In this work we evaluate Metro Ethernet over WDM ring networks using classical spanning tree protocol and the emerging connection-oriented transport Ethernet forwarding mechanisms like provider backbone transport or VLAN-crossconnect. The two architecture alternatives are evaluated based on a network dimensioning study, using a heuristic and a mixed integer programming approach, respectively. In network studies with several ring sizes we compare both Ethernet flavors for opaque as well as meshed virtual topology network models.