The Total Learning Architecture (TLA) program sponsored by the Advanced Distributed Learning (ADL) Initiative seeks to develop a set of policy and standards defining the process for developing a "learning ecology," where multiple services and learning opportunities (of various modalities and points of delivery) can be managed in an integrated environment. The TLA employs a Service Oriented Architecture (SOA) approach to developing a flexible, modular system to optimize the time, cost, and effectiveness of learning delivery and analysis. It is composed of interchangeable software services and databases integrated to create an efficient learning environment for the user. The 2018 TLA research investigated relevant standards, specifications, and policies that relate to metadata strategies, competency representation, activity tracking, Learner Profiles, and numerous communications protocols, and interface specifications. Numerous specifications and standards were reviewed to investigate how they would influence the interoperable nature of the TLA. Candidate specifications were then implemented and tested within the 2018 TLA Reference Implementation. Within the TLA Reference Implementation, candidate standards and specifications are analyzed to determine whether the spec/standard is partially or entirely appropriate. If changes are required to extend the spec/standard, this work is documented to inform future standards/specification development bodies. The goal of the 2018 TLA Reference Implementation is to evaluate candidate standards and specifications for potential inclusion within the TLA. In creating the 2018 TLA Reference Implementation, the ADL Initiative started with a foundational understanding of existing Information Technology (IT) components commonly utilized in Distributed Learning (DL) today. Section 1 of this document discusses the future learning ecosystem, specifications and standards, the 2018 TLA Reference Implementation, the 2018 TLA test and demonstration, and the 2018 data analytics and visualization. Section 2 describes technical standards and specifications evaluated for use in the 2018 TLA Reference Implementation. Lastly, Section 3 provides a detailed description of the specific components and architecture used in the 2018 TLA Reference Implementation.