This paper reports results of a performance comparison for four optical ring network architectures envisaged for future metropolitan area networks (MANs), with particular emphasis on the design of and compatibility to possible 100-Gigabit-Metro-Ethernet (100 GbME) standards. Both analytical and numerical modelling techniques were applied to quantify and compare network performance for all architectures in terms of achievable throughput, delay and the number of required wavelengths. Non-uniform traffic required additional resources and dynamic adaptation of the slotted ring architecture. The study also considered aspects of the physical transmission and interfaces (PHY)for consideration in 100 GbME standards.