockchain consensus mechanisms
• Providing fast offloading decisions in distributed edge environments

Innovation

• Blockchain-based reputation system for reliability
• Hybrid Smart Contracts for fast offloading decisions
• SMT solver for QoS-aware resource allocation