Futurewei Telefonica Intel Corporation Delivery of network services over a Layer 3 tunnel assumes that the appropriate setup is provisioned over links that connect the customer termination points and provider network. The required setup to allow successful data exchange over these links is referred to as an attachment circuit (AC) while the underlying link for carrying network services is referred to as "bearer", in this case a Layer 3 UDP tunnel. This document specifies an extension for UDP tunnel as Layer 3 bearer to the YANG service data model for AC.