In this work, we propose and investigate a class-of-service-based multilayer architecture for traffic restoration in elastic optical networks. This architecture benefits from both data rate elasticity and low quality of service requirements of best-effort traffic in IP-over-WDM optical networks, combining 1 + 1 IP protection for gold traffic and optical restoration for best-effort traffic. Numerical simulations reveal that the proposed architecture can further reduce capital expenditures, even with the significant extra cost of elastic transponders