Transport services are currently based on expensive connection oriented technologies, e.g., Synchronous Digital Hierarchy (SDH) and Optical Transport Network (OTN). Data-oriented technologies are recently considered for transport networks, e.g., Ethernet and MPLS variants, due to their efficiency, simplicity, and better fitness to data traffic, which dominates the transport networks. A service layer architecture for automatic provisioning of inter-domain (and inter-carrier) transport services, which is based on the standard Ethernet technology, is presented here. This service layer architecture is part of the Ethernet Transport Network Architecture (ETNA) framework, which is agnostic to the intra domains technology (e.g., MPLS, Ethernet, or SDH), and allows operators to implement their preferred intra-domain technologies (e.g., MPLS, IP, SDH). ETNA's service layer architecture takes into account business relations among carriers, and enables various classes-of-service transport services that are based on multi-constraint matching and optimizations. The resulted transport service provisioning of various Ethernet services is quick, optimized, and decreases the involved OPEX significantly.