Communication service providers deliver value-added services to customers based on their available network transport services. Some services extend beyond the boundaries of a single CSP and require the collaboration of several CSPs to provide inter-CSP services. Transport services for next-generation value-added services are currently based on expensive connection oriented technologies such as synchronous digital hierarchy and optical transport networks. Dataoriented technologies have recently been considered for transport networks (e.g., Ethernet and MPLS variants) due to their efficiency, simplicity, and better suitability for data traffic, which dominates the transport networks. Currently, CSP transport networks are isolated and inter-CSP transport service provisioning involves human-tohuman negotiations and manual setup of network devices. Next-generation CSPs must provide QoS intra-service-to-customer, inter-CSP, and customer-to-customer transport services that are generic, automatically provisioned, and based on business logic that can be expressed easily and uniformly. A transport service layer architecture for automatic provisioning of inter-CSP transport services is suggested here, based on standard Ethernet technology. This transport service layer architecture is part of the Ethernet transport network architecture that takes into account business relations among carriers. It enables various class-of-service transport services based on multiconstraint matching and optimizations. The resulting transport service provisioning is automated and optimized, and significantly decreases the involved inter-CSP service setup operations.